Instructables
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.

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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.

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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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Not liking the $20 - $60 price tags on silicone molds I just tried this! Cost me about $4.69 to make two and they seem to be just as good as the one I bought recently! Thanks!

tried today, used white silicon and some cheap morrisons red wash liquid as had no blue, worked a treat my only mistake was adding it all at once , by the time i got to the last of my mould items the silicon had started to set so it wouldn't work, def my error, next time i will only use half at a time, , i used a plastic bowl, cold water and a good squeeze of wash liquid, thank you for the great tip, will have lots of bespoke buttons now :)

audreyobscura (author)  mysterymayhem21 days ago

bespoke all the things! Post pictures of your castings?

TheVClique1 month ago

This sounds great! Do you think I can use DAP Clear 100% silicone sealant?

http://www.homedepot.com/p/DAP-10-1-oz-Clear-100-Silicone-Sealant-2-Pack-207559/203661695

I tried this yesterday around 8pm, and the mold is still squishy! I was wondering why this may have happened. It's been sitting for about 17 hours and it's still just as squishy as it has been. Did I not use enough soap? Did I not knead the silicone enough? Please help. Thank you! =)

lakisok2 months ago

I am trying to recreate a hand mold made in my patio concrete from my children's hands and our then dog's paw prints. The impression is in the pressed and colored material. We are moving to a new house and I want to preserve their prints for posterity. I think I may need 2 ft square more or less how would I apply it? and my idea is to then pour plaster of paris (spelling) over mold to recreate the original impression.... then air brush paint a patina. so Qs are:

1. how much silicone is needed? And how do I apply

2. what do you suggest I use and by what method should I apply the plaster

I would try a product like an air dry clay to reproduce your hand and paw prints. You can pat the material over the images you want to keep, peel it off carefully & let it dry thoroughly. Then you can either use more air dry clay and make the positive impression with it or go through the whole mold making, plaster casting routine to make your memento. Or buy a kit at one of the craft stores to make your mold. I used air dry clay to preserve some family signatures that were put into the wet cement of the house my husband's grandfather built. The house had to be sold and his sister wanted the signatures preserved. I never got around to making the reverse impression from the air dried clay.

I've seen this method somewhere but with a different appliance technique. Though I can find anywhere if this type of Silicone mold will be good to try and make smooth clear plastic casts, do you know if it will? I saw some youtube video trying to say Platinum cured silicon is pretty much the only one for that...

audreyobscura (author)  CiprianoHernan1 month ago

That would definitely be the case - this method is a bit rough, but still great for quick and dirty casting.

Thanks for the reply! It's been a while since I actually had someone answer me when I ask about things like this. Anyway, I was hoping this method could atleast even be capable of smooth surfaces due to the smooth-on molding material are far too expensive just to try and mold small parts.

I guess I'll have to deal with it though if I want my result to come out any kinda of professional quality. Thank you for your time!

SparkySolar made it!1 month ago

working on making spec soap requests

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stinebusch2 months ago

This is amazing! I can't wait to try it out. I have some questions, maybe someone knows the answers?

How did you make it a complete figure? Cast the other half and then glue? Can you cover it in two halves of silicone? What's a good way to do this?

Can you cast any material, like plaster, fine sement or molten plastic in this?

Is it a good idea to use a bit of Vaseline on the casting object to make it easier to detach or is this simple anyway with silicone?

Cheeeers!

pocholox82 months ago
I am definitely getting a dinosaur just to name it Jesus, damn isn't that the smartest name! you totally changed the way I make casts thank you jesus!
Cube_4 months ago

This doesn't seem feasible for larger projects, how dissapointing. (I'm make various custom things and decided I want to make two custom electric guitars for myself, one out of wood and another out of either fiberglass and resin or carbon fiber and resin (with a custom airbrushed paintjob) and a silicon mold seems the best option for this (since the resin one will be the same design as the wooden one)(
Any suggestions for how to make a silicone mold for large objects?

equal parts cornstarch and silicone using baby oil to mix it well into a paste them spread it over your item that you want to mold. it cures quickly so work fast

audreyobscura (author)  Cube_4 months ago
Hey there! I have used this technique to cast larger objects....sort of.

My methodology is to make cardboard, or coroplast negative molds, and then coat them with silicone. The Silicone doesn't machine all that well, but I have found that cake decorating tools are the best for spreading it, and making even layers.

