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Food Living Outside Play Technology Workshop
Build A Net Gunby crispyjones on August 7, 2008
Table of Contents
Build A Net Gun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Intro: Build A Net Gun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Step 1: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Step 2: Net Procurement And Math . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Optional Net Math Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Alternate Net Substitution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
File Downloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Step 3: Build The Pressure Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Step 4: Build The Trigger Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Step 5: Assemble And Test Valve and Pressure Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Step 6: Bend Launcher Arms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
File Downloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Step 7: Build Launcher Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Step 8: Assemble Tractors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Step 9: Assemble Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Step 10: Loading And Firing The Netgun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Step 11: Et cetera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Mechanical Trigger Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Tennis Ball Launcher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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Intro: Build A Net Gun
I will show you how to build a net gun out of materials available at any big box home improvement store. This net gun is capable of firing a 90 square foot net 15 to 25feet using 80-100 psi of compressed air. The net is reusable, assuming your prey doesn't destroy or run off with it. The launcher section is modular and can be removedin case you want to use a different design or add attachments. Thread on some 1" PVC pipe and you have a Christmas Cannon , or check step 11 for how to build atennis ball launching attachment.
The net gun is similar to many pneumatic launchers, but instead of launching a single projectile, it launches four tractors that pull the net through the air. The tractors arebased on the fact that the neck of a standard soda bottle fits very well over the outside of 1/2" PVC pipe. The cost to build this will range from approximately $40-$75.
Image Notes1. Yup, it's a net gun. You should have one too.
Step 1: Materials
B efore you begin be aware that this project uses PVC pipe in an application it is explicitly not intended for. PVC is meant for water, not pressurized air or other gases.The problem is not the pressure, this project uses pressures less than half the working pressure of any PVC component, but the failure mode when pressurized by gas. Ifthe PVC is compromised, by dropping, impact, or other means, it shatters into sharp pieces that are ejected by the pressurized gas. An excellent discussion anddemonstration here , make sure to watch the video through to the end.
Nearly all of these items can be picked up at your local home improvement retailer. It is probably worth buying a full 10' length of 1/2" pipe, for all the other sizes see ifyou can buy shorter lengths or scrap. Alternatively, get some friends together, share the costs of the full length pipes, and build a lot of net guns. The tire valves areavailable at auto parts stores. The net is addressed in detail in the next step.
SUPPLIESAll PVC fittings are slip fit unless otherwise notedAll PVC pipe and fittings must be SCH-40 (SCH edule 40) unless otherwise notedAll PVC pipe should have a PSI rating of 200 or greater, absolutely no cell core ABS DWV pipe
Pressure chamber partsFig 1
1 1" MPT (M ale P ipe T hread) to 1" slip street elbow1 1" elbow1 2" to 1" reducer bushing1 2" cap1 2" coupler1 foot of 1" pipeminimum 9" length of 2" pipe**1 valve stem, prefer a .453" as it corresponds to the readily available 7/16" drill bitoptional 1 pressure gauge
**There are two standard size automotive valve stems, one for a rim hole sized .453" the other .625". These two sizes correspond to fractional drill bit sizes of 29/64" and 5/8" respectively, the much more
common 7/16" bit can be substituted in place of the less common 29/64". Additionally, most common drill indexes stop at 7/16" or 1/2" and do not contain the larger 5/8" bit.
Trigger valve partsFig 2
1 Orbit Model 57461 1" sprinkler valve1 Blow gun similar to this1 1/4" NPT hex nipple, like this
Bending jig
3 2"(ish) wood screwsWood scrap for base, a 16" length of 2x4 should work fine
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Launcher sectionFig 3
4 13" lengths of 1/2" pipe1 1/2" cross2 1/2" tee4 1/2" street elbows4 1-1/2" pieces of 1/2" pipe (coupler joiners)1 1-1/2" pipe 9" long1 1-1/2" coupler**1 1-1/2" to 1/2" reducing bushings** 1 1" MPT to 1/2" slip1 nickel
** these transitions usually can't be made with one adapter, just make sure the starting and ending dimensions are correct.
Net
Memphis Net and Twine sku# 263 1lb minimum order is enough to make 7-8 netsOR a substitute net computed using the net math spreadsheet and instructions in step 2Nylon mason's twine (#15 or smaller), kite string, or some other thin durable rope4 per net 16-20oz carbonated soda bottles4 per net zip ties > 4" longHot glue/silicone/wax to pour in bottles to add weightOptional additional items needed for high performance net tractors4 per net 3/4" couplers4 per net 3/4" caps4 per net 8" lengths of SDR-21(Class 200) 3/4" thinwall PVC note: regular 3/4" SCH40 will NOT work!4 per net 12" lengths of non-adhesive 1" ID foam pipe insulation. Pipe insulation is generally sold in 6' lengths.
Consumables
PVC pipe cement and primerPVC safe pipe joint compound (pipe dope) such as thisTeflon tapeSand, at least two cups worth (for bending the launcher arms)2 1/2" pvc caps (for bending launcher arms, not part of gun)Epoxy for modifying sprinkler valveThread locker (Loctite)
Tools & Safety
Saw, for cutting PVC pipeHeat gun, propane torch, or candle for bending PVCDrill3/16" and 7/16" (or 5/8" see the **note in the pressure chamber section) drill bitsTape measureUtility knifeDremel tool, or similar, with a sanding drumWrench for 1/4" npt hex nippleLarge adjustable wrench or channel-lock pliers, for tightening the trigger valveA compressor or pump capable of attaching to a Schrader tire valve and attaining at least 80 psiSafety glassesLeather gloves
Image Notes1. Pressure chamber section.2. Trigger valve section.
Image Notes1. 2" cap with tire valve inserted.2. 9" length of 2" PVC pipe.
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3. Launcher section. 3. 2" coupler with 2" to 1" bushing in one end, shown with optional pressuregauge.4. 1" slip elbow.5. Length of 1" pipe functions as the pistol grip area. Dry fit until you arrive at alength that you find suitable. Somewhere between 3" and 6" should be sufficient.6. 1" slip to 1" MPT elbow.
Image Notes1. 1" orbit 57461 sprinkler valve. This was a model downloaded from the google3-d library, it doesn't look exactly like the valve.2. Blow gun.3. 1/4" NPT male to male coupler.
