SpudFiles

I want to build a little hand pump for my bbmg for airsoft games. I think 120 psi would be pretty easy to achieve. I am wondering what diameter pipe would be best to use. I want to use a galvanized steel nipple for the main body, either .5 or .75 so it is easy to pump... I am wondering if I could go any bigger than that and still be able to reach the pressure I want, and possibly a bit higher...

galvanized pipe would not work well as a body unless you sand down the ridge on the inside. I would use a sch80 nipple, or find some threaded seamless pipe

Haha yeah I know I was reading the thread about the other dude's pump, but actually a sch 80 pipe nipple isn't a bad idea, at all.... would that be capable of holding 200 psi and what size would be the biggest I can use while still being able to pump it quickly and easily?

i would use 1inch pvc, ill have to check the math but it should be easy to get to those pressures in the pvc

Problem with using plain pvc is it's unthreaded, and it would make the piston unservicable, although I could use female adapters to make it able to be opened, I'll think about it... cool thanks.

and if you go with something as large as 1 1/4 pvc you could epoxy a 3/4inch fitting into the end for looks and reducing dead space. but 1 1/4 might not give you a high enough pressure that your looking for

3/4" copper pipe should do the trick, its smooth on the inside and should be easy to make a pump out of. You could put threaded adapters on the ends to make it serviceable.

3/4 or 1inch pvc is just as smooth and as easy to put adaptors on, also its cheaper and lighter

Yep agree with c11man, don't wanna use copper, it's overkill for the max pressure I'm using anyway, plus 1" pvc is rated to I think 450 psi so I'm fine... and it's easier to work with... and yeah 1 1/4 inch is a little too big I think for a hand pump, it would get a little hard to pump.

Just a note, brass nipples are smooth all the way...

brass nipples are smooth all the way

Haha I love taking things out of context...

And that's another option... pretty good one too, brass looks awsome and it is rated high enough for this purpose, but brass is expensive... Damn, I'm starting to talk like you with all the dot-dot-dot's lmao, I think I should put my title as DeathbyPW haha

1" may be pushing it a little for a hand pump. take the pump you have now, hold it to your shoulder and pump it up to its maximum pressure. if you have a normal bike pump this should be pretty hard, and your cylinder should be around 1". so I think you should go for a 3/4" sch80 nipple as the body instead of 1" sch40

Lockednloaded wrote:1" may be pushing it a little for a hand pump.

It most definitely is, for every 10 psi you have to push down with a force of almost 8 lbs, reaching 120 psi means you need to apply 94 lbs, practically you'd have to sit on it

I personally would go for copper, its pretty cheap, can do high pressure, is smooth. But the thing I like most about it is that you can solder some fittings too it without a bunch of excess reducers and stuff.

The only issue I see is that it may be eaisier to dent than pvc, but i think it looks much nicer.

Have considered a regged HPA/CO₂ setup? It's not too expensive (and a one time investment anyway), even cheaper if you set up a fridge compressor, and it will save you having to pump under fire