Specs for a Vacuum Chamber and Pressure Chamber

[cavx]

WOW it has almost a year since I have done anything on this.


Anyway, the Vac Chamber is complete and works!





I still can't pull a full vacuum (29.5" of mercury) as it seems 28.5" is all this little pump will do. The latest upgrade done today was to mod the top so the huge O Ring can just sit on top and be squashed down and add a ball valve inline between the chamber and the pump. I did this because once the pump is shut down, the vacuum in the chamber sucked the oil out of the pump.

 

[crazygrandma]

I agree, I purchased mine from Harbor Freight except I got the 3CFM 2 stage Vacuum pump and the same pressure tank. Its worked great for degassing silicone and resin. I have the system pretty much daily for a couple years. Its the one tool I don't mind spending the money on. Silicone is expensive, the unit has more than paid for itself.

 

[cavx]

Sorry if my question seems dumb, what is a 2 stage pump?

 

[lurch]

the second stage helps in achieving a lower ultimate pressure.

The belt drive vacuum pump I have is a 2 stage.. similar to this one:
https://www.sargentwelch.com/store/catalog/product.jsp?catalog_number=WL1400B-01

but other companies like Varian (now called Agilent) make direct drive 2 stage vacuum pumps like these:
Pompe per vuoto - P.V.R. Progetta e produce pompe e sistemi per vuoto
Holly molly thats a messed up address. google Agilent instead I wouldn't even click on that link jeesh...

these are way more expensive and totally worth it if you need that little teeny tiny bit more.

Kevin

 

[cavx]

Thanks for that Kevin. I little pump I bought cost me a whole $103 off eBay and I think that even included the shipping from Sydney. It will do to get this up and running and in time I can look at a serious upgrade. There is a pump supplier in the next suburb that has larger industrial pumps starting from about $1100.

So far this Vac Chamber has cost me just over $400.00, so not a huge outlay. The chamber itself has cost me $130. The hoses and hardware have been the most expensive parts at about $170 and the pump makes up the balance.

 

[Fireball Joe]

Just for reference, here are some photos of my Vacuum Chamber:

The upper gasket is made from Mold Max 30 that had gotten too thick to use for a mold. The top & bottom plates are 1/2" Lexan and the body is made from a piece of 10" water main pipe and it is attached to the bottom plate with silicone caulk. Pump is from Harbor Freight, as is the nifty brass 4-way that lets me mount a gauge and a relief ball valve. For the hose connections at the pump & chamber, I used brass barbs and clamps because generic quick-connects can be leak under high vacuums. This rig was cheap-- under $200 for everything-- and since we live virtually right at sea level now, it pulls to just under the 30" mark on the gauge. Where we used to live, it pulled around 29" to 29.5" depending on the weather.

 

[cavx]

WOW I didn't take temperature or altitude into consideration. I don't think I am that far above see level.