4 Molding Techniques You Can’t Do with Silicone Molds
Silicone molds have been around for many, many decades. They work if you know what you’re doing. The silicone makes big piles of rubber if you don’t. When I was learning how to make molds it was silicone molds, latex molds (ugh), and maybe some urethane rubber molds. I made a few piles up rubber and lots of mistakes.
So there is a better way for much of your mold making. Below I will talk to you a little bit about some mold making techniques that you CAN’T do with silicone molds.
1.Re-Use Your Mold
I’m not talking about making a second casting with the mold (of course you can do that!). I mean re-use your rubber mold to make a New Mold: Another mold that you’ve never made before. You definitely can’t do that with silicone molds. The silicone molds last forever (or at least for 25 to 50 castings depending on your complexity). If you were a mold making shop, you could invest in a method to re-grind the silicone to add it back into your new batches and hope it doesn’t affect the quality of your molds, but I broke the motor in my coffee grinder trying to do that at home.
So how do you re-use your mold to make new molds? Since this is a ComposiMold reusable mold making website, I’m sure you figured it out: Use ComposiMold.
It melts in the microwave or a double boiler. You make your molds just like you would for silicone molds, except the mold making material solidifies by cooling, not a chemical reaction. You can make 1part molds, 2 part molds, soap castings, chocolate castings, plastic castings, etc…and when you are finished with your castings. Re-Melt, filter the ComposiMold rubber if you need to, and then make a new mold. Or just keep it handy so you can make a new mold later on (keep it covered and it doesn’t have a shelf life unlike urethanes).
2.Fix a mistake
Imagine: you’ve made an almost beautiful mold. It took you days to make because the silicone took a day to cure and you had to make two halves, and you’re ready to make your casting-except you notice a hole. The silicone didn’t fill in an area, or you cut off an area that you shouldn’t have. You might be able to patch that area with care by cutting away the spot and brushing or dipping that spot with new silicone.
Or another scenario, you’ve made a few castings and the molds started to go bad in a couple spots. With silicone, it’s time to make a new mold. Open up your bank account.
Of course, ComposiMold only needs to be remelted to fix. A spot with a hole or bubble in it can be fixed by melting just that area. A heat gun works well, or the tip of a glue gun also works well on the low heat setting. Or re-making the mold is not that difficult if necessary. The semi-transparency also helps to see inside the mold material.
This is also a great way of attaching two different molds together to make a new mold and new shape. For example, a new head for a new action figure. Make the body and then take the head off another action figure and put the molds together.
You can do this to customize the molds. For example, if you were making soaps with people’s names on it, such as for wedding gifts. You could change just the area where people’s names were.
3. 2 part molds with Ease
The conventional way for making a 2 part mold is to build up clay around your master until you are at the parting line. You then make ½ of your mold, flip your master and do the second half. This technique is excellent when you want a very specific parting line that is not straight. Even with ComposiMold, we recommend this technique for many mold making applications.
However, in many mold making scenarios, a flat, or level parting line is needed. Taking the time to build up a clay half is just time consuming. And if you are like me, you usually don’t make it flat so you have a funny parting line path.
So just pour ComposiMold around your part to the location that you want your parting line. Let it harden. And place it in the freezer to make it nice and cold. Spray with a mold release such as vegetable oil. Then pour your top half of the mold. Then cool this side, remelt your first mold, and do that half with the same ComposiMold you used for the first parting line.
The ComposiMold won’t stick together if you keep one half cold prior to pouring on the liquid ComposiMold. The liquid ComposiMold will cool faster than the cold ComposiMold can get up to temperature. This is how you are able to make wax and soap castings with ComposiMold. It freezes before ComposiMold melts (sweet!). The only instance where this may not work is for very thin sections. For these areas, pour only a little ComposiMold on at a time, so that it will cool before melting the thin sections of the mold.
4. Creating a casting from an indentation
This technique is a continuation of technique 3. Use the ComposiMold to fill in an indentation or make a part out of the ComposiMold rubber. Then you make a mold of the ComposiMold after it has been cooled in the freezer, using ComposiMold to make the new mold (get that!?). Use a mold release between the layers and it will separate.
Here’s an example: We were making Halloween chocolates by using a cookie shape, but the cookie tin was too hard and the chocolate could not be removed without breaking. So we poured ComposiMold into the shapes, cooled them, and then used those to make molds in ComposiMold. When making the chocolates, the ComposiMold can be peeled away from the chocolates shapes so they do not break. (ta da!)
Still like your silicone molds? Ok. we’ll compromise for some castings…Brush on silicone molds backed with ComposiMold.
ComposiMold does have some great features, but sometimes you may need a longer lasting silicone mold. The silicone is strong and tough and lasts a really long time. So here’s the compromise:
Use a brush on silicone to coat your master and then use ComposiMold around the silicone brush on material to reduce the amount of silicone you use (save you money!). This way 90% of your mold can be re-used while giving you a mold that you can keep if you want (or at least reduces the amount of silicone rubber that goes into the trash).
The ComposiMold part can easily be pulled away from the silicone to be re-used, while the silicone can be stored away for safe keeping. When you want to re-make the mold, just place the silicone back over one of your parts and pour ComposiMold around it. And you are ready to go again…
So there are the 4 mold making techniques that can save you time, money, and frustration. Please read more ouf our website for more information on how to use ComposiMold. We have a lot more examples of molds and castings made with ComposiMold.
Please let us know what you think and if you have any questions. We’d love to hear from you and see what you create!
Thank you and keep experimenting!