Casting Found Objects

[BeckyH]

I have been making plaster molds of various objects, in the necessary number of parts. I started wondering if ball clay was the best bedding material, or if plasticine or some other material may work better.

Also, any tips on getting the surface of the bedding material nice and smooth. I sometimes feel that cutting keys is superfluous, since the mold itself is so bumpy that is registers perfectly well without them.

Thanks!

[Denice]

I have been making plaster molds of various objects, in the necessary number of parts. I started wondering if ball clay was the best bedding material, or if plasticine or some other material may work better.

Also, any tips on getting the surface of the bedding material nice and smooth. I sometimes feel that cutting keys is superfluous, since the mold itself is so bumpy that is registers perfectly well without them.

Thanks!

 

 

Becky I would stick with the ball clay it's easier to work with and less expensive. I have used plasticine to make small detailed sculptures with but still used clay for bedding when making a mold of them. With summer coming soon another thing to consider is that plasticine gets warm and soft fast, I had to keep putting my sculptures in the refrigerator because the heat from my fingers were softening them. I too have thought that cutting the keys at one time was superfluous until I tired it without cutting the keys. It was harder to keep the mold in the right position the lumps allowed the mold to slip, while the keys held it in check. I don't make that many molds any more but I keep a bucket of scrap clay around, it can be different cones and colors mixed together. You can reuse you bedding clay for more molds until it gets to grubby but nothing else. I can never tell when I a whim hits me to make a mold for a project. Denice (Wichita, KS)

[Marcia Selsor]

I have been making plaster molds of various objects, in the necessary number of parts. I started wondering if ball clay was the best bedding material, or if plasticine or some other material may work better.

Also, any tips on getting the surface of the bedding material nice and smooth. I sometimes feel that cutting keys is superfluous, since the mold itself is so bumpy that is registers perfectly well without them.

Thanks!

 

I agree withDenise. plasitcene is great for clean plaster molds but is expensive and has some draw backs. I use my stoneware or smooth raku clay for making molds. I also use murphy's wood soap for mold release on found objects. I think we did a long discussion on this a few months ago.

Marcia

[BeckyH]

Thanks for input. I do reuse my clay, and Murphy's soap is a great mold release.

I'm going to try building the bed and smoothing it before I put all of the framing in place. I suppose I could sand down the first pour before making the later pours. It will just require care to not make undercuts.