Image Notes1. Net holder2. Launcher arms, tractors slide over and onto these.3. Threads into trigger valve.
Step 2: Net Procurement And Math
I ordered my net from the Memphis Net & Twine Company . If you have your own favorite gill net vendor, you can probably order an identical item from them. I have NOfinancial ties to MN&T other than being a satisfied purchaser of their retail products.
Here is the link to the product page on the MN&T website. Below is the exact info from my order information page, shipping is not included in the price. One pound of thisnet (minimum order) will make 7 or possibly 8, 9-1/2 foot square nets.Sku: 263Description: 3 in. sq. mesh, 12 ft. deepQty: 1lbPrice: $12.65
If you would like to try an alternate net part number please read the Alternate Net Substitution section below.
Optional Net Math Section
You may have noticed that the catalog description lists the net as 12 feet deep while I have claimed it is 9-1/2 feet square, why the difference? Let us first deal with ahypothetical net that has 3" mesh and is 3 meshes deep. You might think 3 x 3 equals a 9 inch deep net, but that would be incorrect. Visualize the meshes as diamondsstacked point to point and NOT squares stacked like bricks. Reference Fig 1 and it becomes apparent that the depth of our hypothetical net is nearly 12-3/4 inches. Toextend this example to MN&T sku# 263 , 27 x 4.24 equals 114.48 inches, divide by 12 and we get 9.55 feet deep. So where does MN&T get the 12 foot depth figure?They are building a certain amount of droop, when used in a fishing application the diamonds will be longer vertically than they are wide.
I have included a spreadsheet that will allow you to enter different figures to see what size net you will end up with, and how many nets you will get from a pound of thatparticular net. If the spreadsheet returns a zero for waste material, you may want to subtract one net from the total expected. The default numbers in the spreadsheet arefor MN&T sku# 263 272.
Alternate Net Substitution
I will use MN&T catalog and part numbers in this example, but as long as you know the correct variables, any net vendor should work. Using the spreadsheet isimportant, if you don't own MS excel, consider downloading OpenOffice . An excellent free MS office replacement that will allow you to view and edit the Net Mathspreadsheet.
Please consult Fig 2 or have the spreadsheet open for this example. The top section of the spreadsheet contains a section called Mesh Count Estimator. This will helpyou calculate the mesh count you need to reach a desired net size. In this example I have entered 3.5 (3-1/2" mesh) in the Mesh size cell and 9.5 in the Desired depthcell. This should closely match the sku #263 net's overall size but with a 3-1/2" mesh instead of 3". The computed result, 23.03 appears in the mesh count cell. Asfractional net meshes don't exist, just round to the closest integer, 23 in this case. Next, we will browse through the MN&T catalog for a 3-1/2" mesh net 23 meshesdeep.
Go to the multifilament net section of the MN&T web catalog, then select #208 twine size and browse through the 3-1/2" mesh part numbers to find a net closest to the 23mesh count. Part number 272 fits our specification perfectly.
Now enter all the information from the 272 page into the yellow cells on the Enter line of the net properties section of the spreadsheet. The Square depth cell tells us thisnet will be 9.43' square. This is also the spacing for the knots of your spreader string in step 9 . The Knot cut point shows we need to count 46 knots and then cutbetween knot 46 and 47, the Cut length cell tells us knot 46 should fall at 161" on stretched netting. We can also assume that because the overall weight of the 272 net isslightly less than the 263 net, it should fit fine in the net holder.
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I would advise waiting to build the net holder part of the launcher section if you try any radically different mesh, twine, or overall net sizes. Once you have the netconstructed, fold it up and make sure you have the correct size PVC holder.
Image Notes1. 3" mesh with hypotenuse X.2. Pythagorean theorem, solving for length of hypotenuse X.3. Hypotenuse multiplied by number of meshes deep.4. Result is depth if all meshes are square. In the netgun application they are, asthe net tractors pull equally at all four corners.
File Downloads
Net Math.xls (76 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to 'Net Math.xls']
Step 3: Build The Pressure Chamber
T he pressure chamber is assembled first. It should be allowed to cure a full 24 hours before applying pressure. PVC pipe assembly is simple and is covered in otherinstructables as well as on youtube . A brief refresher on solvent welding PVC pipe. Use in a well ventilated area, make sure both pieces to be assembled are clean andfree of burs, prime both pieces, put glue on both pieces, assemble with a twisting motion and hold for 15 seconds. For brevity's sake, solvent welding will be referred to as"gluing" PVC. The video shows how all the parts are assembled, make sure you have youtube annotation turned on.
Pressure chamber supplies1 1" MPT (M ale P ipe T hread) to 1" slip street elbow1 1" elbow1 2" to 1" reducer bushing1 2" cap1 2" coupler1 foot of 1" pipeMinimum 9" length of 2" pipe1 valve stemPVC primer and cementDrill and 7/16" bit (or 5/8" if you purchased the larger base valve stem)optional 1 pressure gauge
Assembly
Drill the correct size hole in the center of the 2" cap. 7/16" for the smaller (.453" base) valve stem, or 5/8" for the larger (.625" base) valve stem. Pull the valvestem through this hole.Cut a length of 2" pipe at least 9" long. Keep in mind that the longer it is the more time it will take to fill up if you are using a manual air pump.Glue the 2" to 1" reducing bushing into the 2" couplerGlue the 2" cap with tire valve to one end of 2" pipe. Glue the coupler to the other end.Glue a short piece of 1" pipe into the bushing, glue the 1" slip elbow onto that.Cut a piece of 1" pipe for the pistol grip, something between 3" and 6" should work. Glue the 1" MPT street elbow to one end of pistol grip pipe.Glue assembled pistol grip pipe into 1" slip elbow on pressure chamber. Ensure that the threaded fitting aligns with the axis of the pressure chamber and doesn'tpoint off to the right or left.Optional: Drill a hole of slightly smaller diameter than the fitting of the air valve, locate the hole 3/4" into the pipe side (NOT the bushing side) of the 2" coupler.Use the air valve to cut threads into the hole, then thread back in using thread locker on the fitting.
