Introduction: Airsoft Anti-Aircraft Style Coaxial PVC Launcher

Picture of Airsoft Anti-Aircraft Style Coaxial PVC Launcher
Disclaimer: The author is not responsible for any injuries related to or having to do with this device. The author is also not responsible for any property damage caused by this device. Use at your own risk!

Warning: It is specifically against manufacturer recommendations to use PVC to contain pressurized air. These instructions are to be used at your own risk.

Welcome to my attempt at building an anti-aircraft style coaxial PVC launcher. This launcher will be purposed for use in airsoft/military simulation games. The base cannon design was found on another site and I see that the creator also has an instructable posted here. Please feel free to follow or reference his instructions just be aware of my modifications to the firing and filling mechanisms.



Parts:
(2) 3 inch slip coupling
(1) 3 inch x 2 inch reducer
(1) 2 inch slip x 1 inch female threaded reducer
(1) 3 inch x 2 inch flush reducer
(1) 3 inch slip to male thread adapter
(1) 3 inch slip to female thread adapter
(1) 3 foot section of 3 inch schedule 40 PVC piping
(1) 3 foot section of 2 inch schedule 40 PVC piping
(1) 3 foot section of 1.5 inch schedule 40 PVC piping
(1) 3 inch tank to bowl washer (for toilet)
(2) 3 inch steel gas vent T caps
(1) Rainbird 1 inch in-line sprinkler valve
(1) 3/8 inch hose barb to 1/4 inch threaded brass fitting
(2) 1/4 90 degree male to female brass fitting
(2) 1/4 hose barb to 1/4 threaded adapter brass fitting
(1) 1/4 inch brass schrader valve
(1) 160 PSI gauge with 1/4 inch bottom fitting
(3) 1 inch steel self-tapping screws
(1) Sheet of rubber
(2) Small screws
(1) 1.5 Feet of 6x2 cedar
(1) Airgun
(1) ~3 Feet of 1/4 air hose pressure rated to at least 200psi
(2) Small hose clamps for the air hose
(4) 5 inch pipe bands
(1) 4 inch pipe band
(*) Plastic bonding spray paint
(*) Teflon thread tape
(*) Epoxy
(*) PVC Primer/Solvent
(*) PVC Cement
(*) Thread Paste w/ TFE

(optional)
(1) Small hinge
(1) Small clasp
(*) Decals
(*) Acrylic paint: Green, Yellow, Red

Tools:
Bench Grinder
Dremel
Hack saw
Masking or painters tape
Cordless drill
Various drill bits
Pliers
Screw drivers
Strap wrenches
Jig saw
Miter saw
Sander
Sandpaper
Wood clamps



Step 1: Rear of Launcher Chamber

Picture of Rear of Launcher Chamber

Lets get started on the rear of the launcher chamber. If you've never worked with solvent welding/PVC cementing please do some research or perhaps start with a simpler project for your first go. As always please use care to ensure proper ventilation when working with PVC solvent and cement.

PVC Solvent Welding quick tips:
a. Coat both pieces with the PVC primer, cover the areas where they will be joined.
b. Before the primer dries, coat the socket with a thin layer of cement.
c. Before the primer dries, coat the pipe or fitting that will be going into the socket
d. Apply another thin layer of cement to the socket.
e. Quicky join the pieces, try to rotate them a quarter turn as you join them to ensure a good seal.
f. Hold them togther snugly for about 30 seconds to prevent them from pushing out/apart
g. You can handle the parts after about an hour, takes about 8 hours to fully cure/dry in 50-80F, longer in colder temperatures


1. Weld the 3 inch to 2 inch reducer into one end of the 3 inch slip coupling.
2. Weld the 2 inch slip to 1 inch female thread reducer into the 2 inch slip opening.

Step 2: Prepare Flush Reducer

Picture of Prepare Flush Reducer

If your 3 inch to 2 inch flush reducer has a hex lip on the outer edge it needs to be ground flat since we will be using the reducer in the opposite direction.

Picture below shows the lip on mine mostly ground off. I used my bench grinder, you can use that or a sander or a file, although the latter two could take some time.

Step 3: Chamber and Barrel Preparation

Picture of Chamber and Barrel Preparation

1. Weld the 3 foot 3 inch chamber pipe to the 3 inch male thread adapter.
2. Weld the 3 foot 2 inch barrel pipe into the 3 inch to 2 inch flush reducer.

