Introduction: Build a Net Gun

Picture of 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.

Step 1: Materials

Picture of 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.

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 partsFig 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 partsFig 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 sectionFig 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
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

Step 2: Net Procurement and Math

Picture of 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 NO financial 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 this net (minimum order) will make 7 or possibly 8, 9-1/2 foot square nets.
Sku: 263
Description: 3 in. sq. mesh, 12 ft. deep
Qty: 1lb
Price: $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 a hypothetical 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 diamonds stacked 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. To extend 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 that particular 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 are for MN&T sku #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 is important, 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 Math spreadsheet.

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 help you 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 depth cell. 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. As fractional 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 meshes deep.

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 23 mesh 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 this net 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 cut between 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 is slightly less than the 263 net, it should fit fine in the net holder.

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 net constructed, fold it up and make sure you have the correct size PVC holder.

Step 3: Build the Pressure Chamber

Picture of Build the Pressure Chamber

The 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 other instructables 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 and free 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 supplies
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
PVC primer and cement
Drill and 7/16" bit (or 5/8" if you purchased the larger base valve stem)
optional 1 pressure gauge

  • 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 valve stem 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" coupler
  • Glue 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't point 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.

Step 4: Build the Trigger Valve Assembly

Picture of Build the Trigger Valve Assembly

In 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 number of 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 link to a visual explanation of how the sprinkler valve works.

Trigger Valve Supplies
1 Orbit Model 57461 1" sprinkler valve
1 Blow gun or similar
1 1/4" NPT pipe/hex nipple, like this
Teflon tape
Dremel or drill

  • 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 around the 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 the fitting 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 epoxy around 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 blow gun 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 as possible.

Step 5: Assemble and Test Valve and Pressure Chamber

Picture of Assemble and Test Valve and Pressure Chamber

Once 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 and test the trigger valve and pressure chamber.

Assembled pressure chamber from step 3
Assembled trigger valve from step 4
PVC pipe joint compound (pipe dope) such as this
Source of pressurized air
Wrench or channel lock pliers
optional 5 gallon bucket filled with water

  • 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 pointing away 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 or adjustable 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 small amounts 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 troubleshooting guide 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.
  • 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 add pipe 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.

Step 6: Bend Launcher Arms

Picture of Bend Launcher Arms

In 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" pipe
Sand, at least two cups worth
Heat gun, propane torch or candle
Wood scrap and 3 2" screws to make bending jig
Leather gloves

  • 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 will give 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 of the 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 #3 using 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 pivot mark, 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 sand shouldn'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 for even 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 pivot screw, 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 the jig, 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, and pour 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 results with the candle technique.

  • Repeat for the remaining three arms.

Step 7: Build Launcher Assembly

Picture of Build Launcher Assembly

In 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 Teflon tape 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. For that 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 helpful to 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 squeezed out.

  • Launcher assembly supplies
4 bent launcher arms from step 6
1 1/2" cross
2 1/2" tee
4 1/2" street elbows
4 1-1/2" pieces of 1/2" pipe the coupler joiners
1 1-1/2" pipe 9" long
1 1-1/2" coupler
** 1 1-1/2" to 1/2" reducing bushings
** 1" MPT to 1/2" slip
PVC primer and glue
A nickel
A 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.

  • 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 and force 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 net deployment. 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 arm as 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 you used 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.

Step 8: Assemble Tractors

Picture of Assemble Tractors

Tractors 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 just four empty soda bottles. They must be bottles that were used for a carbonated beverage as they were designed to withstand pressure. Other bottles, especially water bottles, 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 soda bottle tractors are free, nearly indestructible, but suffer slightly shorter range. The high performance tractors are more efficient, due to lower internal volume, so have greater 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 bottles
Hot glue/silicone sealant/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" SCH-40 will NOT work!
4 per net 12" lengths of non-adhesive 1" ID foam pipe insulation
Super glue
Utility knife
Dremel with sanding drum

  • 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 a scale, 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 can be 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 from shattering 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 the tractors are tied to the net (next step) before putting on the insulation.

Step 9: Assemble Net

Picture of 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. The tractors 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 overhand loop, 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 8
1lb Memphis Net and Twine sku# 263
OR a substitute net computed using the net math spreadsheet in step 2
At least 50' of nylon mason's twine (#15 or smaller), kite string, or some other thin durable rope. This will be the spreader string
Utility knife
4 zip ties

  • 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 cut between 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 the fourth 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. The 5 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's bend 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 and mesh 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 bottle neck 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" of foam at the cap end of each tractor to act as a shock absorber.

