11-21-2009, 11:05 AM
(11-17-2009, 02:25 AM)erospawn Wrote: Hey Ed.. Thanks for that info that really helps! If the parts are really large, you could use the brush rubber right? Mold-Max 30 or 40 brush on version, atleast trom what I've read so far.. and you don't need to degass that do you?
Also, I've looked around, and the only vacuume chamber I could find was the one Smooth-on sells. What other brands are there for this?
Mold Max 30 is the way to go...The thickening agent ( Thi-Vex) that Smooth-On sells is ment for Mold Max 20 and 30....not ment for 40
You also might consider getting the fast catlyst with the Mold Max 30
You can really control the speed of cure with that stuff.
As for de-gassing...no, you really don't need to if you're troweling the silicone. But, your first coat or two should have no Thi-Vex in the mix...
You want a thin, runny mix so the silicone will capture all the details.
( this is where the fast catlyst comes in handy...you can speed the cure so the silicole doesn't run off the master so badly )
Once you have these "skin" layers down and cured...then you can start building up to a 3/8" thick layer....the thick silicone will fill in pockets and undercuts real well also.
As for vacume chambers...I'm not that well versed on what's out there....I bought mine when I first started....it was one of my major investments ( $1,000.00 ). My chamber is large enough to hold a 5 gallon bucket. ( I don't mess around ;-)
You may want to look into jewelry supply houses...look for the bell jar type...not so expensive...smaller, but still functional.