Step 4: Assembling the Chamber

Picture of Assembling the Chamber

Sorry for the bad picture, the instructable I linked to in the intro explains this part in detail.

1. Join the 3 inch female threaded adapter to the 3 inch x 2 inch flush reducer. I screwed the female threaded adapter onto the male threaded adapter to help me join it to the flush reducer. To possbily help explain, the 2 inch barrel we previously joined to the flush reducer is now running down the middle of the chamber in the picture. They can still be separated by unscrewing the threads.

Step 5: Build the Piston

Picture of Build the Piston

1. Grind off the outer lip on both steel gas vent T caps.
2. Sand the inside of both T caps.
3. Sand the bottom of one T cap.
4. Epoxy the two caps together, the one with the sanded bottom goes on top. This will take a decent amount of epoxy 2-3 oz.
5. Let the epoxy set.
6. Cut a piece of rubber to fit inside the face of the top T cap and super glue it down.
7. After the super glue dries you can optionall add epoxy around the edges to hold it down.
8. Wrap the outside of the piston with layers of aluminum tape to create a better fit inside the chamber.
9. Be sure to place the piston into the chamber before sealing the chamber, and remember the front/rubber goes away from the bowl washer.

Step 6: Assembling the Rear of the Chamber

Picture of Assembling the Rear of the Chamber

1. Place a 3 inch tank to bowl washer insde of the rear chamber we assembled earlier.
2. Weld the rear chamber to the chamber, 3 inch pipe to the open end of the 3 inch slip coupling.

Step 7: Preparing the Sprinkler Valve

Picture of Preparing the Sprinkler Valve

Rainbird 1 inch inline valve

1. Disassemble the valve.
2. Cover the holes on the underside of the top with tape.
3. Seal all of the holes with epoxy.
4. When dry remove the tape. I added a little epoxy to the holes on the underside as well to ensure they were sealed. Allow all epoxy to dry.
5. Use a Dremel or hack saw to cut the solendoid and bleeder ports flush with the lid of the valve.
6. Drill a hole in the lid of the sprinkler valve, make sure its slightly smaller than a 1/4 inch 90 degree brass fitting.
7. Place a 3/8 barb to 1/4 thread adapter into the chuck of a 1/2 inch cordless drill. Place the drill in a low speed setting if possible and drive the adapter into the hole this will cut threads into the lid. Remove the 3/8 barb from the lid.
8. Using teflon tape to wrap the threads. Attach a brass 1/4 inch hose barb to 1/4 inch threaded adapter to a 1/4 inch 90 degree brass fitting.
9. Use a 1/4 inch drill bit to drill out the inside of the new 90 degree adapter (drill through the threads of the 1/4 inch barb adapter) to allow for better airflow.
10. Attach the new 90 degree fitting to the lid of the sprinkler valve, again using teflon tape to seal the threads. Point the hose barb straight away from the solenoid port. (even though my initial picture has it facing the solenoid port)
11. Replace the spring taken from the center inside the valve. Use a pliers to open one end of the spring up a little bit (increase its diameter) and fit it around the threads coming through the lid of the valve.
12. Drill holes for the schrader valve and PSI gauge, ensure that the holes stay below the inner diaphram ring (noted in the picture). (Same size as the hole made in the lid) (Also note the locations of the PSI gauge and schrader valve to the flow makrings)
13. Reassemble the sprinkler valve.

Step 8: Barrel Face Preparation

Picture of Barrel Face Preparation

1. Sand the barrel face as smooth as possible to aid in sealing against the piston. I even put a little layer of clear coat spray paint over the face to help seal it.
2. Drill 3 tiny pilot holes equally spaced apart about an 1 inch from the barrel face.
3. Drive a 1 inch self tapping screw into each hole.
4. Adjust the screws to space the barrel so that it is center in the 3 inch chamber.
5. Put epoxy around the screws on the outside of the barrel to seal them since the outside of the barrel will be a wall of the air chamber (coaxial design).

These will also keep projectiles from contacting the piston face.

Step 9: Attach Barrel to Chamber

Picture of Attach Barrel to Chamber

1. Coat the male threads with thread paste.
2. Use a pair of strap wrenches to thread the female adapter with the barrel into the male adapter with the chamber.

