Introduction: Make a Silicone Mold From Common Household Materials in Your Kitchen in 1 Hour

Picture of Make a Silicone Mold From Common Household Materials in Your Kitchen in 1 Hour

Taking off from this BRILLIANT 'ible I have started making silicone molds on the cheap and thought I would share. This is incredibly simple and fast and can be used for a ton of casting ideas...

Here is the podcast I did on it:

The basic instructions are below....

Step 1: Materials

Picture of Materials

You will need:
  • SIlicone Calking (the stuff that stinks like vinegar or acetic acid) I have a calking gun but you can get smaller tubes of it at the hardware store
  • Mineral Spirits (this is just paint thinner but somewhat less toxic than the rest. NOTE: you can use white gas or camp stove fuel but be CAREFUL if you do use that. The advantage of white gas is that it will cure the mold faster and the mold will not smell like mineral spirits after)
  • Corn Starch
  • Vaseline
  • Latex gloves (or what ever kind you like)
  • mixing sticks
  • Drill
  • Bent nail
  • Something to cast or mold
  • Small box
  • Mixing cups
  • Wax paper
  • Play dough

Step 2: Prep the Item to Mold

Picture of Prep the Item to Mold
  • To prep the item for the mold cover it with Vaseline (if it is a bit goopey use a blow dryer to melt the Vaseline and smooth things out).
  • Next cut the bottom of the box out and place it on a piece of wax paper
  • Get some play dough and fill the bottom of the box with a layer thick enough to cover half the figurine (don't put the figurine in yet this is just setting up the base
  • Press the figurine into the dough and make sure to cover 1/2 of the figure
  • Vaseline the dough and the figure (if it is a bit goopey use a blow dryer to melt the Vaseline and smooth things out).

Step 3: Make the Mold Material

Picture of Make the Mold Material
This is where the coolness happens...
  • Mix a 50/50 mixture of Silicone Calk and Corn starch in a cup
  • Add some mineral spirits (or for those pyros out there white gas). You need about 25% of the volume of the 50/50 mix of silicone and corn starch
  • Mix with your handy dandy bent nail you chucked into the drill!
  • Add more mineral spirits if you need to to get the goop to flow
  • Pour into the top of the mold base you made in the last step
  • Get on to the next step before 5 min is up!!

Step 4: Pour Thinned Oogoo Into the Mold Base

Picture of Pour Thinned Oogoo Into the Mold Base
  • Pour the mixture into the mold base and level it out
  • Place mold under oven hood (running) to gas off and not fumagate your house
  • The mold half should set in about 5-15 minutes

Step 5: Next Half of the Mold

Picture of Next Half of the Mold
  • Flip over the mold and peel out the play dough
  • Cover with another coat of Vaseline (make sure to get all the silicone that has set up)
  • Mix another cup of the Oogoo
  • Pour
  • Smooth
  • Let set...

Step 6: Home Stretch!

Picture of Home Stretch!

Let this sit for about an hour to set up fully under the oven hood. We can now peel the bad boy apart.

Test the mold with some play dough by pressing it into the mold and seeing what comes out

Keep in mind the mold will stink like mineral spirits for about a week so let it gas off out side or in your shop. Otherwise use white gas it is much more dangerous (i.e. flammable) but makes a quicker curing mold that does not stink as much.

The mold will shrink about 10-15% after cure FYI

HAVE FUN and make sure to watch the video to clear any confusion up. There are more videos like this at or join our facebook fan page at


tablet1 (author)2017-02-22

I made one side of this mold but this is wet after 24 hours i cant start another side

Malicity (author)2016-10-18

Has anyone tried using water based caulk for this sort of thing?

printrbot932 (author)2016-04-07

How much more will it shrink with 50% of volume mineral spirits

treymartin82 (author)2015-12-25

What temperatures can these molds with stand?

cashfl made it! (author)2015-09-19

If anybody is going to try something with a lot of contours, I suggest doing a thin primary layer and lightly pressing in some burlap from the hardware store, and then adding a thicker layer later on; the burlap will get the next layer of silicone to bite an hold on and during the initial layer, it will keep the silicone in place (basically put a little circle of material on a section, place a light about of burlap and continue until whole this is a layer of silicone with patches of burlap.

C Diane (author)2014-04-27

I tried using 50/50 silicone and cornstarch since I wanted a more clay-like consistency to mold over an object. The stuff never dried and had to throw the whole thing away. I used GE premium waterproof silicone for kitchen/bath/plumbing (100% silicone and regular corn starch. What did I do wrong?

ThisIsMyNameOK (author)C Diane2015-09-04

GE silicone will work, but only the GE 1, which is clear and smells like vinegar. It sounds like you used GE 2 or 3, which have different ingredients and will not work to make Oogoo. If you haven't done it yet, have a look at the original Instructable.

