Archive for November, 2010

Silicone Casting part 3

November 24th, 2010 admin No comments

We started trying to take a resin cast yesterday. It was probably too cold for this, and I’m pretty sure it will be unusable. Either way, pictures!

Mold pulled from clay mask

Slush Casting test 1

Categories: Doctor Who, General Tags:

Silicone casting part 2

November 23rd, 2010 admin No comments

So we skipped the large scale tests, and moved directly to the real thing, mostly because we’re running out of time (we’re shooting to have this done by Saturday – this molding takes place on Monday). So far, we have applied two layers of the silicone mixture (3:3:1 – silicone:mineral spirits:corn starch), the first layer tinted so it can be cleaned of the white clay more easily. This was all cured after 4 hours (probably less, but we played it safe), and we peeled it off to check how we did. Not bad! We found a couple air pockets that were probably due to not mixing enough goop for the first layer, and thus having to do it in two batches, but I think those will be easily corrected on the casting with a little sanding. Then we put the mold back on the master and applied a few layers of plaster bandages to make a mother mold. More pictures to come.

Mask sculpted by my amazing wife on a plaster cast of her own face.

First batch of tinted silicone goes down - a little short of full coverage!

Two full layers of silicone down

Categories: Doctor Who, General Tags:

Silicone Casting Tests

November 15th, 2010 admin No comments

Three poorly-sculpted clay figures

I’m working on a couple of projects right now where I’d like to be able to mold and cast certain pieces. I found a tutorial for using hardware-store caulking silicone mixed with corn starch to make something called Oogoo in place of more expensive silicone mold-making material.

I decided to test the various methods I found online, to figure out which was best for my purposes. First, I sculpted three very basic objects out of clay, since that’s the material I’d be trying to take a mold of for the real projects.

LtoR: Mixture C, Mixture A, Mixture B

I prepared three mixtures (all measurement by weight):

A) Straight-up silicone from the caulking tube

B) 1:1 Silicone to Corn Starch

C) 3:3:1 Silicone to Mineral Spirits to CornStarch

Results were as follows:

A) Took forever to set-up. When last checked, it has not fully cured (~9 hrs).

B) Very thick and sticky, but set up very quickly (<2hrs). Difficult to get good detail due to thickness and stickiness.

C) WINNER Very pourable, and cured in <4 hrs. Seemed to pick up all details. This is the one I will go with for larger scale tests.

I made resin casts from B and C, but haven’t taken photos of the results yet.

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