Over pressurising a floor pump.

[Mitchza89]

Yet another post from Mitch haha. There is a Silca pump on ebay for 20 bucks. It's maximum psi level is 220psi, but I'm looking to get 300. If I was to go over the recommended psi level, would I break the pump?

[paaiyan]

I bet it can actually handle more than what it's rated for, though there's no way to tell how much more exactly. I wouldn't recommend going 80 PSI over though.

[Mitchza89]

Yeah thats what I thought...Blegh I hate spudding sometimes...There are just too many options!

[jackssmirkingrevenge]

They look quite heavy duty, I think you'd have to try pretty hard to break it - and even if you do, unless it's a catastrophic failure it should be easy to repair.

The major problem would probably be screwing up the gauge.

[paaiyan]

I know you can probably get a good shock pump from a sporting goods or bike store. Look around for those, they usually aren't too much.

EDIT: Found one on some bike store's site. 30 bucks and it's rated for 300.

[Mitchza89]

Thats the problem. I'm making a very large gun pretty soon so I need a decent size pump. With a shocky, my arms are gonna be stuffed

[jackssmirkingrevenge]

I know you can probably get a good shock pump

The problem with shock pumps is that they offer good pressure but low volume, meaning that if your chamber is bigger than a few cubic inches you're going to go through a lot of blasphemy to take it past 200 psi.

[Mitchza89]

Yes! What Jack said!

[cwazy1]

make one dude i saw ur other thread but making a oring piston for the pumping isnt that hard. i was scared to do it at first but once i figured out that you can really trust orings and easily make grooves for them w/o any equip, i was jum,ping all over this

[shud_b_rite]

I over pressurized a 160psi floor pump once and it broke the check valve inside it and now it only acts as a pneumatic ram.

[jackssmirkingrevenge]

I over pressurized a 160psi floor pump once and it broke the check valve inside it and now it only acts as a pneumatic ram.

If the attachment doesn't physically open the schrader it can still be used, how does it attach to the valve?

[shud_b_rite]

Dont know what its called but its one where you push it onto the shrader and push the little handle 90 degrees so that it stays on. How do you mean it can still be used? I would have to install a check valve or some manually operated valve somewhere on the hose. Or to disconnect the shrader from the pump after every down stroke.

[jackssmirkingrevenge]

when you push down the handle, it pushes a little pin inside that pushes the schrader stem open. If you can cut off that pin you should be able to use it normally, as air will enter the schrader through the pressure difference and it will effectively act as a check valve.

[shud_b_rite]

Ahh your right it does have a little pin inside it. I'll try it sometime. Thanks

[Hotwired]

All pumps can take overpressure, you're not going to get a guarantee from anyone about it though.

My pumps gauge reads to 160 and I overpressurise it to 240. At which point it touches the 0psi pin from the other side

It works fine but the gauge doesn't read 0 at 0psig anymore, stops at the 5psi mark.

Not surprising as the needle goes well past the 75% of gauge maximum pressure you're meant to use gauges at to make sure they stay accurate.