Cheers!
Audrey

that's really not feasible for my projects, I was hoping I could just build a square of wood and put the object in it and pour silicone over it (once it solidifies I could just flip it over and pry the object out)
My workflow will require the additional structural integrity to make sure the mold doesn't deform too much while I apply carbon fiber and resin (causes air bubbles and looks bad, sometimes it cracks altogether)
Further I'd prefer if the mold was re-usable

Any idea how I could achieve this? I tried googling it but apparently most people don't cast very large objects

The Rambler Cube_3 months ago

If you look into costume and prop making I think you'll find some pretty decent sized items being cast. The silicone of choice tends to be a Smooth-On product. I haven't personally used it, as it is a bit expensive to just play around with and I haven't needed it for anything that justified the expense, but everyone who uses it swears by it.

Cube_ The Rambler3 months ago

Oh? This seems to be what I need actually
"Project Specific - Smooth-On's wide range includes mold rubbers that can be poured on , brushed on , sprayed on or pressed on to any original sculpture and will reproduce detail perfectly. Reproductions can be cast in urethane plastic, epoxy resin, plaster, concrete, and more."
thanks ^^

The Rambler Cube_3 months ago

No problem.

Polinom1002 months ago

Can you cast metal in this silicon mold?

audreyobscura (author)  Polinom1002 months ago

I've never tried! Maybe low melting point metals like pewter

dalucero3 months ago

So just to be clear, the soap only speeds up the curing right? It's not required?

KzooK1 dalucero3 months ago

dalucero,

I'm not sure if the soap affects the curing, but it keeps the silicone from sticking to your hands and the mixing bowl by forming a release layer between you and the silicone. It doesn't have to be expensive soap; any clear (not creamy-looking) hand or dish soap from a discount dollar store would work ok.

kbeagle3 months ago

I would like to make a mold out of real strawberries to use in my soap making. I was in hopes to be able to put the silicone into something like a shoe box or smaller with about 10 strawberries, maybe 12. What would you suggest? Thanks!

VenialVenom5 months ago

Hi :) I love this instructable. I was wondering if you might know if this method of mold making would be safe to use with cooking. I would like to make some fondant molds but not sure if it is safe to put food stuff on this silicone. Thanks for sharing this project :)

Just passing along information. Be sure to check for food safe ratings! Interestingly enough many aquarium 100% silicone sealants are food safe (again, just keep an eye out for the rating). Aside from that most of the food grade sealants I have found can withstand 400F when fully cured!

example product, not favoring: http://www.amazon.com/Clear-Food-Grade-Silicone-Sealant/dp/B005XP5HO6

audreyobscura (author)  VenialVenom5 months ago

DEFINITELY NOT! I think there is food safe silicone, if you need it.

bgbdbill674 months ago

I will be testing this out tomorrow with this product on a candy mold. It lists on the package that it can come in contact with food. http://t.homedepot.com/p/DAP-2-8-oz-Silicone-Aquarium-Sealant-00688/100128841/

SaintAstra6 months ago

So I tried this and finally succeeded - right silicone, dish soap. The mold came out nice (any imperfections were my own fault) and it even dried within a few hours. I made two molds. I poured my resin and when I popped the piece out, it was eaten away and tacky, like the surface of the moon only a lot grosser. It wasn't cured all the way and the parts that had touched silicone felt like melted gummy bears. It reeked of vinegar (No idea why, since vinegar went nowhere near this project). The inside of the mold had resin residue, all tacky.

I waited a full day, washed the second mold out thoroughly, thinking maybe the dish soap reacted or it was a bad batch of resin. Nope - tried it again, this time put half in the silicone mold and half in another plastic mold for control. Resin cured fine in the plastic but was still eaten away and tacky in the silicone mold. Not just in the cavity - I put a drop on the flat part of the mold, and that won't even come off it's so tacky. I have absolutely no clue why this happened.

I used:
GE Silicone I 100% Silicone for the caulk (tried it with II and it was a noxious failure)
Dawn dish soap
Wilton Liquid Glycerin
EasyCast Epoxy Resin
Tap Water

I use resin to make jewelry, and it sounds to me like you need to try a new resin. It doesn't sound like the resin is setting right, which has nothing to do with the mold. I would try a different resin mix. Could it be there is something wrong with your product- too old, not mixed right by the company? Good luck in the future.

I just tried this method and it is super easy! Thanks so much. I used Dap 100% silicone. It has a very low odor that I am sure will dissipate over time. This method is going to save me a ton of money and much search time.

ukiran15 months ago

hey I am from India, has anyone tried from this part of the world, if so can any one let what ingredients (make of silicone) and can you let me know where i can find resin?

Thanks

jsrubianoch8 months ago

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

jerrycwood8 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?

tubaska9 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)  tubaska8 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
kpsmree9 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)  kpsmree8 months ago

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

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