Introduction: Make Your Own Silicone Molds

Using simple supplies, you can make your own silicone molding putty.

Step 1: Watch the Short Video Tutorial Here!

Step 2: You'll Need

Cornstarch

100% Silicone

Baby oil

Americana Acrylic Paints

Mixing bowl

Objects to cast

2-part plastic or air dry clay

Step 3: Make the Putty

Squeeze out enough silicone to cover your object

Add in about 1/2 the amount of cornstarch

Add a small dab of Americana Acrylic Paint

Add in several drops of baby oil

Mix thoroughly with a small spoon or stick

*Cover your hands in cornstarch and knead

Step 4: Make a Mold

Roll the putty into a ball

Press in your item making sure it covers all the details

Let cure for about 20 minutes

Remove the object

Fill with 2 part plastics, Sculpey or air dry clay

Step 5: A Few Items I Made

Comments

author
Cancunpat (author)2017-03-27

I want to make soap can I use this

author
Mark Montano (author)Cancunpat2017-03-27

Yup!

author
Ginette Périard (author)2016-11-14

I want to make silicone molds to make fondant forms for decorating cakes. Do you have a recipes for food products?

author

For food products you really need platinum silicone putty - its the only one that's food and skin safe.
Other silicones release strong acetic acid, or use tin - and these are no good.

This sort of thing:
https://m.youtube.com/watch?v=oxeRKWDWT0c

If it's for something that's a one-off, you could use something called alginate. It's very cheap, but only good for one go really - used to make body casts and dental casts. Check its not minty before buying.

author

I don't.

author
JKasun17 (author)2016-10-06

Good Morning, Mark!

I am currently attempting to make a synthetic skin for an animatronic stingray. The cast needs to be flexible to allow for wing movement.

I was thinking about using silicone molding and urethane/latex casting. I know that in your video you state that plastics are best to use with the silicone mold. Do you think that I would be able to produce a functional, flexible cast using the silicone mold?

author
Mark Montano (author)JKasun172016-10-06

It sounds like you can. The good thing is that it's not very expensive to make these molds so you're not out a ton of money either way. Good luck and let me know how it goes.

author
BirgitJansen (author)2015-05-26

Super cool! Does the acrylic paint serve any specific purpose or is it just to add some color? Love this instruct able! :-)

author

I like it because I can easily see the details in the mold when I pour. When it's white sometimes you can't see the bubbles.

author
bpark1000 (author)Mark Montano2015-06-01

I maintain that the acrylic paint has a chemical purpose. Silicone needs moisture to cure, which, ordinarily, must diffuse in from the outside. So, ordinarily, silicone caulk is useless for molding, as the sections are too thick to cure the interior. The acrylic paint contains water, which you are mixing throughout to enable cure.

author
JohnR502 (author)bpark10002016-09-08

You are correct about the paint serving a purpose... You can swap out the paint for Glycerin. You can find Glycerin at Walmart or any pharmacy. Its a clear plastic squeeze bottle.... Just a couple drops of it will cure silicone without a doubt. Just dont add to much as it will cure faster the more you add... a couple drops to 1/4 cup of silicone is what i use. Also if you want the color still you can just add a couple drops of food coloring along with your Glycerin.

author
pecker (author)Mark Montano2015-05-31

Hi, just wondering if the mould ends up
rigid or flexible

author
Mark Montano (author)pecker2015-05-31

Definitely flexible.

author
danzo321 (author)pecker2015-05-31

flexible!

author
Mark Montano (author)pecker2015-05-31

I've had some for a couple of months and they're still flexible.

author
HandstandH (author)2016-07-22

Can I use olive oil instead of baby oil

author
diggerevans (author)2016-06-27

would this type of mould be okay to use for making plaster casts?

author
Mark Montano (author)diggerevans2016-06-27

Yes.

author
diggerevans (author)Mark Montano2016-06-28

thank you mark

author
LewisB18 (author)2016-04-27

Can you put this mold in the oven?

author
Mark Montano (author)LewisB182016-04-27

No, I wouldn't use it in the oven or for food.

author
Mark Montano (author)2016-04-23

I think that would be fine Jasmin!

