World's Easiest Silicone Mold.

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About: I'm a Community Manager at Instructables and the voice of the robot on Twitter! www.twitter.com/instructables Tell me what projects you want to see in our Twitter feed! When I'm...

Yep. That's right. I am about to change your mold-making technique forever. This simple way of silicone mold-making will have you wanting to make casts of all your trinkets and toys.

You will need:

2018 Edit:

If you are looking to use this mold making technique to do life-casting or food casting, these molds are not skin or food safe.

I recommend these kits:

Step 1: Make Your Catalyzing Solution.

By mixing a high-concentration of dish soap with water in a bowl, one is actually making a catalytic bath for your silicone. The glycerine in the dish soap accelerates the cure process for of your 100% pure silicone.

This is by no means an exact science, I use blue dish soap because it allows me to see how much I have added to a water bath, I approximate that I used 4 oz. of soap in 64 oz. of water.

Step 2: Catalyzing the Silicone.

Cut off the tip of the silicone caulk tube, and set it in the caulking gun. Unload enough silicone to surround the desired object, into the bath.

I use the whole tube usually.

Step 3: Preparing the Silicone.

While keeping your hand submerged in the dish-soap catalyzing bath, gently clump the string of silicone together. Form it into a ball, and slowly massage it. Fold it, stretch it out, and work it very much like one would knead dough.

When it begins to become a bit less malleable, and stiffen, it is time to sink your positive into your material. In this case, Mike helped me, and we used his dinosaur, Jesus. (hay-zoos)

Step 4: Make Sure the Mold Is Water Tight.

The best way to make sure your mold is watertight is to add a kind of thick-ish layer of silicone to the surface area of your object. Note how the dinosaur is padded by about a 1/2" layer of silicone all around its body. Also, I have left a considerable amount of the dinosaur uncovered, as I am only casting half of this figure.

You want to make sure you can still wiggle your figure out of your mold, without any of it getting caught, otherwise it can be very tricky to extract once your mold has set.

Step 5: Let It Cure.

It will take about an hour for a full cure of your mold, before you can use it. Allow your object to remain in the mold while it cures. When the mold is no longer tacky to the touch, and feels rigid, gently remove your positive.

We kept this mold on top of the fridge, and put a bit of soapy water down on the plate so that the silicone didn't meld with the paper plate.

Also, this part smells awful. Make sure you do all this in a well-ventilated space.

Step 6: Use Your Mold!

We made a sparkly rendition of Jesus with clear casting resin and glitter. When the resin began to gel we set three LEDs inside of him. Behold the sparkliest light up dinosaur in West!

____

This project uses affiliate links that help me make more awesome DIY projects and tutorials - thanks for your support!

13 People Made This Project!

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432 Discussions

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ViktoriaP

Question 11 months ago

I tried this on a ceramic dish but the silicone got completely stuck to it. How can I remove the silicone? Thanks

3 answers

A single edge razor blade, working against the surface of the ceramic and cutting a bit at a time, then lifting, should free the silicone piece. Patience! and good luck :-)

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audreyobscuraViktoriaP

Answer 11 months ago

Was this an unglazed ceramic surface? The silicone likely penetrated the pores of unglazed pottery. I'm unsure of a way to remove cured silicone outside of brute force :-/

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Mikki G.W

2 years ago

I tried several times to make a mold from a ceramics figurine (unglazed) I made for the project. But the silicone always sticks way too good to the figurine, thus not leaving a very smooth mold. Also very hard to get out.
I never tried to cure it in soap water first, but do you really think that would make the trick? I tried to cover the figurine in oil first, but made no difference.

Now I just have a figurine with a lot of silicone residue all over it, and I can't figure out a way to clean it off efficiently so I can start over

15 replies
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Trent_360_2Mikki G.W

Reply 12 days ago

Lacquer thinner for cleaning. And try putting your item in a condom before covering, leaving the opening open. Let set then pull both condom and item out.

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BrandonG22Mikki G.W

Reply 2 years ago

Ceramic is a pretty porous material, even when glazed sometimes, and the silicone loves to stick to it for that reason. In my experience, using the soap water bath will not change the unfortunate results very much if at all. I don't know a good method of cleaning a silicone stuck figure besides burning the silicone off and I wouldn't advise using ceramic objects for this process, ceramic just doesn't want to play nice with silicone.

If you are still bent on casting it, you could maybe coat the ceramic figure with some sort of resin after it is cleaned to give it a less porous surface...? Something to look into perhaps!

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Mikki G.WBrandonG22

Reply 2 years ago

I'm not too keen on getting it glazed, because I want to keep as many details on it as possible

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KarenW142Mikki G.W

Reply 2 years ago

Hi Mikki! I am an instructor for porcelain and ceramics (35 years) and I tell you that so you know I am not blowing smoke but know the mediums enough to give you help. You can glaze any bisque piece with 2 smooth coats of clear glaze and not lose the detail of your piece. Over coverage is where most folks lose some of the details but you will never be able to get a nice mold from a piece that is not smooth to start with. The mold only replicates what you have, and exactly as it is. You're mold will be so nice once you prepare your ceramic item correctly, and your pieces you pour will too! Good luck!

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NDSunshinesamd115

Reply 10 months ago

I have worked with silicone on home repair projects. when I want it to stick to one surface and not an adjoining surface, I slightly, very slightly dampen the surface I don't want it to stick to and powder it with baby powder. This works when you are laying down a bead, but if you move the work too much, the silicone will absorb the baby powder. Otherwise it works great.

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ThomasV127samd115

Reply 12 months ago

If you you go through this instructable you can use the mixed whater+soap as release agent. I tried and it released easy.

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hettyeKarenW142

Reply 11 months ago

Would that work with a spray on clear glaze as well?

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DrRadiumMikki G.W

Reply 2 years ago

Actually, you don't have to glaze it. SuperSeal from Smooth-on seals porous surfaces and is specifically made for this purpose. It comes off with warm water.

https://www.smooth-on.com/product-line/superseal/

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Bald headed ho BrandonG22

Reply 11 months ago

Try melted wax to coat the positive. Use a heat gun on low then wipe clean with a cloth

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XTLMikki G.W

Reply 11 months ago

You can use vaseline as a separator. Smear it on and then use a hair dryer to warm it up - this will remove (melt) the finger marks and excess away. Use it thinly. Let it cool and "dry" before applying silicone.

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SherryP34Mikki G.W

Reply 1 year ago

There is something called mold release that you spray on your original piece so it won't stick. I know the Smooth On company makes one, but there are a lot out there.

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GintareCMikki G.W

Reply 2 years ago

If you need to remove silicone from a surface, the easiest way is to use
white vinegar. I used it to remove special mold-making silicone, should work
for this cheaper version as well. I haven't tried it on ceramics, so do a test clean on a sample just in case.

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MaryW145Mikki G.W

Reply 2 years ago

Mikki the trick to it not sticking to your ceramics is it needs to be a glazed piece. Not sure if you are using a bisque or plaster piece but it needs to have some kind of finish on it. Hope this helps.