Next week we will be casting the weights for our Structural Strength competition. We are going to cast items that you bring into class with the casting method you choose. The method will also be largely informed by the object that you would like to cast.
The most simple way of casting is to cast the negative space of an object directly, this can be a latex glove, ballon, bag, cup, or any type of container that is hollow. Keep in mind that you will have to remove the casted mass from the object, so you might want to use something disposable and easily breakable.
Another simple method to cast is to create a low relief impression of an object on a plastic material such as clay or play dough. This is a fairly low cost method to cast simple objects that have a flat surface.
Another material that is good for casting in this method is alginate. This is essentially an algae compound that becomes a gel fairly quickly when exposed to water. This material is used in the dental industry to make impressions of patient’s mouths, some of you might have experienced this method before. This compound is great for getting a very detailed mold and it’s completely safe for using on the body. However, it is much more expensive than clay.
Molds of whole objects can be made with rubber epoxy mixtures, such as Smooth-On products. Epoxy means that it has two parts, a resin and a hardener which is a catalyst and makes the solution harden into place. These are also more expensive than clay, but you can get some very detailed results from all angles. For this method you might also want to bring a knife and some rubber bands to hold the mold together while you pour your substrate and wait for it to cure.
More complicated molds take a long time to make, because there is a lot of waiting time for the materials to cure. I would recommend that you pay attention to the amount of time that the mixtures need to fully cure. Keep in mind that we have 3 hours to make the mold and let the plaster set.
The mold below has various layers, the green material is a flexible silicone that takes a detailed impression of the object. Flexible casting materials are very handy because they be bent to remove the cast object. This also makes it less complicated to cast intricate shapes with overhangs.
Make sure that you bring:
- A container to mix your materials, this can be a plastic bucket or something smaller.
- An object of your choice
- A casting material of your choice, e.g. plaster, concrete, resin, jello
- An impression material, e.g. clay, play dough, alginate, fast curing silicone or rubber epoxies.
- Other optional materials that will depend on the method that you choose to embark on could be: a knife, rubber bands, cardboard, tape, a mixing stick, etc.
Here are some places where you can find these supplies:
- Home Depot
- Most Art Supplies stores
- The Compleat Sculptor in Manhattan, this is my top choice because they have a wealth of casting materials of different varieties and a very helpful and informed staff.
Email me if you have any questions.