pressure vs vacuum

[joe966]

Any thought on which method works better for Allumilite? I have been casting in PR for a while now and rēcently decided to go to Allumilite.

I have a system that can do both pressure and vacuum but i have been having issues getting vacuum to work right with Allumilite. Seems to explode under a vacuum.

 

[lorbay]

Pressure. You can use vacuum for degassing, but you need to be able to see what you are degassing, like a thick acrylic lid.
Lin

 

[TimS124]

Pressure.

 

[VE5MDH]

To add to Lin's comment, I've seen 1"x12"x12" (costly, it is said) clear acrylic used with success. I've also seen thinner one's fail (crack, shatter & destroy the project), not personally though, as I'm just scooping up (as much information (and pieces/items)) as I can while I'm on my vacation.

Michael

 

[resinman]

Vacum removes the bubbles. Pressure comporesses them.

 

[Ed McDonnell]

I suppose that vacuum could be useful for degassing the individual parts of Alumilite before you mix them. This might allow more bubbles to be dissolved into the resin under pressure (rather than just shrunk down to a smaller size). I wonder what else might vaporize out of the unmixed alumilite components that might affect things?

In my experience, once I got the two parts completely mixed and everything in the molds, I didn't have a lot of time left to get things under pressure. I am pretty sure I would not have had enough time to try and vacuum the mixed resin and then get it under pressure.

But, that's just me. Maybe I'm slow.


Ed