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Image Notes1. 2" cap with tire valve inserted.2. 9" length of 2" PVC pipe.3. 2" coupler with 2" to 1" bushing inserted in one end. Shown with optional pressure gauge installed.4. 1" slip elbow.5. 1" slip to 1" MPT elbow. Threads into the inlet of the trigger valve.6. 1" pipe cut to preferred length. This is the pistol grip area where you will hold the gun while firing.
Step 4: Build The Trigger Valve Assembly
I n this step we will modify an Orbit Model 57461 1" jar top sprinkler valve, making it a pneumatically actuated trigger valve. I found this particular model to have a numberof advantages. It is the cheapest 1" valve I've found. The air valve is installed in the center of the cap allowing easy orientation of the trigger. Finally, the "jar top"construction makes it extremely easy to work on. Here is a link to a page devoted to modifying this exact valve, I left out the safety ball valve in this design. Here is a linkto a visual explanation of how the sprinkler valve works.
Trigger Valve Supplies1 Orbit Model 57461 1" sprinkler valve1 Blow gun or similar1 1/4" NPT pipe/hex nipple, like thisEpoxyTeflon tapeWrenchesDremel or drillThreadlocker
Assembly
Remove solenoid and bleed screw, they will not be needed Fig 1. Save the solenoid for future diabolical inventions.Disassemble valve by unscrewing the "jar" ring. Be careful, as under the top is a spring under tension.Cut, grind, or drill out the center of the top, make sure to leave enough plastic to thread the 1/4" NPT fitting into Fig 2. Grind or cut down the lip of material aroundthe center hole to the level of the ribs Figs 3 & 4. This will allow you to get the fitting deep and tight.Use the 1/4" NPT fitting as a tap for cutting threads into the hole you just made, try to keep it as perpendicular as possible Fig 5.Once you have the threads cut, put Teflon tape on one end of the fitting and thread that into the blow gun Fig 6. Apply some thread locker to the other end of thefitting and tighten the whole assembly into the valve top.You are now ready to epoxy three places. A little dab in the bleed screw hole in the top, a little dab in the bleed hole at the valve outlet, and a good bit of epoxyaround bottom and top of the brass fitting Figs 7 & 8. Try and leave the wrench flats of the fitting exposed and epoxy free in case you need to remove the blowgun at some point.Let the epoxy dry and then reassemble valve. The lever side of the valve should be underneath the outlet of the valve. Make the securing ring is as tight aspossible.
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Image Notes1. 1" orbit 57461 sprinkler valve. This was a model downloaded from the google3-d library, it doesn't look exactly like the valve, please see the pictures.2. Blow gun.3. 1/4" NPT pipe/hex nipple. One end threaded into blow gun, the other into top ofsprinkler valve.
Image Notes1. This is the solenoid, unscrew and save for your junk bin.2. This is the bleed screw, unscrew and discard.3. "Jar ring" unscrew this to disassemble valve. There is a spring underneath,careful not to let it fly out!
Image Notes1. Drill out just this inner section, the remaining hole in the top is just the right sizefor a 1/4" NPT fitting.
Image Notes1. This is the area you want to grind down.
Image Notes Image Notes
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1. This is what the valve top should look like when you are finished. 1. Use 1/4" NPT fitting as a tap to cut threads into the valve top.
Image Notes1. Wrap one end of the fitting in Teflon tape and thread it into the blow gun. Putsome thread locker on the exposed fittings threads, and thread the whole blowgun assembly into the valve top.
Image Notes1. Epoxy here.2. Epoxy here.3. Epoxy around brass fitting on both top and bottom. Try and leave wrenchflats clear of epoxy.
Image Notes1. Pour the most amount of epoxy here. Make sure you don't get it into the fitting!2. Epoxy the bottom side of bleed screw hole as well.
Step 5: Assemble And Test Valve and Pressure Chamber
O nce your pressure chamber has cured for 24 hours, and your trigger valve has cured long enough for the epoxy to reach full strength, you are ready to assemble andtest the trigger valve and pressure chamber.
SuppliesAssembled pressure chamber from step 3Assembled trigger valve from step 4PVC pipe joint compound (pipe dope) such as thisSource of pressurized airWrench or channel lock pliersoptional 5 gallon bucket filled with water
Assembly
Thread your trigger valve onto the pressure chamber for a test fit. The arrows on the side of the valve point in the direction of the airflow, they should be pointingaway from the pressure chamber. The goal is to get the blow gun situated vertically in front of the pistol grip to act as a trigger. Use the channel lock pliers oradjustable wrench to get the trigger valve as tight as possible. If the sprinkler valve bottoms out before the blow gun trigger is vertical, you can file off smallamounts of plastic from the end of the threaded street elbow until it fits perfect.Fill the chamber to 80 psi. Aim in a safe direction and briskly pull the trigger, you should get a loud POP and feel a bit of recoil. Here is a great troubleshootingguide if your valve does anything other than go bang.Once you have a successful test, remove the trigger valve. Apply the pipe joint compound to the street elbow threads and tighten down the valve once more.
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Optional: perform a leak test. Pressurize your chamber to 80 psi. Fill a 5 gallon bucket with water and dip the assembly, look for any bubbles. Tighten and addpipe joint compound to areas with leaks. If the PVC joints are leaking on the pressure chamber, you can apply a vacuum and suck super glue into the voids.
Image Notes1. Assembled pressure chamber and trigger valve. Ready for function and leak testing.
Step 6: Bend Launcher Arms
I n this step we will build a bending jig, and use it to bend four launcher arms to a specific angle. Make sure annotations are turned on when viewing the video.
