How fast/slow does your vacuum setup loose pressure?

[pmg]

Hi,

as the power breakdown yesterday might have trashed my build, I was wondering how fast vacuum presses of other builders loose pressure.

My press takes about 15-20 minutes to completely loose pressure (well, perhaps not completely, but not enough to press a ski). The pump is a Thomas 2650, and I get about 870 mBar pressure.

Cheers

[chrislandy]

With my vac line disconnected (using a quick connect fitting) and a sealed bag it doesn't loose vacuum at all (I've done a 2 day cure before when I didn't have an oven up and running). If it looses vacuum then there's a leak somewhere

[pmg]

Hmm, carefully checked for leaks, didnt find any. could it be that some air gets back in from the pump when its switched off?

[chrislandy]

You should clamp the line or use a vacuum suitable quick connect like these:


on the odd occasion I've turned the pump off and forgotten to disconnect or clamp the line it's sucked the oil straight out of the pump and up the hose! If you're using a dry pump then it's likely there is no non return valve so that may be the reason it looses vacuum so quickly

[mammuth]

Like written in your thread, use a check valve between pump and vaac tank. Look for one where the spring is not too strong, dont know how it works with vaac & too strong spring. Mine i got with the venturi from veneer supplies.

Just test your system without a bag, then you see if the system is good.

[OAC]

Are you using the "Joe wood worker set up" with a vacuum reservoir? Skip it and run the pump continuously, then you don't have to bother about tiny leaks.

[mammuth]

This doesnt help him with power failures

[pmg]

Had an easy test today: My manometer is attached to the pump, so I clamped the vacuum hose close to the pump. Lost all of the vacuum in less than a minute, so its the pump that "leaks" when switched off.

[mammuth]

Buy a Rückschlagventil at the next plumber/baumarkt and you should see a big improvement. Just a few euros this part.