Castin Craft Polyester Resin - Plaster Mould

[badboi]

Hi,

A few quick questions which I havent found answers to on this forum

I have made several molds in Plaster.  I have three items to use as a release, Vaseline, Castin Craft mold release/conditioner, Artisitic Wax Medium.  I will be pouring Castin Craft Polyester Resin into the Mould (they are intended to be very solid (no bubbles) Prisms)

I have done a tester, and can Already tell there will be many air bubbles, how can I get rid of these in the "final pour"
Also, which combo of the above "releases" would work best.  Also, I have "plugged some air pockets with Plastecine, will this work?

Also the size of these prisms are about the size of an ice cube. 

I have been using the ratio of 1 ounce = 5 drops of catalyst... does this sound right?

and one more thing, how long will it take to set fully, so I can start sanding them?

thanks for the help.

[John C]

Your mix of resin/cat should be fine. For plaster molds I would use the wax mixed with kerosene, mix it so it does not cover the mold detail.

I have an old presser cooker that has been converted to a vaccuem chamber,, my pump is an old refrigerator pump.

I use this to pull the air bubbles out of the resin or the molding compound.

You can make a vac. chamber using a piece of 12 inch high pressure pvc pipe, the same pump.

cut the pipe to the length you need 12 inchs or so, them glue a piece of 1/4 plexiglass to the bottom, use the stuff for the hardware store, slow setting is better as this will make a better seal. Now repeat, but glue another plexi piece on the bottom of the bottom,  this will allow for super strength.

Once this is done, laminate two pieces of plexi for the top, run a small bead of a good grade of silicone around the top of the pipe this is your seal, make sure you do this and use minieral spirits to  work the silicone smooth and even.

I use the frig motor, with a solid  flexible copper tubing, yes you can get bendable tubing. I then soldier a male npt male coupleing to it.

On the lid for the chamber, I drill tap, and epoxy the female npt fitting.

You coould also add a vaccuem gauge in the copper line.

When you place anything in the vac. chamber be aware the product is going to rise or swell if you have it correctly running. So use a larger cup than normal for the product.