All You Need to Know: Molding With Silicone

About: I'm a nerd who loves to geek out with makeup. And books, series, movies, you know.

If you're doing any project that will need a mold that is flexible, then you gotta work with silicone. You can use it to cast sculptures, props, and even makeup prosthetics!

So I’ve decided to create a post exclusive to explain how to work with it, following the motto: No need to waste product.

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Step 1: Mix Before Use

Everytime you open the bucket of silicone, it’s necessary to stir it throughly. Silicone can cure with contact with air, and if you only use the first layers of the silicone on the bucket, the product that is on the very bottom will eventually cure inside.

Mind you, even with you mixing properly, once you've reached the end of a bucket you may notice that it has thicken. So make sure you close your lid extra tight, and keep mixing it before use.

Step 2: Work Within the Expire Date

As I said in the last step, the silicone will start to cure by itself, so the longer you have the bucket sit in your shelf, the most likely is that the silicone will thicken.

You can still work with it, however, it’s more likely you end up having air bubbles, and worst, not reach all the details of your positive.

Step 3: Catalyst: What It Is?

This comes with the silicone, and it works as an agent to speed the curing process. Usually each silicone will have it’s proportion of catalyst & silicone, along with a time sheet. Usually the more catalyst you use the faster the silicone will cure.

Step 4: How to Avoid Air Bubbles

There are several ways to avoid air bubbles, and I will list a few (all this already with the catalyst mixed):

• Hit gently the container you have your silicone mix on the table so any air bubbles can float to the surface;

• Put the mix inside a pressure chamber so any air inside can be "pressured" out ;

• Pour the silicone from a decent height so it can fall in a thin string on the mold, and let the natural fall fill the mold;

• Use an airbrush to hit some air on top to kill any air bubble;

• Hit gently the mold constantly to let the air bubbles to float also.

Step 5: Cabosil

Did you know you can thickener the silicone using cabosil? Yes, it’s possible.

Not all silicones can be used using it, but those that can, this is a great option! Mainly because by thickening the silicone, you end up not using as much product you would use if using the silicone by itself!

However I do need to remind you to not use this mix as the first layer, directed on the positive, best to put it starting on the second/third layer, depending on how thick your first layer was.

On a last note, you MUST wear a dust mask to work with cabosil! Because the fumed silica can be breathed, and will be stuck on the lungs. So don’t forget about safety!

Step 6: Saving Every Last Bit

This is a trick that not only will prevent you to have any waste, but also will help you use less silicone! Do you know those pieces of molds you won’t use? Could even be the silicone that cured in your cup after pouring all on the mold.

Well, cut them into tiny pieces, and when you have a mold with some extra area, you place these pieces between the layers of silicone. This will create the necessary volume to fill the whole mold without you having to use as much silicone as you would!

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Laura x

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