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Lost? All roads lead to Plaster Master
Work at Home pg 6 Plaster Master guide to home business
A Level Headed Mold Will Stand on it's Own
Remove the Clay When the first section has hardened
turn it around and remove the clay from the back of the plaster shell. Making the Second Half Making the second half of the mold shell is much easier. Shellac and soap the mold shell
Apply a coat of shellac to the mold
shell half you just made. Then soap up the plaster shell with mold soap. Give it two
coats, let it dry. Apply plaster soaked strips the same as the first half
Mix up a batch of plaster and put a
heavy coat of slurry on the soaped up mold half then apply plaster soaked strips the same
as you did on the firtst side. This is the finished mold
We haven't opened the plaster jacket
yet but this is how it looks with the rubber mold still inside.
You can now drill 1/4 inch holes in the edge of the back up shell for the clamping bolts that will hold the two halves together. Be careful not to drill through the rubber mold.
Dynamite or a Gentle Tap Opening the back up shell. Removing the mold and model.
They should have opened quite easily. Now tap on the mold shell with the palm of your hand or use a rubber mallet, while you pull on the rubber mold. You should be able to pull the mold out of the plaster shell. If you've done the job properly it will not require great effort to pull the mold out of the shell. This is where you find out how good a job you did at removing the undercuts on the rubber mold. If you have not done a good and thorough job of filling in the undercuts you'll need jack hamers, a tow truck and possibly 3 or 4 Patriot missiles to blast it loose. At minimum you will invent words you previously didn't know existed. You may have to break the back up shell to get the model and mold out.
"Slip Slidin' Away" Getting the rubber mold off the model (use dish detergent)
First remove the board from the bottom of the mold. Slip your fingers under one corner of the rubber mold and pull the rubber off the board. Gently pull the rubber loose from the base
of the model creating a little opening. In Congratulations you have successfully completed the making of a rubber mold and backup shell. This ends part I of starting your own home bussiness. Materials for this project are available at our Sculptor's Place Part II will deal with producing a quantity of molds for mass production.
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Turn
the mold upside down and place a level on top the mold board. Level the mold.
Pack clay around it if you need something to keep the mold level. Now place plaster
strips on the mold to create a foot to make the mold self supporting. Add more plaster to
the entire backup shell and smooth it out.
At this point the model is stilll in the rubber mold. To open the
mold use a mold knife or a chisel. Very carefully drive one of the mentioned tools into
the seam between the two mold halves. Do it at a spot where it will not strike the mold rubber. Pry the
two halves apart.
order to keep the fresh rubber inside the
mold from sticking to itself brush some talc onto the rubber in the gap you have
created between the model and the rubber. Pull the rubber back over itself to get it
off the model. If the rubber does not roll back easily over itself, rub some
dish detergent mixed with water on the outside of the mold, it will then slip over
itself easily. Once the rubber is pulled all the way off, wash it in some warm soapy
water. The first casting in the new mold will further clean the rubber.