Models for Resin Molds
I have had a lot of fun exploring different molding options over the last few weeks. After receiving several emails with molding questions, I thought it might be a good idea to ‘start from the beginning’ when it comes to mold making.
When it comes to making a mold, regardless of what kind, style, etc., there is one basic place to start:
You need a model.
Let me say it again.
You need a model.
I get numerous email requests for help with a custom mold only to find out the resin crafter doesn’t have a template. In order for you to mold something, you must have a model. You cannot carve out silicone or create a shape in the silicone without a template.
So how do I find a model?
Almost anything can serve as a model for a mold, especially if we are talking about a pourable or semi solid molding material. Here are a few examples of some materials that are suitable for models: wax, metal, clay, bone, plastic, wood, plaster, stone and other resin castings just to name a few. A note on your model choice, be sure you are not violating any copyright laws. While it’s one thing to mold and recast someone else’s design for your own personal use for a few pieces, it’s another thing to recast something and sell it to others. If you are unsure if your model is legal for you to use, get some advice from an attorney.
So what happens if you have an idea for a mold, but don’t have a model?
You are going to have to create your own. Here are several examples that can help you create a model:
1. Let’s say you want to make a paperweight that measures two inches square by 1 inch tall. See if you can find a woodworker in your area that will cut, sand and polish a wood piece that can serve as the template for your mold.
2. Have a more complicated design? Find someone experienced in CAD/CAM work that can create a wax prototype for you. Wax models are great templates for silicone molds.
3. Good with a computer? There are several online companies that will allow you to upload a design via a computer file that can be printed as a three dimensional object. Do it in something like plastic to easily allow it to become the model for your next mold.
So now you have a model. What do you do to make sure you are successful at making a mold?
1. Build or secure an appropriate mold container for your piece. Empty plastic food containers are a great choice for a mold box. They are inexpensive and generally very flexible. If you are going to build a mold box, make sure all sides are leak proof.
2. If your model is porous (wood for example), make sure you seal it before using it with a mold making material. Otherwise, the mold material may adhere to the model via small holes and make it impossible to demold later.
3. The last step before pouring in the mold material is to cover it with a light coat of a mold release agent. I like to use the Petrolease mold release.
What other questions do you have about finding a model for mold making?