Launcher arm supplies
4 13" lengths of 1/2" pipe2 1/2" PVC caps DO NOT PRIME OR GLUE THEMSand, at least two cups worthHeat gun, propane torch or candleWood scrap and 3 2" screws to make bending jigLeather gloves
Assembly
Choose a launcher tube angle. A 17 or 19 degree angle will give you longer range but you may need the high performance tractors. A 21 or 23 degree angle willgive you quicker opening shorter range netting, a safer bet if you are going to use soda bottle tractors. Choose and print out one of the PDF templates below.They should be printed in landscape mode on 8 1/2" by 11" paper at 100% scale.Build bending jig. My example bending jig is built on a scrap of 2x4 wood. Hold the template to the surface and put a screw in the pivot position Fig 1. Hold one ofthe arms against the pivot screw and sink screw #2 using the edge of the pipe as a guide Fig 2. Again, with the pipe held against the pivot screw, sink screw #3using the pipe edge as a guide Fig 3.Cut four 13" lengths of 1/2" pipe, these are the launcher arms. Measure and mark, with permanent marker, 3" in from one end of each arm. This mark, the pivotmark, will indicate where to heat the pipe for bending, and indicate the point to line up with the pivot screw of the bending jig.Bend the launcher arms. Tap in place, but DO NOT GLUE, a 1/2" cap on end of the arm. Fill pipe with sand, and tamp to get as tightly packed as possible Fig 4.Fill the second 1/2" cap half full with sand and tap on the open end of the arm. The sand keeps the pipe from kinking. With both caps on the pipe the sandshouldn't slosh when shaken, if it does, add more sand. Put on leather gloves and heat arm as locally as possible on the pivot mark. Rotate the pipe rapidly foreven heating and to prevent blistering the pipe. The arm is ready for bending when it will sag under its own weight held horizontally. Align pivot mark with pivotscrew, the remaining short length should be captured by screw #2, immediately bend longer length of pipe over and lodge against screw #3. Allow to cool on thejig, if PVC is removed while it is still warm it will begin to straighten and lose the correct angle. Once PVC is room temp, remove from jig, remove both caps, andpour out the sand. The heating can also be accomplished with a candle, have a look at robert's instructable step #3. Both tk4717 and ome33 had good resultswith the candle technique.
Repeat for the remaining three arms.
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Image Notes1. Model of the bending jig.
Image Notes1. Sink the pivot screw.
Image Notes1. Sink screw #2 using the edge of 1/2" pipe as a guide.
Image Notes1. Sink screw #3, again use the edge of 1/2" pipe as a guide.
Image Notes1. PVC pipe filled with sand. Fill the cap about half full as well. The tube should bepacked so tightly that the sand doesn't "slosh" around inside.
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File Downloads
17 degree.pdf ((612x792) 201 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to '17 degree.pdf']
19 degree.pdf ((612x792) 172 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to '19 degree.pdf']
21 degree.pdf ((612x792) 210 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to '21 degree.pdf']
23 degree.pdf ((612x792) 216 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to '23 degree.pdf']
Step 7: Build Launcher Assembly
I n this step we will build the launcher assembly. When finished, the whole assembly is threaded into the outlet side of the trigger valve assembly. No pipe dope or Teflontape is needed as this section of the gun isn't holding pressure, the air from the pressure chamber will only be present for an instant so small leaks aren't a problem. Forthat matter, just line up the PVC parts that need to be assembled and push together, don't bother twisting, as proper alignment is paramount for this section. It is helpfulto use a good bit of glue as this gives you a few more seconds to tweak the alignment before it sets, just have some towels handy to wipe up the excess that is squeezedout.
Launcher assembly supplies
4 bent launcher arms from step 61 1/2" cross2 1/2" tee4 1/2" street elbows4 1-1/2" pieces of 1/2" pipe the coupler joiners1 1-1/2" pipe 9" long1 1-1/2" coupler** 1 1-1/2" to 1/2" reducing bushings** 1" MPT to 1/2" slipPVC primer and glueA nickelA drill and 3/16" bit
** these transitions usually can't be made with one adapter, just make sure the starting and ending measurements are correct.
Assembly
Fig 1 is a view of all the components needed for this step.Assemble and glue the adapters needed to go from 1" MPT fitting to 1/2" slip. Glue this to the 1/2" cross, using one coupler joiner.Glue one 1/2" tee perpendicular to the axis of the cross with a coupler joiner. Repeat for the other side.Glue the 1-1/2" coupler to the 9" length of 1-1/2" pipe. Glue the bushings needed to go from 1 1/2" pipe to 1/2". Drill a 3/16" hole in the center of the nickel andforce it into the 1/2" bushing that is at the base of the net holder. This nickel is an air flow restrictor, it allows a little bit of air in to the net holder to assist with netdeployment. Pin this nickel in place by gluing in a coupler joiner. Glue net holder assembly to cross.At this point I would NOT glue the street elbows into the tees, or the launcher arms into the elbows. Line up the street elbows by sighting down the launcher armas in Fig 2, Figs 3 and 4 show incorrect alignment. Once aligned, firmly tap the street elbows on the launcher arms and then tap those into the four tee outlets.This will allow you to adjust the angles, or replace the launcher arms, before final gluing.Align the arms such that the bottom two are parallel with the net holder tube. The top two arms should be twice the angle of your launcher arms. Example, if youused 19 degree launcher arms, the upper two arms should be at an angle of 38 degrees relative to the lower arms.Thread the launcher assembly onto the trigger valve/pressure chamber assembly from step 5, horizontal launcher arms down, angled arms up.
http://www.instructables.com/id/Build-A-Net-Gun/
Image Notes1. Launcher arms from step 62. 1/2" cross3. Nickel with 3/16" hole in the center.4. two 1/2" tees5. four 1/2" street elbows6. ** 1" MPT to 3/4" slip, 3/4" to 1/2" bushing.7. 9" length of 1-1/2" pipe.8. 1-1/2" coupler9. ** 1-1/2" to 3/4" bushing, 3/4" bushing to 1/2" bushing.10. four 1 1/2" lengths of 1/2" pipe, one for each side of the cross. These are thecoupler joiners.
Image Notes1. Correctly aligned street elbow, relative to launcher arm. All four should looklike this.
Image Notes1. Incorrectly aligned street elbow.
http://www.instructables.com/id/Build-A-Net-Gun/
Image Notes1. Incorrectly aligned street elbow.
Step 8: Assemble Tractors
T ractors are what slip on to the launcher arms and are propelled with compressed air to pull the net outward. You can build two kinds of tractors. The simplest are justfour empty soda bottles. They must be bottles that were used for a carbonated beverage as they were designed to withstand pressure. Other bottles, especially waterbottles, are much flimsier and likely to burst. The bottles can be filled with a little bit of hot glue, silicon adhesive, or wax to give them a bit more momentum. The sodabottle tractors are free, nearly indestructible, but suffer slightly shorter range. The high performance tractors are more efficient, due to lower internal volume, so havegreater range. They are a bit more fragile, SDR-21 (Class 200) PVC pipe may be hard to locate, and they take a little more time to fabricate.
