RE: need advise with Resin SG95 MCP

From: Gert van Rooyen (
Date: Wed Oct 23 2002 - 13:59:51 EEST

We use SG95 quite successfully for a lot of our parts.

It's difficult to comment accurately, because I obviously don't know how
you've made your silicone mould or how you're orientating the part during
your casting process.

Maybe just check the following:

Make sure your entry gate is at the lowest point and your exit is at the
highest. I would suggest having them diagonally across the cube, tilting the
mould during the casting. Thus forcing the air out of the mould gradually.
Make sure you have only one exit so that you minimize the possibility of
leaking air back into the mould.
Make sure your exit vent is high enough above your part, so that when you
leak air back into the vacuum chamber and the resin level drops, again it
does not suck air back into the mould.
Check the moisture in the air, if it's quite high, let the vacuum chamber
suck a little longer before you start stirring the B-component. I normally
do it after 3 minutes. Especially on a wet winter's day.
Cleaning solvents can also effect the resin, especially Acetone. Make sure
you clean the vacuum chamber only with alcohol.
Obviously the last reason can be the resin itself. Maybe it has reached the
end of it's shelf life.


Gert van Rooyen

Freeplay Technology
Montague Gardens
Cape Town
South Africa

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-----Original Message-----
From: Andrey Falaleev []
Sent: Tuesday, October 22, 2002 2:37 PM
Subject: need advise with Resin SG95 MCP

Hello List,
I need advise of vakuum castings experts. Help please.

We have many bubbles on the upper surface of part after vakuum casting
to silikon form.
material: Resin SG 95 MCP;
Part: Transparent cube 50*50*50 mm ;

Is anybody have this problem too? Is it usually for this type of
Thank you for attention.
Best regards,
Andrey Falaleev
BIBA, Bremer Institut für Betriebstechnik und angewandte
Arbeitswissenschafr an der Universität Bremen,
Hochschulring 20, D28359 Bremen

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