Greetings,
I am getting ready to start casting some designs (mostly silver, some 14y & w) and wanted to see if there is anyone out there that has any knowledge / tips that I should be aware of. I have the Blue Castable material and am also curious if there is anyone out there that has tried the Purple Castable?
For now, all castings will be vacuum cast. As far as prepping the models prior to investing, I have heard that people spray their models with “Pam Original Cooking Spay”, in order to eliminate bad surface / trapped resin-build material in the investment mold. I should say this Pam thing was done with the Envisiontec EC3000 (green) material; to which I personally know of two different people, same machine model ( Micro+), and no successful castings!!!
Any help would be greatly appreciated and thank you in advance,
Erick
The most important insight into molding and casting is to understand that you are not pouring molten metal into an empty mold. you are pouring it into a mold that is already filled, with air.
You have to allow the air to escape, for the metal to flow in.
the porosity of the shell or investment is sufficient to allow the cooling metals to outgass thru the investment wall… however, its not quite porous enough to allow the air to get out as fast as the metal flows in…
and the minute the metal hits the cavity walls its starts to chill ans thicken.
so try and imagine the shape you are casting as if it were a thin walled blown glass bottle… and you need to have ALL the water in it drain completely away…
add gates and vents as needed to allow the imagined water to drain fully…
Yeah, I have been casting since the late 80’s, platinum as well (old school vertical centrifuge, since 2000ish).
I was just wondering if there was anything someone has encountered that is characteristically specific to this blue castable material. So, maybe special gates or specific placement of the gates? Maybe any deviation from the official “Castable_Usage_Guide.pdf”…?
…I guess, experimental techniques, due to any problems that may have occurred?
Thank you for responding!!!_________I had actually gotten into a bad habit of not implementing gates and must get back to doing so.
other than that- the thing about printed patterns is that they will expand before they burn.
this can crack investments, and is part of the reason for the weird graduated burnout schedule.
to that end, try to make your patterns hollow as best you can… even if you have to plug a hole or two with wax… this can help reduce the expansion stress on the investment by allowing the pattern to expand internally, and reducing the overall mass of resin to expand.