Eben, If your vac pump runs for 24 hours then you have a hole is your system! Really, once you pump down a system and your epoxy outgases a bit for air, the bagged system should not require any further vacuum. While the small pumps I use pull a small volume, once the vac tank is down, the system only starts when it responds to leaks. You do not need a fancy pressure switch, as a 1-2psi deadband works OK in normal switches. As for thinning epoxy, I have use some Isoproyl alcohol, 99.9%. Watch out for water!!!! It will cloud the epoxy. Chris Adams >A pump like that I wouldn't run 24hrs, but I'm sure if you add a non-return >valve (or cut-off of some sorts) and use a vacuum advance from a car to >activate a microswitch, which in turn drives a 555 oscilator in monostable >mode, to switch on the pump for say 20s when the vacuum drops, it should >work well. >regards >Eben > >-----Original Message----- >From: Aerofoam [mailto:[EMAIL PROTECTED]] >Sent: 16 October 1999 02:01 >To: [EMAIL PROTECTED] >Subject: Re: [RCSE] Vaccum Systems > > >I just saw an ad for a vacuum pump for $19.99 in the Harbor Freight >catalog. It's advertised as a pump to evacuate AC systems and dry them prior >to charging them with freon. >I am sure it is cheap Chinese MFG. like most of their stuff, but >I bet it would work fine for bagging. >They have a website and do mail orders. > > Mark Mech >[EMAIL PROTECTED] > www.aerofoam.com > > >RCSE-List facilities provided by Model Airplane News. Send "subscribe" and >"unsubscribe" requests to [EMAIL PROTECTED] >RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
