To Vac or Not to Vac

[erospawn]

(05-04-2010, 03:30 PM)bwayne64 Wrote: Thanks Jase, I was actually asking if pressure casting the mold would work like degassing. I've heard people have done this, but didn't know how well it works. I'll have a vacuum pump for a vac former, but was just curious if the pressure thing would work. It's not so much about money as it is about using the pressure pot for double duty, I hate unitaskers, Like Alton Brown the food network guy, LOL. Thanks for the reply,


PS. Hey I went to the Smooth On site and found this,

http://www.smooth-on.com/faq_display.php?faq_id=81

Joe

Not really.. it would actually make the problem worse.. When you mix the rubber, you're introducing tiny air bubbles as you know.. When you pressure cast, these air bubbles might pop under the pressure and resin seeping in. This results in these little pockets and rough areas on the surface.. You could sand them out, but you run the risk of losing your details too. If you don't want to use a Vaccume chamber, its possible to use Brush on rubber.. they do make that stuff and it works pretty well. I haven't done a lot casting, but I have used that stuff to make my parts and I haven't had any issues with air bubbles.

Heh, I didn't see the link to that FAQ when I posted the above