Step 10: Loading and Firing the Netgun

Picture of Loading and Firing the Netgun

Now 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 behind you. 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 netgun
Assembled net
Open area, preferably outside
Compressed 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 them together, 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 tractors together 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 fold back 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 deploying correctly.
  • 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 top right, 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 spectators behind 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 and out, 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' and 25' 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, you will 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.
  • 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 tractors in 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 while waiting 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.
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 defective launcher arm.
Too high pressure, start low (70-80psi) and then work up.

Step 11: Et Cetera

Picture of Et Cetera

Thanks 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 filling the 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 gun design 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 pipe
Small rubber band


  • 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 be thick 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 the handle.
  • 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 the chase.

  • Supplies
1 1" slip to 1" MPT adapter
1 2" coupler
1 2" to 1" reducing bushing
2" length of 1" PVC pipe (scrap from pressure chamber assembly)
At least one tennis ball
PVC primer and cement


  • 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 tennis ball 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.



jerryrigit (author)2013-03-14

NPT........not NPR.......typo, my bad.

crispyjones (author)jerryrigit2013-03-16

Thanks for sharing, this is what makes Instructables work.

jerryrigit (author)jerryrigit2013-03-14

The red handle is just a 1/4 in. ball valve that was added to act as a safety (don't want any accidental discharges!!) It's in the open position in the photo. The hole to the left is where the solenoid was located. Epoxy the entire bottom of it. take out all the screws, pop off the lid gently with a screw driver, (use notch provided next to where solenoid was). Drill you hole for the 1/4 in. NPT nipple that mounts your blow gun (or a 1/4" ball valve, then blow gun- if desired). When you have the diaphram valve cover off, epoxy your threads from the nipple you inserted into the cover (without getting epoxy into the fitting) and epoxy the little bleed hole as well (small rectangular opening that leads into where the solenoid was located....not totally necessary, but why not since you have the cover off. Let sit for at least 20 min. before charging your gun with pressure. The Orbit valve model #57461 is the one in the photo. Enjoy. Thanks Crispy for the info!

zacksyj (author)2017-12-26

Could you upload the models? I would really like to see them

James Schuler made it! (author)2017-11-15

Hi! I'm trying to build this. I could not find the recommended Sprinkler Valve [darker pic] so I had to use the closest one like it available at the Big Box stores, which is Orbit model # 57465 [lighter pic]. Instructibles says to epoxy the small round hole above the sm square hole, but mine only has a sm sq hole. Any help on this please? Thank you! -James

I am 98% certain that serves the same purpose and you should just fill it in. That square hole is the outlet to a passage that leads to the upper part of the valve, I assume it's a metal pipe like the old one but I can't see. You can confirm by blowing in one end or the other to see where the air comes out.

When uses for its designed purpose (water) the sprinkler valve must vent the water from above the diaphragm after the solenoid has turned on, so it vents it into the outlet water pipe via that passageway. We are modifying it to vent to atmosphere through the air valve instead.

To Whom It May Concern — I suggest adding into the Instructibles: "if using Sprinkler Valve Orbit model # 57465, then epoxy over the small rectangular hole."
Theres my 2 centavos! |-}

You were Right! Did a quick test with my finger covering the hole, pumped it to 40psi, and trigger makes POP! Thank you!

BebeS3 (author)2017-09-22

Does anyone have one of this for sale or is willing to make me one?

BebeS3 (author)2017-09-22

Does anyone have one of these net guns for sale, or is willing to make me one?

the modder (author)2017-09-16

cool dude whats the psi on this gun

TheLoneWanderer (author)2017-03-14

The new show "The White Rabbit Project" used your design on an episode. They used it to take down drones.

Thanks for the heads up. Can't wait for the big royalty check ;)

earlleebird (author)2017-01-17

Fantastic! I didn't have this in time to catch a run away peacock, but I will next time. It made me so mad that he was 10 feet away from me and the only thing I could do was hope he don't fly up into the oak trees, which he did of course. Took three days for him to finally come back home. Not going through that again, Thank you for the design, no way I could afford $1000 for one

crispyjones (author)earlleebird2017-01-17

If you caught a peacock or hen with this net gun I would definitely add the video or picture to my instructable!

swaltersjr (author)crispyjones2017-01-24

Hey Guys, I myself am attempting to build this to assist with rescuing geese and ducks for the rescue i volunteer at. I have the build complete but at the moment im having an issue with pressure. When attempting to fill with air, its just coming straight out and not staying in the chamber behind the almost certain i followed your instructions step by step. The only difference is I am using the model 57661 and not the 57461. If you think that will make a difference I will order one.

swaltersjr (author)swaltersjr2017-01-27

I can say that this thing is a blessing. I have finally gotten it together and fired my few test rounds and it WORKS. I will be sure to post pics/videos of the first bird rescue i do.

