-
Stop messing about - just get a Sub-driver! -
Very interesting.
I have pressurizing equipment (compressor and a converted pressure cooker), but don't have a bell jar for degassing, and boy are those a price, if you can find some place that sells them over here!
For thin section, how about putting a few risers in at the sharp points, so any trapped air can escape and be squished out under pressure?
It means more clean up work, but that's no sweat for me, as I'm only making a few parts.
Another thing I thought of trying was to place the mould on a vibro plate (I have an old vibro saw which will work), and let that jiggle the air out, assuming the use of a slow cure PU resin. -
All viable means of catching the bubbles or chasing them out.
Oh, and finish that damn Beatles sub tooling ... I want one!
David,Who is John Galt?Comment
-
If you have one of those Black 'n Decker Mouse Sanders, shove it in a vice upside down and just place the container with the freshly mixed resin onto the rubber pad. A few seconds of that will shake the living daylights out of those bubbles, fast enough for even a quick-set resin.
Stop messing about - just get a Sub-driver!Comment
-
Ha, ha! Attack of the blue meaniesComment
-
Oh, man ... you know way too much about that cartoon, Andy!
David,Who is John Galt?Comment
-
Well I have the DVD, but I only got it for reference to fill in the missing pieces with the AMT/ERTL model.
Never understood what all the fuss was about to be honest, think you had to be on something to fully apprciate it.
I prefer the kinks anyway.........Comment
-
Dave I saw the video on casting resin and you said for a min of 29 hg for the vac chamber. with my new set-up
in the pic here i can only get 21.5 hg@5280ft alt. why 29hg? I have talked to other cast resin companys and they insist on 29hg!
Thanks TomComment
-
Your little diaphragm pump does not have the ass to pull the higher differential pressure (vacuum) needed to degass the mix. Subjecting any liquid goo to anything less than a near hard-vacuum won't separate out the gas from the mix -- that gas mostly air entrapped in the goo as a consequence of the mixing process, more extreme in situations were you are mixing a very viscus material such as RTV rubber and its catalyst.
You either pull 29" of Mercury or you're wasting your time. Good looking set-up you have there, but the pump ain't gonna get it done for you.
David,Who is John Galt?Comment
-
I have already degassed some rtv (oomoo rtv from smooth-on) and it worked great! no bubbles at all! I thought i could get away with compensating for altitude out here. no worrys the pump was a free-be. the perks of being a driver for UPS:) anyway the problem i am having
with air is the cast resin. Ted and i have tryed alumalite but the stuff solidifies so fast we couldent work with it. I would be willing to give it another try though..Comment
-
Careful, there are two formulas of the ALUMILITE polyurethane casting resin -- on fast cure (about a 30 second pot life) and a slower cure. The slow cure is what I use for production work.
David,Who is John Galt?Comment
-
Dave, What kind of time are we talking about on the slow cure? TedComment
-
Alumalite's web site says
alumalite regular 90 sec pot life
alumalite white 2.5min
alumalite RC 3 3min
which one do you use DaveComment
Tweet
Comment