Hi! Total noob. Have a few questions about vacuuming/pressure pot?

[CasterTroy]

Hi, first of all I have to say I am so glad I found this forum. I have been conducting numerous searched on the internet about molding and casting and this seems to be one of the best so far.

I started casting resin parts and have come across the unfortunate part of bubbles getting caught up in the casting while the resin is curing.

I understand now that in order to get the clearest castings possible I should get a vacuum pump to degas the mixture before pouring, and a pressure pot in order to force out or compress any bubbles that can form during curing. I have a couple of questions that I would like to ask those who know a lot more than I do, and again, please forgive me if these answers are posted elsewhere, but I am still learning the lingo.

1. For a vacuum pump I am considering a Robinair, since they seem to be highly regarded around here. I am also looking at a few others as well. Is there such a thing as a combination vacuum pump/compressor to just get one unit for both functions?

2. I have an Iwata Power Jet compressor that, at least on paper, should be able to go up to 70 PSI, but not very sure if it would be up to the task for for the for a pressure pot. I was already looking at this compressor or something similar if I can't use my airbrush compressor.

3. There is a Harbor Freight where I live but they do not have any paint pots in stock and don't know when they will get any. I found this one on Amazon which looks identical. With shipping it comes out to about the same price as the one HF sells.

4. Last thing is I have read how some members mention using their pressure pot as a vacuum chamber. I would like to know how this is done. Not asking to hold my hand, but point me where to look. I did find a couple of posts where members gave links to the 405 site where some of their members explained this, but the posts are gone. If google is the way to go I will do that.

I really apologize if I am asking a lot. I know many members hate it when newbies start asking questions without doing any research. I just need to get some of these questions answered so then can help myself.

 

[robn1]

Hello, and welcome. The 405 thread is still there, took me about an hour to find it. They must have moved the thread around, breaking the link. The thread starts here, casting posts start here.

I picked up the HF paint pot and venturi pump last year, but I haven't put them to use yet, so I can't comment on their effectiveness. But the results in the 405 thread certainly look good. Good luck!

 

[JFB64]

Hi and first welcome to the sit and second you don't need to vacuum degas your RTV, if you use the right material. I know some members might disagree but I've never had a problem with mold distortion. I do strongly recommend using a pressure pot for both pouring rubber and resin however. I use to be a professional model maker and made a lot of urethane parts from RTV molds and I have a casting area set up in basement. I've been pouring at home for years and have developed a system that virtually guarantees a perfect part every time. If your interested send me a pm and I'll be glad to send you lots of step by step photos.

Joe

 

[CasterTroy]

Thanks for the thread links robn1.

I found a site where a member gives step by step instructions on how to convert a paint pot for pressure and vacuum. Think I would rather do the vacuum chamber on the cheap like Rube did on the 405.

Thanks for your input JFB64. I read for other souces as well that using pressure for molding and casting works pretty well for getting good results.

 

[thejeremyevans]

we've also had success with a vibrating table using a modified elctric sander. if you're using fillite with your resin mix. this'll really help you in your moulding and eliminate those nasty air bubbles