International Association of Penturners - View Single Post - Casting in a Vacuum
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Old 11-13-2017, 02:37 AM   #1 (permalink)
Houtkop
 
Join Date: Jan 2016
Location: Jhb, South Afrika
Posts: 55
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Default Casting in a Vacuum

Has anybody tried casting in a vacuum?

I have recently been given some mini pine cones and banksia integrifolia pods to try casting. I have had varying degrees of success using a slow curing resin and a 60psi paint pot. But due to the structure of the organic materials and viscosity of the resin, I find that I still end up with little holes close to the core of the material. (I use PVC pipe as a mold)

One of the solutions that I have thought of making a vacuum chamber with a vacuum port and a nozzle with a ball valve and reservoir. I would place my chamber over my mold with the nozzle pointing down into it, ball valve closed and resin in my reservoir before creating my vacuum. The next step would be to open the ball valve and filling the mold with resin. In theory, as the material is under a vacuum, the resin should penetrate into every hole, leaving no voids.

Things that I wonder about is:

1.) Would the cohesion of the resin and gravity should be sufficient to allow the resin to flow into the mold without it 'exploding' in the chamber.
2.) The rate that the vacuum will suck the resin into the chamber. It might be to fast for me to be able to stop the flow once the mold has been filled.

Any thoughts?
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