World's easiest silicone mold.

Picture of World's easiest silicone mold.
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:
  • water
  • blue dish-soap (any brand seems to work)
  • 100% Silicone (do not buy quick set silicone, you need 100% silicone)
  • bowl
  • caulking gun
  • something you want to make a mold of.
  • scissors/knife
  • masking tape - to patch holes in your positive, if necessary.
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Step 1: Make your catalyzing solution.

Picture of 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.

Picture of 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.

Picture of 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)
jsrubianoch2 months ago

Is this food safe? I would like to make a mold for making candy lego.

jerrycwood2 months ago

Is there a limit on the thickness of the mold walls? I know that most tubes of silicone say to not exceed 1/8" thickness. Will this technique permit thicker walls?

tubaska2 months ago

thanks, Audrey.

can you tell me how to make right and left direction molds from an object?

eg, if I have a right facing giraffe, how do I make a left facing giraffe?

again, thanks for sharing, tubaska

audreyobscura (author)  tubaska2 months ago

Are you needing to make a 2-part mold?

it can be 1 or 2 part but I prefer 1 part as i'm using the pieces as cabs for my jewelry.

thanks, tubaska
kpsmree3 months ago

Done this today. I'm still waiting for it to set. How long will it set? I did full object (chicken) mold. I'm planning to use clay afterwards for my chickens. Hope it will go all well.
*fingers crossed

audreyobscura (author)  kpsmree2 months ago

Awesome! You should share with the I Made It Button!

maryd623 months ago

hi i need to make a silicone mold thats crystal clear. the objects i insert into the resin needs to be precise. what brand would i use. The mold needs to be as clear as possible. Thanks

audreyobscura (author)  maryd622 months ago

I don't think this method would work. All the molds are typically cloudy.

motleyjust2 months ago

Why does it need to be blue dish soap? Is there a particular ingredient in it that isn't in other colors of dish soap?

audreyobscura (author)  motleyjust2 months ago

No particular ingredient, it's just a way to visually measure concentration of the solution.

MicioGatta2 months ago

Great tutorial and great idea, I'll try it :)

maryd623 months ago

Hello, thanks for this, I need to make a crystal clear mold. Is this possible with that certian brand silicone?I need to place objects in the resin very precisely, so i need the mold to be as clear as possible. thanks

dhooey halim4 months ago
Please make an instructive on how to make the full 3-d object.
gtoal1 year ago
Read the "oogoo" articles on Instructables. They'll show you how to use corn starch (aka Talc, as currently formulated) to cure the Type I silicon far faster.
absomagic gtoal7 months ago
Yes but I have tried both methods and found that the corn starch is much trickier. It rapidly hardens and was difficult to work with on ensuring it was pressed well into detailed sections ( such as the teeth others have talked about). Using this method allowed more time to work with the material and gave great detail in the mold.
paqrat2 years ago
This is way cool. Have you tried it with the white silicone caulk?
I have. It... didn't end well. The pigment in it felt like it was burning my hands after I started pulling it out of the soapy water. I'd stick to using the clear.
Back when I had aquariums there were some folks making their own aquariums and someone said you didn't want to use some of the bathtube silicone caulk cause they have some sort of fungicide in them to prevent mold in the caulk. That may be what you felt on your hands.
Rubber gloves... problem solved!
I've had issues with the silicone sticking to gloves and generally becoming a huge mess. I suppose "huge mess" is better than, "it burns!", but I always preferred the greater dexterity.
Absolutely. These are chemicals. Soap removes the protective layer of oil on your skin, allowing the chemicals to penetrate your skin and cause potential harm, perhaps including nerve damage. I worked every with silicones for ten years, and have been given this info as professional training. Please, protect yourself. I know that sounds like your mother... there has to be a better way!
I think the safety issue is an important point an well made but it is also worth reminding that the silicone mix we are making will stick to silicone. I have used large quantities of this mix and tried to use a large silicone spatula to assist me with the mixing and of course I've still got mixture firmly stuck to it. However the cheap rubber gloves available in uk thrift stores don't stick at all.
Rubber gloves wouldn't stick to the silicone caulk?
It needs to be 100% Silicone caulk, aka "the clear stuff". Most of the other Silicone's actually have latex and other additives mixed in and don't work well at all. Plus, they are more expensive.
That's important enough you should mention it in the 'ible itself!
absomagic paqrat7 months ago
I had trouble with white silicone but great success with same brand grey silicone!
audreyobscura (author)  paqrat2 years ago
I haven't - if you try it let me know how it goes!
I think I have some white silicone tub caulk. I'll check it out and may try it this Sunday.
paqrat paqrat1 year ago
Turns out what I have is latex. I'll try picking some up though next time I hit the store. I think I'll stick with the clear though.
AudreyObscura(CoolName!): To add to your great guide: A neat trick I found online a few years ago, is to add a few drops of Acrylic(!) hobby paint( about 2-3drops per dixie cup of silicone caulk ) and mix well. The Acrylic paint also acts like a nice colorant and mix indicator, but it's water contents causes the silicone to cure solid throughout the mold like regular 2part molding compounds. I think this is what the soap is also doing.

I've used this to make custom insulators and rubber-Sugru-like items. If you want a courser texture add a little cornstarch. -Lee Studley
rauthbert8 months ago
i did this using liquid glycerine (not sure if theres any other types)
but it was super sticky when handling it, should i put in more or try a glycerine based dish soap instead?

thanks in advance =]
I have had the same trouble with some 'so called' silicone products. I suspect what you tried it is not close to 100% silicone.
Smalfrii7 months ago
this is perfect! thank you so much for posting this! i had already tried using this fancy mold making kit, but it failed miserably. Never cured. i can finally finish my project and post it :)
Great work, saved the PDF for future use. I made some oogoo once with red silicone (heat resistant for engine seals) and talc, only a small job and it worked great once I added the right amount of talc. Have to try water as a catalist. Thanks.
Late reply here... corn starch will harden silicone, as it holds a lot of moisture. Add enough to make it a manageable paste and it will harden very quickly.
If red silicone is heat resistant could it be substituted for the clear and then fired in and thus create a mold that could be used in an oven at 400 deg? Debbie N
spider878 months ago
Thank you so much this is exactly what I've been looking for!! I'm with JHarris67 going and buying molding stuff from michaels seemed like the only option but seemed cost prohibitive!
jharris678 months ago
that is AWESOME! thank you so much for this! I've been mulling whether I wanted to spend $20 to buy molding materials from Michaels.
maggiemul10 months ago
Does any1 know would you be able to use this to make a mould of your hand by adding a release agent to the hand? I need to make reusable moulds of hands?:)

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