CptanPanic (author)C Diane2014-07-12

ge silicone is different and will not cure the same with corn starch. you need to use regular silicone that smells like acid.

rlyndallwemm (author)2014-10-10

Forty dollars worth of failure. Probably because the State of California does not sell proper Mineral Spirits. The first batch was too thick to pour. The second was better. None of it stuck to the item properly and just fell off it, distorting the pour box and pushing out the sides. Horrible expensive mess.

There are lots of other options for thinners. Take a look at the original 'Ible, and some of the others. Mikey77 prefers Naptha, if I remember correctly, and it seems acetone also works well, according to comments here. I would also recommend starting with a much smaller project so it won't be so expensive. I am planning to conduct my first Oogoo experiments later today or tomorrow, but only 1 Tbs at a time, until I find what works the best for me. That way it won't cost me any more than about $5 to try all the different mixtures possible.

Also, make sure you are using the right caulking. It only works with the clear one that smells like vinegar.

JohnLThornton (author)2015-03-26

Thanks for posting this Instruction. I made it! Not a Play-dough toy, but a mould of an essential - and
tiny - part of my wheelchair, which would have cost hundreds of pounds
to replace (because I would have had to replace the entire footrest
system, even though only one tiny bit snapped off).

I found that
the best place to get right silicone is at the cheapest stores (in the
UK that would be Pound shops or Wilko). The posher shops sell upmarket
stuff which doesn't have the vinegar smell.

When doing my initial
test, the only alcohol thinning liquid I had to hand was Nail Varnish
Remover (an essential part of my tool box because I'm constantly glueing
my fingers together whenever I use SuperGlue!).

I needed to use only a few drops of the Nail Varnish Remover, along with a teaspoonful of cornflour and a teaspoonful
of silicone caulk (the caulk I used for my initial test had been open and sitting on my shelf for
several years).

The mould dried fully within a few hours and it worked
beautifully. Now I've got the bug I'm going to try and make a mould of
my favourite Buddha statue.

That is really cool. The best and most practical use for Oogoo that I have read about to date. And it's good to know that the nail varnish remover/acetone works because I forgot to buy mineral spirits when I went to the store for supplies yesterday.

I don't think dollar stores here in Canada carry things like silicone caulking, but I'll have to have a look and see, since it is a little pricey at Walmart and I have a lot of ideas for what I want to do with it. Thanks for the tip.

Oh, I forgot yo say, I keep the nail polish remover handy for the exact same reason. Have never managed to super glue anything yet without gluing myself in the process.

I never thought of nail varnish remover (here it is nail polish remover) Given you need less volume of it and it smells better in my opinion maybe that is what I should be using. Thanks!

How much mould shrinkage happened using this thinner?

Pure acetone is probably better than nail polish remover, which usually has other things added to it. If I remember correctly, Mikey77 did mention using acetone but said that it smells worse than some of the other options. I don't know, but I have some that I keep on hand for the same reason as JohnLThornton, gluing my fingers together, or to other objects, or both.... anyway, I will give it a try when I get around to making some Oogoo, which I hope to do later today.

AlanS11 (author)MechanicalMashup2015-06-01

Nail polish remover is actually just acetone if you need a larger qty

Given that the piece I was working on was no more than 12mm long, there was no perceptable shrinkage. But you've got me thinking. My Buddha statue is about 45mm high so I'll make a point of measuring the final product and record any notable difference. I think I've caught the bug! ;-)

ThisIsMyNameOK (author)2015-09-04

Thank you for this excellent Instructable. This is exactly what I want to do with Oogoo. At least, one of about 50 things I have thought of so far. And thanks for the tip about using the oven hood. I really need a way to be able to work with it indoors, since I live in Canada and, to coin a phrase, winter is coming.

cashfl (author)2015-08-25

My two cents:

1) My proportions: By volume: 1 part caulk, 2 parts mineral spirits, 2 parts corn starch.

2) I strongly suggest that you steep the caulk in the mineral spirits for at least a couple of hours or overnight even. I've been casting large head and it was a nightmare trying to do it off the bat; not even one of the large mixing its you use for drills would work until I had let it dissolve some..

3) A drop or two of glycerin from the drug store will insure gelling.

4) As has been noted, the GE caulk is tricky. I've been using the DAP brand with success.

BananaaM (author)2015-07-05

the olny problem is that the thing I am trying to cast is made play dough :(

In this case look up Gelatin Moulds

Antwan1013 (author)2015-04-05

Will this mold work for plastic? I was thinking of recycling my milk jugs to make plastic parts for various things. I am new to this kind of thing so I am not sure if the hot plastic will either melt the mold or even just stick to it.

WeeRedBird (author)Antwan10132015-04-06

You should be able to do it with plastic. Many even talk about casting metal with this mixture.

You can always try using epoxy resin if you don't want get to the high temperatures required to melt plastic.
I've heard of people using a double boiler, the sort of thing you use for melting chocolate, but using oil instead of water for temperature regulation as you need a much higher temperature.

WeeRedBird (author)2015-04-01

Having a bit of trouble with mine. Even though I used Vaseline, both halves of the mould stick together.
Luckily I made a pouring hole at the bottom, so could dig my model out via it.

