Further Experiments with Alginate

Before we could go for the torso cast, which was our next goal, we needed to prove that we could bond alginate to itself.  Once this material sets, any additional material will not lock into the stuff that set before it.  We learned previously that we could only cover a limited area with alginate and get it thick enough to work well during casting.  But if we could put a thin layer of alginate on, let it set, and then follow this layer with another application of alginate, we could have both coverage and thickness.  So we would have to bond the second layer to the first.  We have an alginate bonding agent, but were experimenting with it for the first time.  Dissolved in warm water this solution would be briefly sprayed on set alginate.  The surface is then wiped with water and patted dry.  Thus prepared, the set alginate will bond with a subsequent application of the mold making material.

To test it out we put a thin layer of alginate on a bottle to make a print coat.  This would be a thin layer whose purpose would be to take a faithful impression of the bottle's features.  We then treated the set alginate with the bonding agent, followed by a thick application of alginate as a second coat.  We had problems with the mold that resulted in a somewhat mangled cast, but the experiment worked.  The two layers of alginate held together well.  We now knew that with a larger mold we had the working time and coverage ability to achieve our goals.

We were ready for the big cast.