Selecting a Vacuum Pump

[TheMasterTurtle]

I'm going through the process of finally doing this the right way. I've never used a Vacuum Chamber so I've been doing extensive research into doing things well.

I've found a second hand Yellow Jacket 8cfm 2 state Vacuum Pump for $175. The seller says it works. What questions exactly should I be asking or what should I be looking for to know that this functions properly, is a good buy and will work for me. Im also planning on a custom chamber build so I have to figure out the appropriate pot size for that as well.

here's a photo:


I should add that this is out of state for me and I would need a friend to pick it up for me. I can't do anything first hand.

[mangozac]

I guess you could get him to take a photo of it connected to a gauge and pulling a good vacuum? Other than that there's not a lot you can do...

[TheMasterTurtle]

Thanks I pretty much thought that would be the case. looks like the pump sold anyway. Should I hold out for a Yellow Jacket? I found a robinair but have read mixed reviews on those. Thoughts?

I happened to stop by Big Lots and they had a sale yesterday. Any thoughts on using this as my pot for the chamber? It's a TeFal 8qt Aluminum stockpot. They had some stainless steel ones there as well but all had give when I put them on their sides and put weight on them while this didn't. I just wasn't sure how an aluminum pit would hold up.

[mangozac]

Honestly I'm just using a cheap ebay pump which I'm sure doesn't perform spectacularly. We don't need scientific levels of vacuum!

My pressure only chamber is made from an aluminium pressure cooker which I estimate is about 2-3mm thick. Without knowing a bit more metallurgy I'd be hesitant to use a non-pressure cooker pot as it's not at all designed to handle any pressure stress.

[TheMasterTurtle]

I appreciate the input. I keep reading and reading but it's hard to sift through what I find because there's not many wrong answers to my questions, just preferences.

I had the same concern about the pot. I did coincidentally also find a pressure cooker at goodwill for 15 bucks. It's about 6" deep with a 11 inch diameter. That would do fine for me but I hoped for something that was taller and maybe a 9-10" diameter. I may just make it work. I ordered all my valves and such. Just need it all to come, drill my polycarbonate, attach fixtures and oh yeah... Choose/ purchase the vacuum pump!

Thanks for the feedback.

[mangozac]

[TheMasterTurtle]

So I'm still on the hunt for a good prices Vac Pump and this recently popped up. I don't know the brand but it's new in box for $135. What I'm curious about is the "stage." All The pumps I've looked at have been 2 stage while this is 1 stage. How important is that?

[Fleafa]

I have always been under the impression you want a two-stage pump. It has been a while since I discovered the reason for that...