Step 10: Attach the Sprinkler Valve to the Cannon

Picture of Attach the Sprinkler Valve to the Cannon

1. Coat the 2 inch long 1 inch diameter nipple with the thread paste.
2. Screw the sprinkler valve to the rear of the cannon. (Ensure the flow of the valve is directed away from the cannon.

Step 11: Valve Shield & Exhaust Port

Picture of Valve Shield & Exhaust Port

1. Cut a 3 inch slip coupling in half with a Dremel or like tool.
2. Sand the ledge around the rear of the cannon.
3. Epoxy half of the slip coupling to the ledge of the cannon.
4. Drill a small hole in rear of the valve opening.
5. Cut a piece of rubber to fit inside the threaded opening on the back of the sprinkler valve.*
6. Screw that rubber piece inside the valve.*
7. Repeat for a rubber flap on the outside of the valve opening.*
(optional)
8. Cut the other half of the slip coupling to fit around the hose barb and schrader valve.
9. Attach it to the side of the epoxy'd half slip coupling with a small hinge.
10. Bend a claps to the angle of the coupling and attach it to the two halves of the coupling.

*Between the rubber flaps is where you can place powders to simulate a launch when the cannon is fired!

Step 12: Trigger Mechanism

Picture of Trigger Mechanism

1. Ensure there is a decent flow through the airgun (some chinese ones are crap)
2. Using a dremel cut off the finger guard and grind it flush.
3. Attach the 1/4 inch 90 degree brass fitting to the 1/4 brass hose barb adapter, be sure to use teflon tape on all of the threads.
4. Use a 1/4 drill bit to drill out the threads from the barb adapter that you can see inside the 90 degree fitting to increase airflow (same as the earlier fitting.
5. Attach the brass to the airgun, again use teflon tape on the threads.
6. Now push one end of the 1/4 air hose onto the trigger mechanism barb and secure it with a small hose clamp. Make sure the screw portion of the clamp is downward towards the airgun.

Step 13: Grips

Picture of Grips

These will involve some imagination and woodsmanship.

1. Cut a 7 inch piece of 6x2 cedar.
2. Fashion a desirable grip design, it helped to lay the airgun mechanism on the block of wood and draw around it.
3. Cut out the grip roughly with a jigsaw.
4. Using a 1/2 inch drill bit and the Dremel with a high speed cutting bit router out a space inside the grip for the trigger mechanism
5. Cut the grip section slightly thinner with a hacksaw
6. Use a Dremel sanding bit to create the finger grooves.
7. Sand it all to taste

I don't have any creation pictures of the front grip (there are some in the final assembly) but the same process was used minus the routering out for a trigger.

Step 14: Sight Mount

Picture of Sight Mount

My design idea came from this site: http://blog.kotarak.net/2011_04_01_archive.html

I used 1/16 aluminum L bar for the outer frame and 1/8 aluminum bar for the hinge and mounting it to the cannon. The piece attached to the cannon simply has a slot cut in it for one of the pipe bands to pass through. The phone is a spare Droid 2 device I had around and the app I use is called Geo Cam there is both a free and paid version. The phone is velcroed to the mount. The hinge is a special bolt I found at Lowe's that has the knob on top and is a #10 bolt. I added a lock washer and two nuts. I put a small screw in the bar attached to the cannon then Dremel cut a small notch in the bar attached to the sight so that it stops the hinge straight open. I drilled a hole for the camera to see through.

Step 15: Mounting the Grips

Picture of Mounting the Grips

Place them to your liking. Use trial and error to find what's most comfortable for you.
1. To mount them use a drill to create slots for the pipe bands to pass through. Be careful on the trigger grip to avoid the airgun and hose assembly. I used 5 inch pipe bands to secure the grips.
2. Cut the air hose to the necessary distance and mount it to the the sprinkler valve with the other small pipe band, ensure that it is taunt.

Be sure to tighten the pipe bands for the grips slowly as they get tight and make sure the wood does not start cracking.

Step 16: Air Line Shield

Picture of Air Line Shield

1. Cut a piece of 1.5 inch pvc piping vertically, not right down the middle but slightly off center so that one half is bigger than the other. I had to get creative with a compound miter saw to get the cut i needed.
2. The smaller rear pice is epoxy'd to the cannon.
3. I started off epoxying the large one and ended up putting a 4 inch pipe band to ensure it stayed secure.

