Saturday, August 21, 2010

New Materials and Molding Techniques












New Materials And Molding Techniques by Kristen Strand-Tibbitts

The picture on the left is the original 30 inch prototype Laura doll. The picture on the right is the Hydroshrink cast of face portion of Laura from the waste mold
The picture on the left is the Hydroshrink heads after dehydrating and shrinking for 6 days. The picture on the right is one half of the mold created from Compsimold-LT
This article is not exactly related to Softies, nor cats and dogs. Although I would argue you could use some of these molding techniques to create molded felt animals like R.John Right!

I attended a private class at Gail Wilson’s workshop in Acworth New Hampshire this spring, where my goal was to learn how to shrink a sculpt, create molds, and refine a doll design. The doll in the above picture was sculpted in earthenware clay, and a plaster waste mold was produced. I poured the head in liquid papermache (FLUMO) , added sculpted hair, and painted her in oils. I always like this doll, and call her Laura. She is about 30 inches tall but not my idea of the ideal doll because she is too large. Also since I was focused on making a pretty face, I did not have any plan on how to attach her head or create a body. I was interested in learning how to shrink down a sculpt, and refine some of my mold making skills and get an overall doll design, for the new and improved Laura doll. We agreed to break this into several sessions, with the first step shrinking down the doll to be about a 15-16 inch doll.

The initial plan of action was very traditional. We could make a putty mold of the Laura doll head, and pour the head in wax. This two part putty mold is a quick and easy method to make molds from originals. It’s a flexible material so its other advantage is you can unmold something with undercuts like Laura’s hair I purchased the putty from http://www.alumlite.com/ . This strategy would be to use the putty mold to cast a wax head, while solidifying, it would shrink a bit, and then one would create another waste mold in plaster and then repeat the process. Gail calculated we would need to do this 5 times to get a doll of about 15-16 inches. However polymer chemistry save the day, and Gail identified a new product called Hydroshrink (http://www.sculpt.com/) which when poured into a mold, the item will shrink 51%. This implied we could do the shrinking in one step!

I had a plaster waste mold of the original doll, which we could cast in Hydroshrink, but I also had a porcelain head that I poured and fired from the original waste mold so this head was 16 % smaller than the original. We decided we would try both, so as to increase the odds of getting a head the size we wanted.

We needed to make a mold of the porcelain head, and here again Gail found another miracle material. We used a product called ComposiMold-LT (http://www.compositherm.com/) which is a hard gel like substance that you can melt on the stove or microwave, and in its hot , liquid state use it like plaster to make molds. The advantage of this material is it is easy to use, and can re-use this to make additional molds. I just cut it up , re-melt, and reuse. So this composi-mold when cooled was used to cast another Laura in Hydroshrink. As it dehydrates and shrinks, it becomes a transparent yellow-ish color. The second photo shows the Laura faces after a week of dehydration and shrinking. According to the website, dehydration/shrinking can take up to 14 days.

So early this summer, my heads have shrunken, and I made putty molds with a product you find here: http://www.alumilite.com/ProdDetail.cfm?Category=Silicone%20Rubber&Name=Mold%20Putty. This stuff is pretty good for a starting point to impove a figure, but you wouldnt want to use to cast doll parts. I poured the putty molds with Medium Firm sculpting wax purchased at Willow Products, attached each side by slightly melting the wax with an embosing gun, and pressing together . There were a few rough edges to smooth, but all in all it looks good. The last images shows wax doll with sculpted in using a softer was (Ether) sold at Willow Products (http://www.willowproducts.com/) .




Currently I am trying to figure out what size arms and legs go with this head. I will try to keep you poseted