author
JasminBrodribb (author)2016-04-23

would you use this to cover other molds to make replicas? For example - you have a mold that is a chocolate mold but you don't want to spend $15 to get another.

author

I don't think this particular project is food grade.

author

sorry, I didn't explain it correctly. Currently I do chocolate molds, fondant etc. I have recently found polymer clay and want to do clay molding but I don't want to spend heaps of money getting duplicates. Can I use your silicone putty to cover the backs of other molds so I can have replicas for my clay projects?

author
cprphoto (author)2016-03-29

Can you do more step by step instructions with photos and materials? Thanks.

author
ltolmay johnston (author)2016-03-13

can you use these molds for fondant. the silicone molds I use for my fondant cakes is very costly to buy. and I have no idea where to buy food grade silicone in South Africa. Johannesburg.

author

Do they have amazon.com in SA? I buy most of my food molds from them. Best of luck! Mark

author
NoynonMayta (author)2015-09-20

i can do it :D

thx

author
afridave (author)2015-08-21

would the mold stand up to the heat of molten lead?...

author
jchantler (author)2015-06-15

Hello - I have a fantastic Darth Vadar Costume with ONE marvelous hard plastic boot. Any suggestions for a way to use that to create another one? I can do paper maiche, but I'd prefer something more high tech and glossy.

author
jhutchison (author)2015-06-05

This is amazing! if you swapped the baby oil for an edible oil you could use this for moulding chocolate!!!!

author

I was thinking about this myself, but besides the Baby Oil, there is also the Acrylic Paint and the Silicone Glue.

Suzanne in Orting, WA

author

Your right. The paint would need to be omitted but aquarium grade silicon is food safe as far as I'm aware. :-D

author
mkambas (author)jhutchison2015-06-15

FOOD SAFE

depends on the brand really. DAP All-Purpose Adhesive Sealant, for example, is described as safe for food contact, MW & dishwasher use (see MSDS here).

EDIBLE OIL

i'd opt for coconut oil because it doesn't go rancid easily due to its high sat fat content.

author
mkambas (author)mkambas2015-06-15

oops! hyperlinks don't show when posted? here they are in long hand:

http://www.dap.com/docs/tech/00000688001.pdf

https://en.wikipedia.org/wiki/Coconut_oil

author
BarbraM (author)2015-06-05

Can these be used in the oven? I'm wanting to make molded crayons with my students :)

author
Mark Montano (author)BarbraM2015-06-05

Not sure about that actually. If you give it a try, please let me know if it works.

author
mkambas (author)Mark Montano2015-06-15

I left my cigar on it for 5 minutes. no damage at all.

author

The easiest way I've tried is to break the crayons into pieces and place them into the wells of a mini-muffin pan. Place into a warm oven and check on them as they melt.

Suzanne in Orting, WA

author
AtomSoft (author)2015-06-05

Cool project, im jJust wondering... why doesnt the FACE mold match the item made? They are 2 different deisgns.

author
Mark Montano (author)AtomSoft2015-06-05

Actually, they aren't. I just didn't fill the mold up entirely. Only about 1/3 of the way up.

author
AtomSoft (author)Mark Montano2015-06-05

Ah ok, that explains it :) Cool Thanks

author
cburg (author)2015-06-04

This is a great tutorial. You talk about using 2 part plastic from Smooth-On but their site has a lot of different stuff on it. Could you give me more detail on just what you are using. Would that work for say casting Lego parts?

Thanks, and again good Job

author
Mark Montano (author)cburg2015-06-04

I think it would work for casting lego parts. There are different kinds of 2 part plastics. I like the white: http://www.amazon.com/Smooth--Smooth-Cast-Liquid-Plastic-Compound/dp/B004BN7G0E/ref=sr_1_2?ie=UTF8&qid=1433430871&sr=8-2&keywords=smooth+on

author
Simran Sharma (author)2015-06-04

nice

author
dawn.perry.7547 (author)2015-06-04

Thanks for this - I am looking forward to making stuff! :)

author
Wazzupdoc (author)2015-06-01

Would the mold stand up to hot wax poured into to it for making lost-wax positives for metal casting?

author
Mark Montano (author)Wazzupdoc2015-06-03

Absolutely

author
DanielaR1 (author)2015-06-02

Great!

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