Gerhard-JohanW (author)2017-01-24

silicone spray is a great lube for this gun

Flyingbacon95 (author)2016-10-17

and how bout the thing that goes over the pipe to use to fire?

Greywolfg (author)2016-07-31

Hey, buddy. You're a genius :D

FrankC19 made it! (author)2016-06-21

We build lots of launchers for paintball, airsoft and MilSim, and are not allowed to use any with PVC air chambers, or those green orbit valves, anymore (just changed the rules on valves this year)- the had some of those shatter too. Probably was dropped, but they were quick to ban them.
We use CO2, argon, or oxygen tanks, they can had pretty cheap, are indestructable and rated for over 3,000+ psi burst. They need drilled and tapped, but it's all metal and really safe. With a carbon fiber valve, we can go to 150-175 PSI. Double the range and still be safe. Most compressors only go to around 110 PSI anyhow.
We also have push button, and other parts.

crispyjones (author)FrankC192016-06-22

Thanks for ideas FrankC19. Do you have any links to the stuff you build, and I am interested in the carbon fiber valve.

pskvorc (author)2016-06-22


ThomasN31 (author)2016-06-22

This was designed beautifully! Definitely something I'll have to try!

It would be even more awesome if you had an automatic wind-up of the net, so if you miss, you can just hit a button, a motor and string would pull the net back, replace the tractors, charge the tank, and you're ready to go!

RockeyD (author)2016-06-22

normally this top weekly email stuff is really dumb.. this is a something i have wanted for years. i might put time into somthing like this!

Laral (author)2016-06-21

Wow, this is splendid. Just what I need to capture neighbors' or gvt. quad-copters over my yard.

David the R (author)2016-06-21

I can use it to catch my drone when it refuses to come home…...

ElizabethGreene (author)2016-06-21

What application did/do you use to make your cad drawings/models?

thegrendel (author)2016-06-21

Something like this could be of interest to law enforcement. Thanks for the Instructable.

lotus959 (author)2015-10-05

Here's a thought/question: Couldn't one reduce the risk of PVC shards by wrapping all of the appropriate parts with athletic tape or perhaps some other type of tape?


If an impact or other event were to occur that would normally cause the pressurized PVC to shatter, I'm not sure if any reasonable number of layers of tape could actually bolster the PVC enough to help prevent that from happening...or could it? Regardless, assuming that the PVC would indeed shatter, it seems to me that even a few layers of athletic tape would help to reduce the velocity of any shrapnel, and a few more layers might even contain the shards enough to *prevent* them from becoming shrapnel entirely, much in the spirit of laminated safety glass but with the binding layer on the outside.

I like the idea of athletic tape because I have seen projects wrapped carefully in it, and it provides a sleek look and good grip. With safety as the issue at hand, though, I would rather use an ugly tape that would work better than one that is cosmetically superior but functionally inferior.

I have no specific knowledge regarding the engineering involved or the behavior of the materials in question, so all that I can do is to speculate. I would appreciate any thoughts on these questions from anyone who actually knows enough to offer more than my guesswork: (1) Is this idea feasible? (2) Is there another kind of tape (duct tape?) that might work even better than athletic tape? (3) How many layers might it take to reduce significantly the velocity of shrapnel, to prevent flying shrapnel altogether, or (if even possible) to actually strengthen the PVC enough to make it more shatter-resistant?

Great instructable, by the way! I am sorely tempted to set aside the time to make one of these.

105birr105 (author)lotus9592016-06-21

There is always fiberglass cloth impregnated with resin. That is how plastic pressure tanks are made. just saying.

crispyjones (author)lotus9592015-10-09

If I was going to pick a tape I would probably choose duct tape, this is based on instinct and utterly non-scientific. That being said, I've built a few iterations of these things and never used tape. The only hardening I tried was to build an all-coupler version (pictured) of the pressure chamber. Not sure if it is any safer, but it's definitely heavier. I have actually broken one unit (not the all-coupler version) under pressure, it took a 5' fall from my deck railing and hit the ground. It snapped in two at the thin handle part of the pressure chamber, no large explosion of shards. I've fixed the video link in the 1st step but here it is directly

I don't really have a good answer because there isn't one. We're using a piping system not designed for gas pressure to hold a pressurized gas. Out of the gate we've violated the design specs and therefore we are on our own. If you do some experiments let us know how it turns out.