Tractor supplies
4 per net 16 or 20oz carbonated soda bottlesHot glue/silicone sealant/wax to pour in bottles to add weightOptional additional items needed for high performance net tractors4 per net 3/4" couplers4 per net 3/4" caps4 per net 8" lengths of SDR-21 (Class 200) 3/4" thinwall PVC note: regular 3/4" SCH-40 will NOT work!4 per net 12" lengths of non-adhesive 1" ID foam pipe insulationSuper glueUtility knifeDremel with sanding drum
Assembly
When selecting soda bottles I would advise digging through a recycle bin with a launcher arm in hand. You want a bottle that slips over the launcher arm, and,ideally, will not slide off under its own weight. Make sure the bottles are identical volume, don't mix in a 16 oz bottle with three 20 oz.For the soda bottle tractors, there is very little assembly. You may want to test your net gun with unweighted bottles, as you can always add weight later. Use ascale, or melt/pour identical pre-measured amounts into each bottle. I don't recommend adding more than 40 grams to each bottle.For the high performance tractors, begin by cutting the necks off of the 4 soda bottles Fig 1. Use the Dremel tool to sand down the threads Fig 2 so the neck canbe pushed into one end of a 3/4" coupler. Once it fits snugly, super glue in place Fig 3.Take the 8" lengths of 3/4" SDR-21 (Class 200) and glue the soda neck couplers on one end and a 3/4" cap on the other Fig 4.Cut four 12" lengths of pipe insulation. These will be slipped over the net tractors leaving 2-3 inches of cushion at the end . This will protect the tractor fromshattering if it hits the ground. It will also minimize damage if the tractor accidentally hits something valuable, like a car, plasma TV, or a cranium. Wait until thetractors are tied to the net (next step) before putting on the insulation.
http://www.instructables.com/id/Build-A-Net-Gun/
Image Notes1. 3/4" coupler with soda bottle neck in one end.2. 3/4" SDR-21(Class 200) thin wall PVC. SCH-40 will NOT work as it won't slipover 1/2" PVC. This is the ONLY component that utilizes SDR-21.3. 3/4" PVC cap,4. High performance net tractor.
Image Notes1. Cut the neck off the soda bottle
Image Notes1. Grind the threads off the bottle top so it will fit snugly in the 3/4" coupler. Use ascrap of 1/2" PVC to hold the cap.
Image Notes1. Super glue the neck into one end of the 3/4" coupler.
Image Notes
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1. 8" length of SDR-21 3/4" pipe.2. 3/4" cap.3. 3/4" coupler with bottle neck in one end.4. Completed tractor. You need four per net.
Step 9: Assemble Net
A single net will be cut from the large net you ordered. We will build a net spreader, a string that runs the perimeter of the net and pulls it evenly into a square. Thetractors are tied to each corner, through a loop in the spreader string, and a loop in the corner mesh of the net. This step involves a little knot work, I use the overhandloop , the bowline , and the double fisherman's bend .
All of the dimensions in this step relate to MN&T sku# 263, if you use a different number you will have to change the following three dimensions.Substitute the Knot cut point value from the net math spreadsheet instead of knot 54.Substitute the Cut length value from the net math spreadsheet for the 162" value.Substitute the Square depth value from the net math spreadsheet as the overhand knot spacing for the net spreader string, instead of 9.55'.
Net supplies
4 tractors from step 81lb Memphis Net and Twine sku# 263OR a substitute net computed using the net math spreadsheet in step 2At least 50' of nylon mason's twine (#15 or smaller), kite string, or some other thin durable rope. This will be the spreader stringUtility knife4 zip ties
Assembly
You will receive a pound of net in a plastic bag. The net is pulled taught and wound into the bag like a rope. Find the free end and count off 54 knots and then cutbetween knots 54 and 55 Fig 1. The 54th knot should land at 162" Fig 2.Take your spreader string and measure 5' and tie an overhand loop. Tie three more overhand loops every 9 foot 6 inches. Leave another 5' of string after thefourth knot and cut. You should end up with 4 overhand loops evenly spaced with 5' of free string at either end Fig 3.Spread your net out in an area where it can lay flat and as square as possible. Tie an overhand loop in the corner of each corner mesh of the net.Weave the spreader string through the rim meshes of the net Fig 4. A spreader string overhand loop should line up with each net corner overhand loop Fig 5. The5 foot 'tails' you left on the spreader string should meet in the middle of the remaining side. Measure a length of 9' 6" on this side and tie a double fisherman'sbend in the middle Fig 6, cut off excess string.Cut four 2' lengths of string, these will be the tractor strings. Tie one end of the tractor string by making a bowline that passes through both the spreader loop andmesh loop Fig 7. Tie a second bowline at the other end of the tractor string, try and end up with 16" from bowline to bowline. Zip tie the free bowline to the bottleneck or the PVC tractor body Fig 8. You can try tying a knot here but I have yet to find one that holds well.If you built the high performance tractors, put the pipe insulation on now. Slide the insulation until it completely covers the tractor Fig 9. Make sure to leave 2-3" offoam at the cap end of each tractor to act as a shock absorber.
Image Notes1. Knot 54 lands at 162"2. Cut here, in between knots 54 and 55.
Image Notes1. Severed between knot 54 and 55.
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Image Notes1. Weave spreader string in an over under fashion through rim of net.
Image Notes1. Overhand loop tied in corner of net.2. Overhand loop tied in the spreader string.
Image Notes1. The double fishermans bend, tied at the ends of the spreader string "tails."Should fall in the center of one side of the net.
Image Notes1. Tractor string bowline tied through both the spreader and net overhand loops.One at each corner, four total.
Image Notes1. Tractor string bowline, zip tied to tractor.
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Image Notes1. 12" length of 1" ID pipe insulation slipped over tractor.
Step 10: Loading And Firing The Netgun
N ow for the fun part. Please be safe in this step. If the launcher arms aren't glued, there is a chance they will fly off during firing, so make sure any spectators are behindyou. Only load the net gun when there is NO pressure in the chamber. It is helpful to have an assistant when laying out and untangling the net.
