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APH parts list

Written by Ben
Last updated on 2008-11-11

Prices are in USD as of December 2004. Where I bought each part is under the "Bought at" column. The parts can be bought elsewhere. If any parts are hard to find, try McMaster-Carr's online store. The total cost does not include sales tax.

Clicking on the part names that are links will display a photo of the part. Note that different brands are acceptable as well.

This particular water gun uses a backpack. An onboard reservoir is also possible, however I have made the choice for a backpack because they are cheaper and carry more water.

A checkbox has been added to assist when buying these parts.

# required Item Price per Total cost Bought at Checkbox
PVC pipe (all schedule 40), cement, and primer
5' of 3" PVC pipe $5.43 $5.43 Lowes
5' of 3/4" PVC pipe $1.32 $1.32 Lowes
5' of 1/2" PVC pipe $0.98 $0.98 Lowes
8 oz. of PVC purple primer $2.96 $2.96 Lowes
16 oz. of PVC cement $5.94 $5.94 Lowes
Check valves
2 1/2" PVC check valve (also called one-way valves and non-return valves) $5.85 $11.70 Lowes
1/2" elbow $0.16 $0.16 Lowes
2 1/2" female adapter (1/2" female threaded pipe to 1/2" female pipe) $0.24 $0.48 Lowes
1/2" x 3/4" male adapter (1/2" male threaded pipe to 3/4" female pipe) $0.20 $0.20 Lowes
1/2" endcap $0.18 $0.18 Lowes
1/2" tee $0.18 $0.18 Lowes
1/2" diameter wooden dowel, at least 15 inches long $1.73 (for 36 inches) $1.73 Lowes
10 #9 (5/8" OD) O-rings $1.27 $1.27 Lowes
Washers (about 3/4 inch OD) $0.49 $0.49 Home Depot
Vaseline $2.99 $2.99 CVS
Pressure chamber(s)
* marked items reflect the number of PCs you have (2 is the example) Number of PCs:
* 2 3" endcap $2.33 $4.66 Lowes
* 2 3" x 2" coupling / reducer $2.14 $4.28 Lowes
* 2 2" x 3/4" bushing / reducer $0.76 $1.52 Lowes
* 2 3/4" tee $0.27 $0.54 Lowes
Nozzle and firing valve
3/4" PVC ball valve $2.94 $2.94 Lowes
3/4" male adapter (3/4" male threaded pipe to 3/4" female pipe) $0.19 $0.19 Lowes
> 5 3/4" threaded endcap $0.79 $3.95 Lowes
Miscellaneous items
3/8" x 1/2" barb to MIP adapter $0.85 $0.85 Lowes
Teflon tape $1.98 $1.98 Lowes
Electrical Tape $1.39 $1.39 Lowes
Newspaper and a ventilated area free free Your home
Optional items (not included in the totals)
Carrying strap Wal*Mart
Rope (to attach the strap) Wal*Mart
Total $58.31
Total for second APH (given you will have extra parts leftover) $31.83

Prices will vary, especially considering that these prices are 3 years old. I would save $75 for a first APH. That is a fairly safe amount, and you will be happy if the prices rise because you can still create your gun.

Important notes about part substitutions

When large diameter PVC pipes are not available it's common to substitute other bottles. Never use glass bottles or any other bottle that is not designed to handle pressure. I can not make this clear enough. Most plastic soda-type bottles can handle a decent amount of pressure because they are designed to.

Also, when using a bottle, realize it is not as strong as PVC and should be treated gently. Do not use extremely high pressures especially.

Parts you will have spare of

  • 5' of 3" PVC
  • 5' of 3/4" PVC
  • 5' of 1/2" PVC
  • 8 oz. of PVC Purple Primer
  • 16 oz. of PVC Cement
  • 1/2 inch wood dowel
  • 10 O-rings
  • Vaseline
  • Washers
  • 260" of Teflon Tape
  • Electrical Tape

You will end up with several times more PVC than what you will have used in the construction of your water gun. This can be used for more water guns. PVC cement and primer will last for several water guns. O-rings, washers, and Teflon tape all should last nearly indefinitely, given that you don't build 10 water guns! You can see that the price for a second APH is about half the price for the first APH, simply due to the amount of extra parts you have to buy.

Tools and machinery required

  • hack saw
  • 3 1/2" clamp
  • drill press or hand drill (with many drill bits)
  • ruler
  • scissors
  • goggles
  • coarse sandpaper
  • file

Not every tool is completely required, but at the very least you should have a saw, a drill, and goggles.

All parts and tools together

I tried to show the relative scale of the parts by changing the size of the images in the parts list, but you may still not have a good idea of the size of the parts. The images below show most of the parts compared against each other. Note that I have an aluminum dowel here instead of a wooden dowel. They are about the same size and length.

Below are some of the tools I used. You can see my wide assortment of drill bits that allow me to make a large variety of nozzle sizes.

Next: APH construction

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