The last post was about setting up the enlarging machine. In video below it gets used for the first time to create the Styrofoam armature for the full size piece. The object is to create a big chunk of styrofoam that’s half an inch to one inch smaller than the finished clay. It’s not an exacting task, but the enlarging machine makes it much easier to get right.
Why Styrofoam? Because with a Styrofoam core, I got away with one five-gallon pail of clay, which is about 65 pounds. I’d guess it would take at least three buckets of clay if it were solid–almost 200 pounds, and it would still need some kind of armature made of pipes, wood, etc.
Lessons learned:
- Use contact cement made for styrofoam. I used Elmers and it was very slow to dry and had to be wired together. Even then, deep inside some of it was still wet when I took it out of the mold.
- The setup needs to be extremely precise. I had a tiny mismatch in the distance between the table axes and the distance between the pantograph and it completely messed up the accuracy until I realized what was happening.
- Next time I think I’ll be more precise with the armature and leave less of a gap for clay. Looking back, half an inch would have been fine.
- The way I’m doing this, the full-size clay is necessary because I’m treating the miniature as a sketch and allowing for significant refinement in the full-size clay. If one went the other way, and made the sketch scrupulously exact, one could skip the clay and plaster use styrofoam alone for the full-size model. In that case, the points use to scale it up would be marked on the styrofoam and transferred directly to stone. If the tip of the target pointer could be heated like a hot-knife it could be very fast.
Next time we’ll use the same process to apply the clay to the armature.
Sculpture Tech 