Firing and reloading supplies
Assembled netgunAssembled netOpen area, preferably outsideCompressed air source
Lay net on ground in a square, pick a clean area, as getting leaves or other debris in the net will keep it from deploying correctly. Pick two tractors, hold themtogether, these are the tops. Walk the tops across the net so they are in between the other two tractors, these outside two are now the bottoms. Move the tractorstogether so they are in a row touching sides.
Starting at the base of the tractors, pull the net into a rope-like tube. Begin at the tip of this tube (farthest from the tractors), grab a 6-8" handful of net and foldback and forth in a zig zag fashion until you are up to the tractor strings. Do NOT keep folding in the same direction, rolling the net will keep it from deployingcorrectly.At the end of the zig zag fold you will end up with an 8 inch, or so, bundle of net. Smooth this bundle out, and insert into the net holder, it will fit snugly.Remember your top and bottom tractor order. Working left to right the first tractor slips on the bottom left launcher arm, second on the top left, third on the topright, and the fourth on the lower right.
Pressurize net gun to 80psi. You should have a at least 30 feet of downrange space free of anything that the net might get entangled in. Keep any spectatorsbehind you in case an unglued launcher arm flies off.Aim net gun. Visualize yourself at the point of a skewed four sided pyramid Fig 1. The two lower launcher arms fire horizontally and outward, the upper pull up andout, your prey will be ensnared in the base of the pyramid. Pull the trigger. If everything goes well the net will be pulled into a square somewhere between 12' and25' feet in front of you. Consult the troubleshooting tips (below) if net doesn't deploy as desired.
Once you are satisfied with the net deployment, glue your launcher arms in place. Make alignment marks with indelible marker or tape before disassembly, youwill then have good alignment references when you glue it back together.If you decide to paint your net gun, do not paint the launcher arms. Even a thin layer of paint will cause the tractors to stick.
Troubleshooting
Net deployed in a horizontal rectangle, not square. Add more up angle to the top launcher arms.Net deployed in a vertical rectangle, not square. Reduce the up angle of the top launcher arms.Net deployed like a big X, not a square. Caused by putting a tractor on the incorrect arm during the loading sequence. Make absolutely sure you keep the tractorsin the correct order, put marks on them if it helps.Net never really opened up at all. Caused by debris in the net , wet net, or poor folding technique. May also be caused by low pressure due to air leaking out whilewaiting to fire.launcher arm flew off. Many possible causes.
Make sure the launcher arms are firmly tapped into the tees.Too much weight in soda bottle tractor(s) causing excessive back pressure. Try starting with empty bottles.
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Sticking tractor(s), make sure the tractors can move freely on the launcher arms. If one or more seem to be stuck, correct problem by replacing tractor or defectivelauncher arm.Too high pressure, start low (70-80psi) and then work up.
Step 11: Et cetera
T hanks for all the positive responses so far. I will post updates to the build and attachments here. I came up with the safety after negligently discharging a net while fillingthe pressure chamber. It is so easy to make, every responsible net gun owner should have one. I developed the tennis ball attachment while working on an older net gundesign that had a 2" net holder, it is a lot of fun for the $3 it costs to make.
Mechanical Trigger Safety
A very simple mechanical safety that will prevent the net gun from firing in the event the trigger is unintentionally actuated.
Supplies
Scrap 1/2" pvc pipeSmall rubber band
Assembly
Cut a short length of 1/2" pipe, probably between 1/4" and 3/8", it will depend on the specifics of the blow gun. It needs to fit under the blow gun handle and bethick enough to prevent the handle from depressing the valve underneath. You made need to cut a wedge out of one side of the ring to allow it to slip under thehandle.Loop rubber band around one end of ring, and through itself. Take the free loop of the rubber band and slide onto the body of the blow gun valve.To put ON SAFE, slide ring around brass valve underneath lever Fig 1. To take OFF SAFE, slide ring down and out of the way of valve and lever Fig 2.
Tennis Ball Launcher
The inside diameter of a 2" PVC coupler fits a tennis ball perfectly. If you own a ball chasing canine, this will forever associate the bang of compressed air with the joy of
http://www.instructables.com/id/Build-A-Net-Gun/
the chase.
Supplies
1 1" slip to 1" MPT adapter1 2" coupler1 2" to 1" reducing bushing2" length of 1" PVC pipe (scrap from pressure chamber assembly)At least one tennis ballPVC primer and cement
Assembly
Fig 3 is a view of all the components needed for this attachment.Glue the bushing into the coupler.Glue the 1" pipe into the slip end of the of the 1" MPT adapter.Glue the exposed 1" pipe from the MPT adapter into the bushing. Let set for 24 hours.Unscrew and remove the net attachment, and thread on the tennis ball attachment. With tennis ball on the ground push the launcher attachment over the tennisball until it is firmly seated Fig 4.Pressurize and fire. Repeat as necessary. If you have a slobbery dog Fig 5 you will appreciate not having to touch the drool covered ball.
updated
Image Notes1. On safe position. Small ring of PVC is preventing the blow gun lever fromdepressing the release valve.2. Small rubber band, looped around body of blow gun.
Image Notes1. Off safe. Blow gun is free to operate normally.2. This particular blow gun needed a small wedge cut from the ring. The othertwo I built did not. It depends on your particular model.
Image Notes1. 2" PVC coupler.2. 2" to 1" slip reducing bushing3. 2" length of 1" PVC pipe.4. 1" slip to 1" MPT adapter.
Image Notes1. Tennis ball launching attachment. Loaded and ready to go.
http://www.instructables.com/id/Build-A-Net-Gun/
Image Notes1. Slobbery ball chaser. AKA Colby.
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Comments
50 comments Add Comment view all 634 comments
Lokisgodhi says: Sep 26, 2012. 5:04 PM REPLYI think the tennis ball launcher is a better use for this project.
How many times are going to be able to use the hey before A.) Your younger sibling complains to your parents and they either take it away or beat your ass.
Or B.) Your pets start run away and hiding every time they see this.
====================================================
Regarding the debate regarding the use of PVC pipe to construct this.
Has the author thought about constructing this of brass tubing and parts,, soldering the pieces together in the same manner as plumbing? The goal being astronger unit.
arty817 says: Aug 7, 2012. 3:27 PM REPLYWhen i blow into the sprinkler valve AWAY from the presure chamber by the arrows it still lets air come out and when i pull the blow gun it lets a bit more airthan there already is! do you now why?
arty817 says: Aug 7, 2012. 3:23 PM REPLYHello i want to say this is wicked allready half way done but you see crispyjones, I live in Australia and we don't use inches like where you live, americaprobably so i wanted to ask what egsact moddle of the valve stem 453" can you please convert the inches in the metric system and tell me what egsacemoddle to buy? or can you send me another link of what valve stem you bought PLEASE PLEASE PLAESE thanks:)
bfk says: Jun 22, 2012. 10:34 AM REPLYLove this instructable, but I have to ask... How did you get the moving image for your initial photo?
That... Is... Awesome.
http://www.instructables.com/id/Build-A-Net-Gun/
crispyjones says: Jun 24, 2012. 10:17 PM REPLYThank you. It's an animated .gif, if I remember correctly I used UnFREEz to make it. Remember, animated gifs must be used in moderation and withcaution lest you end up with Home Simpson's website http://homerswebpage.com/.
Nicktv says: Jun 20, 2012. 1:03 PM REPLYFeel like Jamie Hyneman
its_me says: Jan 4, 2009. 6:26 PM REPLYhehe, you used pythagoras theorm, nice. :)
joshlosh says: Jan 6, 2009. 12:30 PM REPLYWhat's up with this ABS talk? Are you an ABS sales rep? Let it go. Nobody is going to pressurize this to 800 psi. If they do they're not following thedesign. Besides, I'm pretty sure the joints or the valve would go out long before the pvc shattered. And good luck tracking down all this in ABS at yourlocal Home Depot.
PwnimusPrime says: Mar 28, 2009. 12:23 PM REPLYI built a potato cannon out of ABS, and all the parts were purchased at Home Depot. I agree that ABS is a bit of overkill, but Home Depot actually hasevery item he lists.
engineering wizard says: Apr 16, 2012. 11:07 PM REPLYi agree i made one that used propane to shoot the potato instead of it shattering it just melted the seal of the plug oops my bad T-T
Da Person who plays paintball. says: Mar 22, 2012. 10:18 AM REPLYWould it be possible to use a paintball tank to power it.(my question mark is finnicky)
I mean, most tanks can be adjusted to have a low output.
tvane1225 says: Dec 18, 2011. 2:12 PM REPLYhow i met my girlfriend
ChuckmasterFlex says: Mar 12, 2012. 8:17 AM REPLYhaha love it
ktung says: Jul 15, 2011. 4:30 PM REPLYwhere can I buy all the materials ?
hunter55 says: Aug 7, 2011. 2:34 PM REPLYhome depot tracktor supply harber frait autozone
ChuckmasterFlex says: Mar 12, 2012. 8:17 AM REPLY*TRACTOR Supply; Harbor Freight. Good grief.
JRFrank73 says: Jul 30, 2011. 8:28 PM REPLYi purchased most of the PVC at home depot, the sprinkler valve at homedepot.com, thinwall PVC at a plumbing store, and the psi gauge and valve stemat autozone.
Dnorton says: May 31, 2009. 5:43 PM REPLYHere is where it is leaking. It is passing the diaphragm and out the valve outlet but I cleaned it as well like the troubleshooting guide said and it made nodifference. Is there anything else it could be?
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Dnorton says: May 31, 2009. 5:45 PM REPLYOops wrong image but the inner ring that the diaphragm seals is where it is leaking.
crispyjones says: May 31, 2009. 7:30 PM REPLYThe metal tube/guide rod in the center is connected to the nipple in the middle of the outlet port, lower left pic indicated with the pencil. Make sure thisis sealed, you may have a small imperfection in the epoxy that is allowing air to escape. This seems like the most likely culprit. A second thing Inotice, and maybe you took it out for the picture, is you are missing a plastic ring. The white ring in the upper right pic (yours may be black) fitsunderneath the diaphragm. The upper left pic is a taken apart view in order of reassembly left to right, it shows the ring installed. Make sure you havethe valve oriented correctly relative to the pressure chamber. The arrows point to the outlet and away from the pressure chamber and towards thelauncher section. Let me know how you make out.
kingcole816 says: Mar 2, 2012. 8:41 AM REPLYMy valve is leaking air through the outlet and won't hold any pressure. My first inclination was that the diaphragm was defective, but i replaced itand I'm still having the same issue. My valve doesn't have the bleed hole in the outlet port, so I'm wondering if that could be creating the pressureissue. It still has the open notch that is connected to the bleed hole, but the hole itself isn't there. It's the model you recommended, but I'mworking with it years after you wrote the article so they may have redesigned. Hopefully you still check this forum because I *really* want to finishthis thing
crispyjones says: Mar 2, 2012. 9:04 PM REPLYMake certain that the valve is oriented in the correct direction, the arrows on the inlet and outlet ports should be pointing away from thepressure chamber. I am assuming the valve still has the metal tube going through the center of the diaphragm. This tube has to gosomewhere, blow in it, if air comes out the "notch" than you need to plug wherever it is escaping. If it seems like the air is going in thepressure chamber, then you absolutely have the valve on backwards. It might be easier to simply drizzle epoxy into the metal tube directly,you just have to be careful to clean the outside surface of the tube so the diaphragm can slide freely. Good luck.
Nobahd says: Feb 23, 2012. 12:56 PM REPLYPLEASE READ PPL!! word to the wise coming from a plumber of 6 years DO NOT USE PVC. pvc is the reason kids blow there fingers off building potatocannons its not ment for this type of use , use schedule 40 ABS just as cheap and you wont get hurt AGAIN SPECIALLY FOR THOSE KIDS THAT BUILDTHIS TYPE OF STUFF BEHIND THERE PARENTS BACKS AND END UP GETTING HURT IVE SEEN AND HEARD IT MANY TIMES !!! DO NOT USEPVC !!! i realize pvc is "rated" over 100 psi but just because a test pipe at the factory could handle it does not mean all pvc pipe made will be able to take thepressure and thats how ppl get hurt always use ABS
crispyjones says: Feb 26, 2012. 10:52 AM REPLYStep 1 explicitly states that this project uses PVC in a non-approved manner. If that bothers you, don't make this project.
Please link to the "just as cheap" pressure rated ABS. You are probably thinking of DWV (drain waste vent) cell-core ABS that is explicitly is labeled "notfor pressure." In that case you are just substituting a different non-approved pipe for PVC.
I think you also misunderstand the "how people get hurt." The lowest pressure rating in this project is the 2" pressure chamber at 280psi. The problemisn't PVC pressure rating, though it would be for DWV ABS. PVC splinters when broken, if it is pressurized with gas, which stores kinetic energy like aspring, those splinters go flying, ouch. PVC is approved for fluids because a hydraulic failure will not end up with with bits flying everywhere. This is whypneumatic cylinders like fire extinguishers and SCUBA tanks are tested hydraulically by "hydro-testing." Again, it is hard to beat this video/discussionhttp://www.crazybuilders.com/item.php?id=000010&type=project_section&title=blast_box I link to in the first step.
http://www.instructables.com/id/Build-A-Net-Gun/
joeyboi586 says: Feb 22, 2012. 10:44 AM REPLYi know this is my fourth time posting but i really need help i cant find net anywhere i cant find bird net at any of the home depots and i've seen pond nettignbut i think that holes are to small i just really need help from where i can buy th enet other than online somewhere i can pick it up like gander mountain loweshome depot walmart please its all i need to finish this project and i really want to finish
joeyboi586 says: Feb 20, 2012. 2:02 PM REPLYsorry for the multiple comments but for the tractors can you use sdr 25 or is sdr 21 required
crispyjones says: Feb 20, 2012. 2:39 PM REPLYNo problem. I am not sure what sdr 25 is, it isn't even listed here, you just need to make sure its ID is larger than the OD of 1/2" pvc, about .840". As foranother place to buy nets, I really don't know. I've been happy with Memphis Net and Twine, they are willing to sell small amounts of what wouldnormally be a bulk product, I don't plan on buying anywhere else. I am not sure where you need your net shipped but UPS ground for a pound of net willlikely be the same whoever you order from.
joeyboi586 says: Feb 20, 2012. 1:46 PM REPLYwould you have a link to a website that excepts pay pal with a net that is correct
joeyboi586 says: Feb 20, 2012. 1:44 PM REPLYfor the net could you give me a link for amazon cause i don't want to put my credit card on that website plus shipping is very expensive or a link from awebsite that excepts paypal
redwizard87 says: Feb 4, 2012. 9:43 PM REPLYdoes anyone have a pic on what the blow gun should look like the link dosent work anymore
the purple panda says: Jan 5, 2012. 2:30 PM REPLYThanks for the messages. I got only one more question for right now. how far does the t.ennis ball fly? Thanks so much for the anwsers to!
tu eres muy muy simpatico.
the purple panda says: Jan 4, 2012. 2:25 PM REPLYjust got done with the net gun took me three days to build it. we have been launching it at 75 PSI. but whats the most you would put in it with out itexploding?
crispyjones says: Jan 4, 2012. 6:32 PM REPLYI never put over a 100 psi in mine, that is less than half the rated pressure of most SCH40 2" pipe. Once you find a pressure that launches the net withgood consistency you won't get much improvement adding even more pressure. The range is more a function of the size of the net and the angle of thearms, not so much pressure.
the purple panda says: Jan 3, 2012. 3:39 PM REPLYA another question sorry. There are diffrent a attehments for this. there is the net gun one and the tennis ball one. but how long does the tennis ball fly?
the purple panda says: Jan 3, 2012. 3:28 PM REPLYcrispyjones, thank you very much! By the way awsome project it will make my son very happy. : )
the purple panda says: Jan 2, 2012. 3:32 PM REPLYa really i need some one to tell me please/ I have been waiting for some one to type back my last two messages. I have all the pieces and now I'v been stuckfor a month now. Please someone read my two messages and anwser then if you can.
crispyjones says: Jan 2, 2012. 4:25 PM REPLYAnd why do you not wnat to get 3/4" SCH-40 for the tractors,will they not fit?
Correct sch40 will not fit, just like it says in Step 8.
Do you need a 1/4" ball valve
No, you do not need a 1/4" ball valve.
black hole says: Dec 18, 2011. 3:15 PM REPLYHandy for little brothers running off with your money. ; )
http://www.instructables.com/id/Build-A-Net-Gun/
the purple panda says: Dec 11, 2011. 10:28 AM REPLYAnd why do you not wnat to get 3/4" SCH-40 for the tractors,will they not fit?
the purple panda says: Dec 11, 2011. 10:14 AM REPLYA dude awsome. Im building one and i dont get one thing.Do you need a 1/4" ball valve? Or is that to some other project of yours?
1dog789 says: Dec 1, 2011. 9:27 AM REPLYEPIC XD
MeGravity says: Jan 10, 2011. 8:05 AM REPLYWhat's the used CAD package... looks lovely. I have to permit that I didn't read through the whole article so far ;-)Thx
jmcconnell5 says: Nov 4, 2011. 3:11 PM REPLYit was Google Sketchup
1dog789 says: Dec 1, 2011. 9:27 AM REPLYi have that!!!
stevenh429 says: Nov 14, 2011. 5:19 PM REPLYdumb question: would this work?
http://www.homedepot.com/h_d1/N-5yc1v/R-100098062/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
crispyjones says: Nov 14, 2011. 6:41 PM REPLYProbably? Without taking one apart, which I haven't, I won't be able to give you any specifics. You should see if anyone at spudfiles has made thatmodel work.
jmcconnell5 says: Nov 4, 2011. 3:13 PM REPLYWhat sort of 2" coupler are you using? I couldn't get an ABS 2" coupler to fit a tennis ball, in fact the tennis ball was bigger than the OD of the coupler!
k.bipin says: Sep 9, 2011. 6:02 AM REPLYcan you tell me what is the 3D modelling software you used to put up the 3D images??? i want to know pls let me know...
crispyjones says: Sep 9, 2011. 5:42 PM REPLYGoogle Sketchup
pingpongplaya911 says: Jul 10, 2010. 7:09 PM REPLYHow did you manage to get your valve stem through the hole? The .453 stem just seems too big for the 7/16" hole I drilled. Mine says " .453" RIM HOLE 1-1/4" LONG". Is that any different than the stem you used?
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