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Last updated on 2007-12-18

Can I substitute a schrader valve for the pump on the APH?

No, the pump actually moves the water into the pressure chambers; without it the gun can't work. A schrader valve can be used to add extra pressure to the chambers though.

Can the APH be built with the chamber inline with the nozzle?

No, the chambers must be upright or at least angled. The air needs to push the water out, and since air rises, it must be on the the top. An inline design would release some water and all the air because the water is not below the air.

How can I achieve a certain pressure in a certain number of pumps in an APH?

Consult the APH design tool to help design to your own specifications.

How does the water get into the chambers of the APH?

The pump moves the water into the pressure chambers, pressuring the gun simultaneously.

How much does an APH cost?

The cost varies but for the most part, a first APH can cost as little as 30 USD or as much as 100 USD, depending on the availability of tools and parts. Subsequent guns will cost much less though because not all of the materials for the first gun are used.

How much does an APH weigh?

Ben's single-chamber APH weighs 2 pounds (.9 kg), and his dual-chamber one weighs 4 pounds (1.8 kg) when both were empty.

Should my gun have four pressure chambers and ball valves between each chamber so that I can control how much water can be used a once?

This has been tried before with limited success. The dividing ball valves were designed make a multi-shot APH, but the performance suffered overall.

What is the backpack needed for in the APH article?

The backpack is were the water comes from. It can be substituted for an onboard reservoir though.

What is the maximum number of pumps an APH can take?

Again, this depends on the gun and how it was built. Consult the APH design tool to help design to your own specifications.

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