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Picture of World's easiest silicone mold.
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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.
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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.
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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.
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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)
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icarusmed3 days ago
Hi there! Great idea and great instructable!! I've got two questions for you. First of all, you said it's clycerine the catalyzer. What if i use pure glycerine?? Aaaaandd... Most important thing.. Could common silicone be used to cast Silver?

No, the silver would have to be to hot for the silicone. Silicone can cast things at temperatures around 200c. Silver melting point is like 800c or something high like that.

yediknight9 days ago

Great idea! Where is the second half of the mold, did I miss it or does Glitter-Trex have no tail?!

d124c015 days ago

Could I mold a full object and then cut it in half with a exacto knife?

jessicavda1 month ago
Hi, thanks for this.
i'm trying make a mold from a marble.
Would it be possible to do this in one piece?

Thanks
lovethepug1 month ago

I tried this just the other night for the first time, it worked great!! It came out just like it said. Now I am having a problem coloring the resin. I bought the darkest color specifically for resin and its still too light. It gave me a baby blue and I need cobalt blue. How much of the coloring can I add before I mess up the resin? any other suggestions for alternative coloring methods?

Hi! I love this. Thank you! I am making a two part mold and the first piece is done and dry. I am using vaseline in between to keep them from sticking. Can I use the same dish-soap catalyzing bath from the first part, or do I have to make a new batch for another. Thanks so much!

simonsch4 months ago

Great post! I have used this mould making technique many times so I thought I would contribute a few tips of my own. Acetic cure silicone will cure much faster that neutral cure. for speedy results use acetic cure. I would recommend a coating of soap on the hands before plunging them into the water/soap mix as the silicone can still be a bit sticky even in the soapy water. Also too much soap in the water can cause the silicone to become lumpy and not consistent. This water curing technique can also be used for direct modelling of silicone sculptures.(see photo) I usually make the sculpture in small parts and then join them together at the end. Silicone can easily be coloured for this by adding oil paint. For those commenters wanting a two part mold using this technique, build a clay barrier to seperate the halves, same as all two part mould making, and a good wax based release between the silicone halves so they don't stick together. Cheers, great instructable.

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quirxi simonsch1 month ago

Woow, cool dino !

BMm12 months ago

im a girl and i just want to ask if is it safe to make something penetrative (if you know what i mean) out of that 100% silicone?

Hitlist BMm11 month ago

go for it if you don't have any silicone allergies. Need a model? LOL

audreyobscura (author)  BMm12 months ago

Hey there - i feel like this is the question i have been waiting for since I published this Instructable. I'm pretty sure that this 100% silicone off-gasses acetic acid as it cures - it would just need to be neutralized before....well. have fun!

thank you for the reply, one more thing. how can I nutralized it?

audreyobscura (author)  BMm12 months ago

http://www.smooth-on.com/Silicone-Rubber-an/c2_1115/index.html

audreyobscura (author)  BMm12 months ago

Maybe a baking soda bath? But this isn't medical grade tested - I would pursue further education about materials that may not irritate your skin. Or do some patch testing on your wrist of a neutralized cured silicone, at the very least.

85rocco1 month ago

I've messed around with silicone caulk a bit myself and if I understand the chemistry correctly, silicone caulk cures in the presence of moisture, normally it's atmospheric moisture that cures the silicone from the outside inward but anything you add to silicone that can carry moisture into the silicone will make it cure. I've used corn starch for this but anything that retains moisture will do, a small amount kneaded into the silicone will cause it to cure en mass the same way it does with this soap and water trick.

shep621 month ago

Hi, When I was working in the pharmaceutical industry one of the materials we were handling was proteletic enzyme, this was used in a product that was designed to remove dead tissue around wounds which it did well but we had the problem of it digesting our top layer of skin even with all manner of gloves. Then we had a visit from a rep selling a special barrier cream. He said it would act as a barrier for most things, his demostration was to apply this barrier cream onto his bare hands and then pour Sulphuric acid over them! This was concentrated acid provided by our labs. The demo worked with no evidence of any acid burn to his skin. We purchased this barrier cream by the bucket load and never had any problem with loosing our skin to the enzymes ever again. Sorry about the long amble but there are barrier creames available for many differnet requirements. No gloves and the silicone would lift completely from the cream on the hands when washing hands after work.

MeganC21 month ago
jcurtacci1 month ago
so the silicone will not hurt the paint of the item?
just sayin1 month ago
Can you use this for chocolate or liquid sugar? You know.....to make the chocolate ,etc have a shape
rbloom2 made it!2 months ago

Thank you so much for this. I had ordered a prop that used the same gem featured in my pictures and it was a mess. I am sure that with your technique I will be able to create something much better. Thank you again! Also love that Jesus clone he's gorgeous! (Or she, is that frog DNA?)

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audreyobscura (author)  rbloom22 months ago

Thats fantastic! I am going to give you some pro-membership for folliwng this Instructable, and using the "I Made It!" Button.

Cheers!

Audrey

judy726492 months ago
Can you use it on a horizontal surface? I have a pattern on my fireplace I'd love to make a copy of.
audreyobscura (author)  judy726492 months ago

I learned this technique when I was trying to replicate a motif on a tile in my old apartment - so yes! you can! just figure out a way to get the silicone to stay horizontal, Gaff tape worked ok.

I see you were able to cast the entire dinosaur. How did you do this if the mold was only for half of the dinosaur? Great tutorial!

audreyobscura (author)  mckinley_freeman2 months ago

I actually missed the whole back part of the dino - it was only a one part mold. You could make a two-part mold using this technique though.

squirejoe22 months ago

Instead of dish soap, why not just use pure Glycerin. You should be able to find it in any Drug Store?

brown682 months ago

i advice you not to use on skin or (especially) anything penetrative, i"m an artist and did many casts out of body parts which in such case i used alginate which is extremely safe and the results are super fine detailed.

BMm12 months ago

I tried to handle it and even putt some small amount on my arm while it is wet, nothing happened. but Ill tr to look for some food grade silicon I think that's much safer :)

CarolineK22 months ago

Can you used water based clay for making the original for this? If so, will it need a release and should it be wet or dry when making the mold?

IamTheMomo2 months ago

Can it be extruded? I have some small decorative glass bottles that I like to keep vanilla and other extracts I make in, and I can't find corks to fit well. I'd like to extrude a cylinder that would fit in my bottles, then top them with something larger, such as a button or glass marble.

BMm12 months ago

how about putting something hard inside it?

kelli19632 months ago

it-notwanti=to-harden

timevortex2 months ago

how would/could you cast the whole figure at once?

Cannot wait to do this!

USE RUBBER GLOVES - THE SKIN ON MY HANDS PEALED WHEN I DID THIS THE FIRST TIME - NOT FUN!! COVER THE GLOVES IN THE MOLD RELEASE.....

i dont think that is a normal occurrence maybe get it checked out. depending on the kind of silicon you used it could have dried to youre hands and that is what you saw

The acetic acid in the silicone is burning your hands as it cures. Wear gloves as I heard that your skin absorbs up to %20 of what it touches.

amvancourt3 months ago
I've always used Oderless Mineral Spirits and/or WD-40 to clean hands of residue. Bonus tip: Do not smoke.

thanks! And that's always a good tip! haha

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