Step 17: Cosmetics

Picture of Cosmetics
I propped the cannon up between two saw horses to paint. Covered the valve assembly with a plastic sack. Covered the trigger and visible airgun parts with painters tape. I covered the whole thing with a base coat of a flat green camo spray paint designed to bond with plastics and then using masking tape once the green was dry and added some black accents. I then added the decals I got from ebay and finished with a coat of flat clear coat to seal everything. I added some acrylic accents to the edge of the PSI gauge: green, yellow, red. I took the sight mount off the cannon at the hinge and painted that black. I then added a small piece of foam and glued it to the cannon where the sight mount swings closed and touches the cannon.

Bullet Bill Decals
Stark Decals


Comments

knight6231a (author)2017-03-15

can i just buy this lol from u

KT Gadget (author)2015-10-11

How is the piston mounted in the pipe? I can't figure out what the function for it is and exactly where it needs to be. I am attempting to upgrade a set of launchers my group has and this build looks to be what we need. Help is appreciated for that step.

hsimo24 (author)KT Gadget2016-08-11

It's "free floating" in the chamber. Best way to put it. The goal is to have it fit close to snug but not too snug. Air needs to pass around the edges of the piston when filling since the tank essentially is around the barrel. The piston gets pressed up against the section of barrel that extends into the chamber and the pressure of the chamber holds it "closed". Then once the sprinkler valve is opened (exhaust) the air to the rear of the piston escapes faster out the rear of the chamber and the air in front of the piston pushes the piston back and the air in the tank then escapes out the barrel. Basically the volume of air behind the piston needs to escape quickly enough or faster than the air in the tank can seep back around the piston and is therefore forced to push the piston back instead.

farrell989 (author)2016-08-11

Can I get som questions answered regarding this build?

hsimo24 (author)farrell9892016-08-11

I can try, it was a while ago. Go for it!

Pyromaniac88 (author)2015-07-02

I can't wait to build one of these and take it to the paintball field. I'd shoot a shotgun load of paintballs to take out as many people as possible. We won't be losing another game!

ruyther.tomich (author)2015-03-22

now that's an awesome launcher!

wulfst (author)2014-06-07

This is absolutely brilliant, and I appreciate you posting an instructable on this. I have been wanting to have an RPG available for airsoft games, and I think this is just the one I want. Thanks!

Masher007 (author)2014-04-28

This is not spam, but a warning. PVC will fail suddenly after a while. This was band member that hurt badly by a T-Shirt launcher explosion.

See the pictures and never use PVC to hold air, Please.

https://fundrazr.com/campaigns/1Zs3c
..

hsimo24 (author)Masher0072014-04-29

There are lots of factors that could cause PVC to fail. Anyone using PVC in such a manner as depicted in this instructable should do research beforehand and assume all risk.

D3LUSI0NAL (author)2013-08-23

Link for the air gun?

hsimo24 (author)D3LUSI0NAL2013-08-26

Don't have one. I just picked up the air gun at a local discount tool store.

Noah Tingey (author)2013-06-12

I love the stark industries label!

zekezane (author)2013-05-02

How much did you spend on this?

hsimo24 (author)zekezane2013-06-12

Really really rough estimate: $200ish.

Gamaguy365 (author)2013-06-11

What is the rough cost of building this? I know depending on store, location, and brand, the final price may vary. I think the Anti-Air Launcher would be pretty neat to add to my arsenal of different launchers ^__^

hsimo24 (author)Gamaguy3652013-06-12

My guesstimate would be so rough I'm not sure its of any value. I'd say in the neighborhood of $200.

okoshima (author)2013-04-14

ideal backup for running recon... pistol? nah rpg baby

arkangel1975 (author)2013-04-08

hehehe like the Stark logo

heh same

ilpug (author)2013-04-08

A very nice build, except to use this in Airsoft would be pretty dangerous.

hsimo24 (author)ilpug2013-04-08

Well we will obviously keep the PSI within reason enough for it to remain safe. I may add a pressure safety valve so it can't be pressurized over a certain point.

About This Instructable

22,507views

169favorites

License:

More by hsimo24:Airsoft Anti-Aircraft Style Coaxial PVC LauncherSimple Tips to Speed up Windows 7 and Windows Vista
Add instructable to: