Thursday, January 17, 2008

Mold inserts

I mentioned in the moldmaking post that I normally make a rubber insert for my medallion molds so I don't have to fill the cavity with clay. My new batch of rubber reached room temperature last night, so I poured one for the new plaque. [As a side note, you don't want to overlook the "room temperature" part of room temperature vulcanizing (RTV) rubber. Trust me.]

Here is the insert. I'm not especially careful about bubbles when I pour these, since all I need them to do is fill the cavity.



It's kind of fun to see him semi-transparent. They remind me a bit of the beeswax ornaments I saw on a visit the Plimouth Plantation. Too bad rubber doesn't smell like the beeswax!

This is the mold with the insert. All that's left is to box the mold and pour the lid. As you can see, the inserts leave the mold much cleaner than the clay. But mostly they just enable you to make multiple molds more efficiently.

2 comments:

Becky Turner said...

wow I cant believe all the work involved in making a ceramic mold! you know what that rubber casting looks like to me? it looks like a frosted glass plaque! that would be really pretty.... I really would love to have one of my medallions..or Id like to make a new sculpt and have a ceramic or porcelain made of it.. but now I can see how much work it would be.. so.. if ya ever want to do one of mine..lol just let me know!

Lesli Kathman said...

It's not that hard, really. The horses are much harder than the medallions because you have to get the mold lines right. The medallion molds just take time, but they are pretty simple to do.