WilhelmG3 (author)2016-05-18

Just the thing. I posted these instructions to a dog rescue site. Hoping that it might be useful in catching skittish strays

elizabetho18 (author)2016-04-14

I have made a version of this gun with a slightly larger pressure chamber, which runs 15mm copper pipe from the trigger mechanism. It pressurises to 100psi very easily, has no leaks, but when I fire it the tractors have a poor range. Any ideas?

crispyjones (author)elizabetho182016-04-14

Cool, I'd love to see a picture. Couple basic things to check.

What kind of range are you getting? I worry less about range and focus more on how the net snaps open, there is only so far a 10' square net pulled by some PVC pipes will go. If it snaps open quickly and evenly then everything is probably good. If the net never really opens fully then you might have an issue.

With just the valve attached (unscrew the launcher section) do you get a loud bang and a bit of recoil when you pull the trigger? If not than your sprinkler valve isn't releasing air fast enough, could be on backwards, could be something jamming the diaphragm, could be a restricted trigger valve, to name a few possibilities.

If your valve is good, check your tractors. Do they slide smoothly off the launcher arms?

Good luck.

elizabetho18 (author)crispyjones2016-04-15

Thanks. I will post a photo … I'm getting about a 5 foot range at the moment. I'll check the things you mentioned, but do you think it could be that there isn't any pipe diameter reduction from the trigger on my version? It's 15mm all the way from the trigger. Thanks again...

crispyjones (author)elizabetho182016-04-15

If it is 15mm between the output of the pressure chamber to the input of the sprinkler valve, then yes, that's likely too small and the cause of the poor range. If you are just talking about 15mm launcher arms, then I am not sure that would be too small. I've only built my netgun using US spec PVC so I honestly don't know how things will behave with different materials and sizes.

DEEJAY642 (author)2015-11-14

WOWOWOWOWOWOWOW this is 1 BIG Instructable. it mustiv taken u ages!!!! by the way very cool idea

CristianC22 (author)2015-10-13

Would you be able to get springs strong enough to build a spring-loaded version of this - for portability?

I would be able to use a cast net in the ocean without spraining my elbow.

It can also (maybe) used to take down drones in a less police involving way than this:

MyronH1 (author)2015-08-09

@ RDmaniac on the end of compressed air tank there is a tire stem -like on a car or bicycle tire .Use a compressor with a tire fitting to fill the tank with compressed air

forqueue (author)2015-07-31

Errrr, there is a reason PVC or CPVC (sch 40 or 60) is not used for air systems and is banned by OSHA. It can SHATTER into small shards, like a hand grenade, with no warning. The psi ratings are for LIQUID. Hate to see it do that next to someones face. Just sayin'...........

CigarSmoker2 (author)2015-07-15

well now I have to build a new barrel for my air cannon to shoot a net. This is just too cool, Batman would be proud. Very impressed with the size of the net that can be fired.

ingpendleton (author)2013-08-26

Which of the MANY comments and corrections of these instructions, which ones do I need to pay most attention to? I am going to make about 40 of these so I really need to know. Thanks for helping.

exex (author)ingpendleton2015-06-24

Are you selling them?

ingpendleton (author)exex2015-06-24

Hello exex.

I plan to use them. I live in the highlands of

central Mexico. I have talked to many witnesses

who have seen pterosaurs (pterodactyls). I plan to use

the net guns to catch one(s). Seriously. John

exex (author)2015-06-24

Epic!!! Btw, 3/4 in cpvc (not a typo - it also hapens to be stronger) fits paintballs well. have fun!!

teamclaussen (author)2015-03-17

Fun to make! Going to modify to take out a pinata this May.

primo.thepitbull1 (author)2015-03-06

Hi, has anyone tried to make one of these using the potato gun hair spray ignition instead of compressed air? It seems like it would work.

caddyb (author)2015-01-27

I'm a bit late to the party but would like to take a few moments to heartily commend your efforts on this instructable. Your work in detailing the plans is " top notch" and I'm quite sure consumed a considerable amount of time, gathering data and drawing all the steps. THANK YOU. As a bird wildlife rescue and rehab volunteer, I have spent a inordinate amount of time trying to capture birds that have been compromised by fishing line and even lures embedded in them. They are injured and need help but are not diminished enough (yet) to easily catch. This net gun will be a real time saver for all that do this kind of work. Our goal is to catch 'em, fix 'em and release 'em as quickly and humanely as can be accomplished. Prolonged attempts to capture are quite stressful for them. This will help a great deal. My construction will begin today and I will be wrestling with a way to "modify" the net gun to utilize a tank of air that will be more suitable in the field as the refill in the field would be tough! Thanks again for your efforts

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