Any tips? Should I wait longer before lubing up and pouring the second half? Do I need a thicker layer of Vaseline?

SixFootBlue (author)2015-02-08

Are these molds oven-safe? I was planning on using them with polymer clay, and then baking the clay at around 120C while it's still in the mold. Since it's not food-grade, I'm not sure if it would release contaminants or toxins into our oven.

TwylaM (author)2015-01-10

Thank you so much for sharing, and the instructional video was exactly the type I learn with the best, creative, fun, and provides all the steps with hands on visual material! May you be blessed in Christ as this tutorial has blessed me, and beyond.


JosephChanceWatkins (author)2014-11-10

Good tutorial, thanks for sharing; Jesus Christ Bless you! :)

Thank you for blessing people according to faith, and not holding back! I am in agreement with you, I loved this tutorial, and it was also a blessing to me.

ibadullah safdar (author)2015-01-03

Very detailed information.


Ibadullah Safdar

ChrisO3 (author)2014-10-31

Thank you so much for this great instructable. I was looking for a cheap way to thin it out to create less bubbles and this is great! I made a colour test video using different mediums to colour resin for casting if anyone is interested.

Rossana67 (author)2014-05-12

I read that aquarium rtv is food save. If I use this silicone, can I make molds for cake decorations?

JestGold (author)2013-12-07

Will be trying this to cast some 5" square tiles in hydraulic cement. From what I've been reading in the comments in Mikey 77's great post, using naphtha thins the oogoo and does not give off odors once cured, as compared to using mineral spirits or paint thinner (evidently these continue to stink well after the oogoo is cured).

I think I will try thinning the silicone with the naphtha before adding the corn starch. If anyone has done this, I'd love to hear about your results. But I will try for myself.

Thanks for a great post, and video, which really helps to see what's in store for me.

waterrocketsrule (author)2013-10-31

I love it!!!!! Works great. Im using Naptha.
Thank you for sharing

MechanicalMashup (author)2013-08-23

I am thinking you need to add less cornstarch and add it last... This might sound odd but do you live in a humid environment? The more humid the less cornstarch as the cornstarch pulls water from the air to set off the silicone. If your in a humid area the there will be more water in the air thus set the silicone off early.

Experiment a little.

spider87 (author)2013-08-23

Not a single person has has the same experience? Lol

spider87 (author)2013-08-21

I don't understand what I'm doing wrong.. I tried 50/50 then a healthy portion of mineral spirits then I tried 4pts corn starch 8pts silicone. However, when I add the spirits, everything starts setting up right away instead of softening.. What's going on? I'm mixing with a knife not a power tool.. Could that be it?

thomas9666 (author)2013-08-21

Thank you so much, been looking for an easier and cheaper way to cast molds for a long time

jhante (author)2013-06-05

Very nice instructable! I work in the industry, my company makes prototypes by casting and other methods, so I was interested to see how it can be done in your kitchen!

owsamphoto (author)2013-05-07

Could I used the mold in fondant cake designs? Is it safe or food grdae

gemini1720 (author)2013-01-08

check out the link for food safe mold making for cake decorating mold making

dlrlt530 (author)2012-12-30

Does anyone have a silicone recipe that IS safe for food and can be put in the oven, safe up to 500 degrees? Or is there such a product already out on the market? I need it in liquid form, so I can make my own mold.

binkibow (author)2012-08-18

Hi I'm in the UK & cant find 'Silicone calking' any idea what else it may be called here ?? I have been asking & retailers look at me blankly.


gatinhoxande (author)binkibow2012-10-04

the silicone calking it´s the silicone in the tues using for bathrooms, fish tanks , seel window gaps, in portugal we can get it in drog stores, i think that in ingland is the same

Marie Dailly (author)binkibow2012-09-02

Silcon sealant is the same, or bath seal. You can get it in any diy store

Did a little research and they should not be giving you blanks stares...

Maybe try asking for bathtub sealant. Sorry that's the best I can offer.

MrRetardo (author)2012-09-02

I've used Silicone Caulking to make molds before. For thicker molds, mix in some Glycerin. It helps the silicone cure in thicker layers, as silicone caulk cures by reacting with moisture in the air.. For a release agent (keeps silicone from sticking), try using a silicone-based spray such as Armor-All.

svaillancourt (author)2012-08-01

Hi, I am in need of molds for my project (it will be on instructable once I manage to finish it). I need a mold that has a minimal shrinkage. (IE 1% max). I am going to try the glycerine (I found a bottle at my local drugstore). I was wondering if I could add talc instead or starch? Anyway I think that 10:1 by weight for the silicone glycerine mix would work ok. I'll try and give you news.

Corn starch only it's hydrophilic. This is what sets the silicone off faster. Talc will not do that. Glycerin will also help set the silicone off and thin it but I have not experimented much with it. So make a couple batches and then after a week measure shrinkage.

I have failled miserably. Going to wait and buy the smooth-on kits ;)

halo99 (author)2011-01-13

Would this also be safe to use with food molds? (jello) would it be eatable?

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