Is there a vacuum pump I can get that is less than $250 and can safely pull just 7 to 20hg.
My pump doesn’t like pulling low (?) vacuum levels for extended periods of time. I can run it at 5-15hg for just an hour or so, it spews oil out the exhaust and overheats if i keep it that low too long.
Anyone using a refridgerator or drinking fountain electric pump? What do you do about keeping those pumps oiled?
If you dont have a vac switch set up of some sort to switch pump off when certain vac level is achieved, and need to run pump continously for several hours, then its perhaps better to look for used quality professional type equipment, than cheaper new stuff.
I bought this pump from Ebay a couple of years ago: http://www.rtpumps.co.uk/rtpumps/central/products/resource.nsf/imgref/Download_807-1007-1107CK-CHI_WOB-L__3302_2-07.pdf/$FILE/807-1007-1107CK-CHI_WOB-L__3302_2-07.pdf
Cost £50 and had very little use from new, bought from a company that had been using the pump for laminating.
Alternatively anyone who has a shop compressor, might want to look at multi stage PIAB venturi pumps, which are inexpensive, and work extremely well.
Fastrr, go by that surplus store I told about you that is in your town! Just know what things go for and offer them low…
Hey Werks, i’ll go… send me the name of the company and address if ya got it. 
Thought you had a Robinair Fastrr? I just bought the vac switch & Mac valve from joewoodworker.com to add to mine so it’ll cycle itself. I’ll post pics of the setup as I put it together. Cost of all the parts was <50 bucks.
Mac valve - what is that?
Yeah i’d like to know how to set up my pump so it can cycle on and off as needed. I did find a couple problems why the pump may have been getting hot … i have a gas ball valve on my vacuum line that i was keeping partially open to maintain 7-10 hg. Some may say that’s not a good thing to do, but screw it I had no choice with this plug design. The other reason it was getting hot, i think, is because i had a couple air leaks, one at the vac line fitting, and a couple more in the bag itself. I need to get one of those hearing helpers so i can pin point bag leaks more easily. Someone here mentioned what i should buy for that, but for the life of me I don’t remember what it’s called.
why are you try to produce 7-20 hg’s? its called a ultra-sonic tester
A MAC valve is nothing more than an solenoid valve. The Mac valve is a gateway for vacuum pressure. It directs air flow to either the main reservoirs when additional vacuum pressure is needed or to an exhaust port when the system cycles off. This exhaust is simply a removal of pressure from the pump so that it can easily restart on the next cycle.
I picked this up from the Joewoodworker site where they supply the plans and parts to build a veneer press (just a big vacuum bag for laminating veneer woods/metals. My brother is a cabinet maker so we built one for his shop.
Here’s the full article.
http://www.joewoodworker.com/veneering/EVS/concept.htm
There are a few variations depending on which type of vacuum source you use pump or venturi generator. I have both.
Thanks Knotty:cool: I’ll look for the solenoid valve at the surplus store, maybe they have one there.
Is that all that is needed in order to have the valve work to control the vacuum?
how much did that end up running you?