SpudFiles

Alright, I'm thinking seriously about buying the washer gun at the top of this page. It says 12 gpm, but I have no idea what kind of flow that amounts to. How does 12 gpm compare to, say, a husky blowgun. I hope to pilot 1 inch piston with this.

12 gallons per minute

^^^I know that, but It means nothing to me. I'm asking for a comparison to an npt hole or a blowgun or something. thanks anyway

12 gallons per minute is 12 gallons per minute, i don't know what else you want i mean if you want you could break it down or change it to metric, i don't know what you want

Nooooooooo, don't do it! I pulled one of those apart 3 days ago and found that it was totally unsuitable for a spudgun. The ball and seat would restrict flow A LOT. Unless you plan on using insane pressures it is a no-go. See if you can find a cross sectional diagram of one and you will understand what i mean.

Edit: 12gpm is around 60 litres per minute (f@#k all).

You dont happen to have any pics of the internals, do you? Its basicly just a high flow blowgun right? EDIT: It doesn't need to have enough flow to be the main valve, this is just a pilot. so anything over 1/4 would be great for me.

Nope, it is designed for high pressure liquids. The inside of the "barrel" was 10mm, leading to the nozzle, about 2mm dia. The ball lifts off the seat only about 2mm (which according to JSR's D4 rule should be fine) but in this application i just cant see it working. Remember that it is designed for LIQUIDS not air. You would probably have problems with it leaking.

I may be wrong and most probably am, so you best wait for other replies

Edit: A pilot you say, why not use a normal blowgun? What pressures do you plan on using?

I cant use a blowgun because my design has about 5 inches of unavoidable hose and that makes for too much pilot volume. (sorry jsr) I heard that these wash guns had way more flow than blowguns, so i thought i would ask.

Remember that is gallons of water. It would be different than gallons of air due to the characteristics of each medium.

mopherman wrote:I cant use a blowgun because my design has about 5 inches of unavoidable hose and that makes for too much pilot volume. (sorry jsr) I heard that these wash guns had way more flow than blowguns, so i thought i would ask.

Meh. Too much is put on the value of pilot volume.

If I'd told myself 30cm of 8mm copper tubing was too much to pilot a 1/2" QEV with a blowgun, I'd never have made the cannon in my sig.

That would have lead to a fair few other cannons not being made.

Hotwired wrote:

mopherman wrote:I cant use a blowgun because my design has about 5 inches of unavoidable hose and that makes for too much pilot volume. (sorry jsr) I heard that these wash guns had way more flow than blowguns, so i thought i would ask.

Meh. Too much is put on the value of pilot volume.

If I'd told myself 30cm of 8mm copper tubing was too much to pilot a 1/2" QEV with a blowgun, I'd never have made the cannon in my sig.

That would have lead to a fair few other cannons not being made.

true, but you can pilot a 1/2 qev with pretty much anything. This is a 1" piston were talking about. If this doesn't work out, I'll just make a 1/4 porting piston valve for a pilot.

A blow gun should have no problem piloting a 1" piston valve. A 1/4" hole pilots a 2" piston valve no problem. As for the 12gpm, thats like running your kitchen sink for a minute. Ben is correct about water and air being different, totaly different flows between the two. If you get a standerd blow gun like Nova says, you can find modding instructions in the wiki and make it even better. A modded blow gun should work fine for you.

jrrdw wrote:A blow gun should have no problem piloting a 1" piston valve. A 1/4" hole pilots a 2" piston valve no problem. As for the 12gpm, thats like running your kitchen sink for a minute. Ben is correct about water and air being different, totaly different flows between the two. If you get a standerd blow gun like Nova says, you can find modding instructions in the wiki and make it even better. A modded blow gun should work fine for you.

I agree about water and air being totally different mediums, but you also have to remember that 12GPM is achieved through this gun when powered by a pump producing around 3500psi- flow will be reduced dramatically if used at pressures around 100psi (normal spudgun pressure).

Anyone want to do the math?

Uh oh...
I bought a pressure washer handle for the pilot on my high pressure BB gun. And it only gets 10gpm maximum flow (@4000 psi w/ water) Of course, I'll have less than 0.25ci of pilot volume. Assuming 2400 psi helium, can someone do the math and tell me if I just wasted $40? I know helium flows faster than water or air. [/hijacking]

If a blowgun can take the pressure, just use it instead. Far cheaper, and possibly better flow.

I can't see your pressure gun being a problem at 2400psi, that is if it doesn't leak like a sieve.