One of the best parts about the Southern Alberta Jamboree a few summers ago was that the water guns we built for the gun run event didn�t merely survive a couple hundred scouts over the week, they were in good enough condition that the camp kept them for future activities. Sadly that meant that I didn�t get to keep one, but I didn�t think I would anyways. Where do you find a water gun that can survive that kind abuse for under $40.00? You don�t, we built them from scratch using plumbing parts. Here is how:

Materials:

Plumbing Parts

1. 1x   ½" female barbed to ½" MIPS coupling
2. 1x   ½" FIPS to ½" female sol coupling
3. 2x   ½" sol x sol one way check valve
4. 1x   ½" female sol to 1" male sol adapter
5. 1x   ½" sol end cap
6. 3x   2" long piece of ½" white PVC pipe
7. 1x   14" long piece of ½" white PVC pipe
8. 1x   1" sol coupling
9. 1x   1" FIPS to female sol coupling
10. 1x   1" MIPS end plug
11. 1x   12" long piece of 1" white PVC pipe
12. PVC glue
13. PVC primer (purple)

Other Parts

14. 1x   4L milk jug with cap
15. 1x   5 feet of garden hose
16. 2x   10" long piece of Electrical tape
17. 1x   Teflon tape, also known as pipe tape (optional)
18. 2x   15/16"OD x 13/16"ID x 1/8" o-ring
19. Vaseline

Tools, etc.

20. Newspaper
21. Drill
22. 1/8" drill bit
23. 7/8" drill bit
24. Sandpaper
25. Sharp knife
26. Sharpie or other black permanent pen
27. Pot of boiling water

Preparation:

1. Drill a 1/8" hole into the tip of the ½" sol end cap (e). This will be the nozzle of the water gun when assembled.
2. Drill a 7/8" hole into the tip of the 1" MIPS end plug (j). The ½" pipe must slide into this hole, so enlarge it with sandpaper or the knife until the pipe slides smoothly, but don�t make the hole too big or the gun will lose its seal.
3. Cut two shallow grooves into the 14" long piece of ½" white PVC pipe (g) about 1 to 1½ inches from one end. Make the width just a little narrower than the o-rings. Make sure the grooves are absolutely no deeper than half the pipe wall thickness, or your pipe will snap inside the gun when you use it.
4. Mark the flow direction on both of the ½" sol x sol one way check valves (c) with a big black arrow (use sharpie). If you glue the valve in backwards, the whole gun is garbage. You can paint the gun or sandpaper off the mark once your done assembly.
5. Put one end of the garden hose (o) into the boiling water for about 15 seconds. Once it is almost too warm to touch, cram it (literally) over the barbed end of the ½" female barbed to ½" MIPS coupling (a). If you don�t get it all the way on before the hose cools, dunk the whole thing for a couple more seconds and cram some more.
6. Cut an X into the lid of the milk jug, big enough to let the hose fit through.
7. Lay out the newspaper over your work area, the glue and primer make a disaster of anything they touch.
8. Paint the PVC primer (m) on all the smooth ends of all the plumbing parts, inside the female ends, outside the male ends.

Assembly Instructions:

To glue two parts together, paint the glue on the end, do not glob it on, but use a good amount, you can wipe off the excess if your quick. Make sure you press the parts together very firmly and quickly, once the parts touch you have about 3 seconds before the glue sets.

You will be building the gun in two sections, steps 1 to 8 are the first section, 9 to 16 are the second. Unless the instructions say otherwise you will always be adding pieces to the existing parts you have already glued together.

Section 1:

1. Take the ½" FIPS to ½" female sol coupling (b) and glue it to one of the 2" long pieces of ½" white PVC pipe (f).
2. Glue the back end of one of the ½" sol x sol one way check valve (c) to the other end of the 2" long piece of ½" white PVC pipe (f) from step 1.
3. Glue the second 2" long piece of ½" white PVC pipe (f) to the front end of the ½" sol x sol one way check valve (c).
4. Glue the ½" female sol to 1" male sol adapter (d) to the other end of the 2" long piece of ½" white PVC pipe (f).
5. Glue the 1" sol coupling (h) to the ½" female sol to 1" male sol adapter (d).
6. Glue the 12" long piece of 1" white PVC pipe (k) to the 1" sol coupling (h).
7. Glue the 1" FIPS to female sol coupling (i) to the other end of the 12" long piece of 1" white PVC pipe (k). Put the assembly to the side to dry, you are done with it for now.

Section 2:

9. Take the 14" long piece of ½" white PVC pipe (g) that you cut grooves into earlier. Hold it by the end that has the grooves in it, make sure your hand is covering the grooves.
10. Glue the opposite end of the 14" long piece of ½" white PVC pipe (g) that you are holding to the back end of the other ½" sol x sol one way check valve (c).
11. Glue the last 2" long piece of ½" white PVC pipe (f) to the front end of the ½" sol x sol one way check valve (c).
12. Glue the ½" sol end cap that you drilled the hole into to the 2" long piece of ½" white PVC pipe (f). You can put down the section you are working on now.
13. You are done with the glue, clean up the rim of the can extremely well or you will never open that can again.
14. Slide the 1" MIPS end plug (j) onto the 14" long piece of ½" white PVC pipe (g) so that the threaded side is pointing towards your grooves and away from the check valve.
15. Wrap one piece of electrical tape (p) around the 14" long piece of ½" white PVC pipe (g) between your grooves and the 1" MIPS end plug (j). Make it about ¼" away from your grooves. The tape is your back up in case a o-ring unseats.
16. Put both the o-rings (r) around the 14" long piece of ½" white PVC pipe (g), seated in the grooves you made.
17. Wrap the other piece of electrical tape (p) around the 14" long piece of ½" white PVC pipe (g) between the groves and the end of the pipe Make it about ½" away from your grooves.

Final Assembly:

1. Coat the o-rings (r), electrical tape (p) and everything in that area with a very, very generous amount of Vaseline. Get messy!!!
2. Insert Section 2 into Section 1. It may take a bit of coaxing to get it in. If you absolutely can�t fit it in, cut your grooves a teensy weensy bit deeper and try again, and add more Vaseline.
3. Slide the parts together until you can screw the 1" MIPS end plug (j) into the 1" FIPS to female sol coupling (i). Screw them tight.
4. Screw the ½" female barbed to ½" MIPS coupling (a) into the ½" FIPS to ½" female sol coupling (b).
5. Let everything dry for a day before testing.

Done!

Now fill the milk jug with water, insert the hose and start to pump by sliding section 2 in and out. Once you have pumped out all the air you will be blasting water. A strong scout can shoot roughly 4L or water 25 to 30 feet in about 2 minutes!