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 25 feet 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 removed in 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 a tennis 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 are based 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.

Thanks for all your votes in the Craftsman contest, happy netting.  Please check out my slooowly developing website related to netguns at waxedmoustache.com.

Step 1 Materials

Before 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. If the PVC is compromised, by dropping, impact, or other means, it shatters into sharp pieces that are ejected by the pressurized gas. An excellent discussion and demonstration 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 if you 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 are available at auto parts stores. The net is addressed in detail in the next step.

SUPPLIES
All PVC fittings are slip fit unless otherwise noted
All PVC pipe and fittings must be SCH-40 (SCHedule 40) unless otherwise noted
All PVC pipe should have a PSI rating of 200 or greater, absolutely no cell core ABS DWV pipe

• Pressure chamber parts Fig 1

1 1" MPT (Male Pipe Thread) to 1" slip street elbow
1 1" elbow
1 2" to 1" reducer bushing
1 2" cap
1 2" coupler
1 foot of 1" pipe
minimum 9" length of 2" pipe
**1 valve stem, prefer a .453" as it corresponds to the readily available 7/16" drill bit
optional 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 parts Fig 2

1 Orbit Model 57461 1" sprinkler valve
1 Blow gun similar to this
1 1/4" NPT hex nipple, like this

• Bending jig

3 2"(ish) wood screws
Wood scrap for base, a 16" length of 2x4 should work fine

• Launcher section Fig 3

4 13" lengths of 1/2" pipe
1 1/2" cross
2 1/2" tee
4 1/2" street elbows
4 1-1/2" pieces of 1/2" pipe (coupler joiners)
1 1-1/2" pipe 9" long
1 1-1/2" coupler
**1 1-1/2" to 1/2" reducing bushings
** 1 1" MPT to 1/2" slip
1 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 nets
OR a substitute net computed using the net math spreadsheet and instructions in step 2
Nylon mason's twine (#15 or smaller), kite string, or some other thin durable rope
4 per net 16-20oz carbonated soda bottles
4 per net zip ties > 4" long
Hot glue/silicone/wax to pour in bottles to add weight
Optional additional items needed for high performance net tractors
4 per net 3/4" couplers
4 per net 3/4" caps
4 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 primer
PVC safe pipe joint compound (pipe dope) such as this
Teflon tape
Sand, 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 valve
Thread locker (Loctite)

• Tools & Safety

Saw, for cutting PVC pipe
Heat gun, propane torch, or candle for bending PVC
Drill
3/16" and 7/16" (or 5/8" see the **note in the pressure chamber section) drill bits
Tape measure
Utility knife
Dremel tool, or similar, with a sanding drum
Wrench for 1/4" npt hex nipple
Large adjustable wrench or channel-lock pliers, for tightening the trigger valve
A compressor or pump capable of attaching to a Schrader tire valve and attaining at least 80 psi
Safety glasses
Leather gloves

Comments

[the purple panda]

Thanks 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]

just 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 it exploding?

[crispyjones]

I 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 with good 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 the arms, not so much pressure.

[the purple panda]

A 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]

crispyjones, thank you very much! By the way awsome project it will make my son very happy. : )

[the purple panda]

a 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 stuck for a month now. Please someone read my two messages and anwser then if you can.

[crispyjones]

And 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]

Handy for little brothers running off with your money. ; )

[tvane1225]

how i met my girlfriend

[the purple panda]

And why do you not wnat to get 3/4" SCH-40 for the tractors,will they not fit?

[the purple panda]

A 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]

EPIC XD

[MeGravity]

What's the used CAD package... looks lovely. I have to permit that I didn't read through the whole article so far ;-)
Thx

[jmcconnell5]

it was Google Sketchup

[1dog789]

i have that!!!

[stevenh429]

dumb question: would this work?

http://www.homedepot.com/h_d1/N-5yc1v/R-100098062/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

[crispyjones]

Probably? 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 that model work.

[jmcconnell5]

What 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]

can 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]

Google Sketchup

[pingpongplaya911]

How 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?

[pingpongplaya911]

Never mind I got it.

[MafiaGerbil]

Hey, I think I am having the same problem you did. How did you get it in there?

[pingpongplaya911]

You have to pull it extremely hard. I believe I used a pair of pliers and lubricated it with water or something similar. You have to pull it so the notch of the valve comes on the outside of the cap. It may seem impossible, but it's not.

[mosorio borja]

Hi ...
very nice project. : b
what do I have to do if I choose for the 1in. sq. mesh 6 ft. deep #104???
thanks for the help in advance.

[ktung]

where can I buy all the materials ?

[hunter55]

home depot tracktor supply harber frait autozone

[JRFrank73]

i 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 stem at autozone.

[hunter55]

cool but im confuse whats the blowgun for

[tdking3523]

I'm only a 14 year old kid with a few friends, do you think this will be a difficult thing to build on our own? cause I don't want to buy the parts and not be able to make it.
Thanks!

[facilitator476]

ditto, i just turned 15 and the hardest part of doing these things is scrounging for the parts

[JRFrank73]

can anyone give me a shipping estimate on the netting? i live in Pennsylvania. even shipping costs to other states would be helpful, just so i have a basic idea if im going to pay $5 or $20.

[That One Eegit]

How did you do that moving picture?

[dremeldude]

if you wanted the trigger to be more accessible you could substitute the nipple for two barbs and hose.

[ultravark]

Is there any reason that you couldn't replace the tire valve with a schrader valve like this?  It just seems to me that screwing in the schrader valve would be more secure than the snap fit of the tire valve. (Though this is my first pneumatic cannon project, so I could be missing something completely).

[ultravark]

Link didn't work:
http://www.spudtech.com/detail.asp?id=44

[crispyjones]

I stayed away from these for a few reasons. They are usually 1/8" NPT, so you need some adapters to get to anything nominally PVC sized, that adds cost. If you knock against something hard with a rubber tire valve it just bends, I think these will be more likely to snap some plastic off with them. One of my net guns died a similar death when it fell off a railing and the metal pressure gauge snapped off a chunk of the pressure chamber. Also, as long as you drill the correct size hole, the rubber ones are very secure.

In summary, I didn't use them, mainly, because I am cheap, and I think they might make the launcher less durable.

[tinker234]

hey just a thought if i made a metal net added a tazer to it could i knock some one out with this net gun

[DannytheGreat]

thats an awesome idea

[tinker234]

thank you just a thought i hate crime be a nice thing to break up a fight with