Make a silicone mold from common household materials in your kitchen in 1 hour

Taking off from this BRILLIANT 'ible http://www.instructables.com/id/How-To-Make-Your-Own-Sugru-Substitute/ 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

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

Comments

[owsamphoto]

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

[gemini1720]

http://www.makeyourownmolds.com/how-to-make-molds

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

[dlrlt530]

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]

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.

Cheers

[gatinhoxande]

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]

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

[MechanicalMashup]

Did a little research and they should not be giving you blanks stares...
http://www.google.ca/search?hl=en&safe=images&client=safari&sa=X&ei=5qYvULHtPKOKjAKC3oCwCg&ved=0CFcQvwUoAQ&q=silicone+caulking+in+the+uk&spell=1&biw=320&bih=417

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

[MrRetardo]

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]

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.

[MechanicalMashup]

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.

[svaillancourt]

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

[neodymium]

Could I use a non-alcohol thinner like turpatinen or a low alhol content thinglike 70% rubbing alcohol? What would happen to the mix if I didn't add any at all, because it sounds like it would shring less without any thinner? Thanks.

[Anyakin]

This is why I love Instructables :)

[kommodore]

Dude!!!!!!! i just try this and it turned out excellent!!!!!! thanks for this great instructable!! i was wanting to make some silicone mold for a long time, and i didnt wanted to spend like 40 dollars on 1 kg of two part rubber silicone, so you save me a lot of money, i mixed silicone and corn starch on 1:1 ratio, and then add paint thinner, the mold turns out really well, alltough, next time i will use some more paint thinner so the mix gets more runny.

So thank you!!

[mschell1]

if you dont add the mineral spirits, does the mold still shrink?

[MechanicalMashup]

With no mineral spirits the mold will stink but very very little compared to a mix with mineral spirits. With glycerin it will stink but more than no additive and less than mineral spirits...

[cathypeek]

I bought odorless mineral spirits in the art section in Michaels. It's by the brushes, oils, canvases, etc. I don't think I added enough and my mold is lumpy but it got the job done. Ugly as all get out tho.

[MechanicalMashup]

Glycerine does not thin as well as mineral spirits but definately does not smell nearly as bad. Remember that when the silicone kicks it will smell very strongly if vinegar or acetic acid...

[cathypeek]

I want to make triangle shape crayons from melting old wax crayons. Is it possible to pour hot crayon wax into this type of mold?

[offtherails2010]

Also im going to be making a shed-load of molds for pouring casting-resin into (potting) and the resin cures by a chemical reaction causing the tepmerature to rise to about 60°c (140°F) and will be using a silicone caulk thats rated to be temperature resistant to upto 300°c (572°F !!!) !

The one i bought is called 'Heat Mate' in the UK (bought from my fav specialist shop, ebay, lol !)

Plus im going to be using this heat-resistant silicone to make some RC Buggy Parts that are located next to the engine so that it can better protect against a very high heat source !!!

Hope that helps !

[cathypeek]

Thanks offtherail2010! I appreciate the Heat Mate silicone caulk tip. I have made a mold--you should see it...pitiful but it's a triangle-shaped mold. I took leftover crayons home from school to melt and those crazy things would NOT melt! Oven at 300 degree F. They must have plastic in them rather than wax. Need to buy the old crayola brand and I bet they would melt. This is my goal over the summer. Have a great week!

[offtherails2010]

Your most-welcome cathypeek !!

Always happy to help !

lol @ pitiful !

As long as your mold serves its purpose i always say it doesnt need to win any beauty-contests as long as it does what you need it to do lol x 2!

Also with repetition you will get much better at creating molds as after the 1st one its all a learning curve & the good ol' trial & error methods !

Just slightly curious thought, is there a specific purpose for having triangular crayons ?!?

[MechanicalMashup]

Yes it is... The temp of the crayons melted is fine with these molds

[cathypeek]

Thanks for your reply. Realized I needed a 3D triangle shape so I purchased sculptey clay to make it. I am going to try making a mold but need to watch the video again. I'll let you know how it goes. Thanks again!

[offtherails2010]

*** !!! DUDE !!! ***

I'm back to finally test out your GREAT instructable !!!

i just have a question whilst i wait delivery of some Play dough !

Instead of using mineral spirits, would you think it'll be a good idea to use 99.9% Isopropanol as its the closest thing i have to any kind of spirits ??!!!??

[grunt1612]

hey guys if you guys need silicone RTV contact this guy its pritty cheep [e-mail]

[Lonecoon]

You can also use Glycerine to produce a mold that won't shrink, as glycerin adds the necessary moisture content to the mold.

[MechanicalMashup]

Ill have to give that a try. Where can you buy glycerin? I assume a pharmacy will have it?

[mschell1]

have you given this a try? i am about to go out to the store to get the materials for this project and i need to know what i should be getting, the mineral spirits or the glycerin?

[Lonecoon]

It will be in the laxative section, or in the beauty supplies. You can get the in droppers. You need about 3 drops per ounce of silicone.

[cakeladyd]

Hi, I am very interested with this technique, is it food safe? Could I use Sugar Paste and it not be harmful to the cake? thanks

[MechanicalMashup]

No its not safe for food. Using solvents in the silicone and the silicone itself will leach into the food and essentially poison it.

[cakeladyd]

thanks for the update, very helpful, guess I am back at the drawing board or just spending the money to get the regular stuff. thanks have a great day

[Batness]

You can buy basic supplies from a lot of retailers cheaper than the "regular" stuff...it's a good "in-between" compromise.
http://www.makeyourownmolds.com/how-to-make-molds

[just pick a name]

To deal with the shrinkage problem, you might try just painting on a thin layer of this thin mix for a detail skin and back-filling with regular oogoo after it sets up. Since silicone sticks to itself quite nicely, it should work. The only thing I wonder is if the skin's higher shrinkage would tend to warp the mold. My guess is that if it's thin enough, it will be held stretched by the regular oogoo.

[swankaliau]

Hi i need some help for making a big mold for faux stone .Could u pls tell me the ratio of silicone calking that you've used in the mix? And could the mold handle wet mortar on its surface?RTV is sooo expensive and this is a great idea for my students building project. studentsbuildingprojects.blogspot.com

[MechanicalMashup]

Oh and wet mortar will not be a problem

[MechanicalMashup]

I really did not measure it was just a by eye and feel thing. One thing to keep in mind is that the more thinner you use the more shrinkage you will have in the mold.

[EngineerJakit]

think this could be used for making plastic injection molding stuff? Im trying to make some merchandise for a person I know. She has a pretty successful webcomic site and Ive been having trouble trying to make some molds.

[MechanicalMashup]

I think plastic injection is a bit much. This is more a press mold like seen with the playdough or a pour mold. Keep in mind to there is a decent amount of shrinkage in these molds...