Step 6: Use your mold!

Picture of Use your mold!
We made a sparkly rendition of Jesus with clear casting resin and glitter. When the resin began to gel we set three LEDs inside of him. Behold the sparkliest light up dinosaur in West!
EddieW426 days ago

Has anyone who has tried this method also used Smooth-On Mold Star? Smooth-On is very expensive, so finding an alternate would be great. But I'm wondering how this method compares as far as work-time and flexibility of final mold. I need to make a single part mold of something with a bounding box of about a 1' cube. So I will need to make a large amount of this molding material as well as need to cut it afterwards to extract the object and make a cast. Can anyone speak to the material's ability to be made in large quantities at a time, be cut after curing, and flexibility?

Thank you in advance

soooo...i made a mold just now, it's currently curing, and the silicone was NOT fun to get off my hands! Just a warning for those who have never used it. Any tips on how to get off the silicone?

Not sure of any easy ways of removing it, maybe try acetone.. Gloves might be a good investment :P

izzyev5 months ago

soapy water is to silicone as flour is to pizza dough.

Where did you buy your l.e.d.s and your resin? How long did the l.e.ds last?

paqrat3 years ago
This is way cool. Have you tried it with the white silicone caulk?
I have. It... didn't end well. The pigment in it felt like it was burning my hands after I started pulling it out of the soapy water. I'd stick to using the clear.
Back when I had aquariums there were some folks making their own aquariums and someone said you didn't want to use some of the bathtube silicone caulk cause they have some sort of fungicide in them to prevent mold in the caulk. That may be what you felt on your hands.
jacco1997 paqrat6 months ago

Sounds like they really designed it to prevent mold! (get it? because molds)

kpsmree1 year 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

jacco1997 kpsmree6 months ago

Clay will not work for this application. If you want to slip-cast, you will need to make your negative out of plaster. Plaster is porous, which sequesters the clay's water. If you still have your positive, make a plaster mold from that. If you only have the silicone negative, cast a plaster positive and then cast a plaster negative from that.

simonsch6 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.

stinebusch1 year 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?


bgbdbill671 year 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/

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 :)

audreyobscura (author)  VenialVenom1 year ago

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

jerrycwood1 year 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?

Smalfrii1 year ago
this is perfect! thank you so much for posting this! i had already tried using this fancy mold making kit, but it failed miserably. Never cured. i can finally finish my project and post it :)
jharris672 years ago
that is AWESOME! thank you so much for this! I've been mulling whether I wanted to spend $20 to buy molding materials from Michaels.
maggiemul2 years ago
Does any1 know would you be able to use this to make a mould of your hand by adding a release agent to the hand? I need to make reusable moulds of hands?:)
audreyobscura (author)  maggiemul2 years ago
Hey, you could make a mold this way, but you dont really want mold release or silicone on your skin. I would wear a tight fitting latex or nitrile glove spritzed with some cooking oil to get a good release.
This is so awesome! Thank you so much for sharing these instructions. :)
Do you think the mold could go in the oven, like silicone baking products? I was thinking this would be awesome for making custom crayon molds.... but I don't want to kill myself with off-gassing or chemicals.... Thank you, this looks like such an awesome idea!
Silicone generally is heat safe up to about 500 degrees F (give or take). If the stuff you're using is genuinely 100% silicone, it should be fine in the oven... especially at the temperatures needed to melt crayons. Might want to open a window just to be safe. :-) Let us know how it goes!
Dark Light2 years ago
This is neat! Caulking isn't just for bathtubs anymore. lol. Thanks for posting this...I'm sure I'll get some use out of it.
maggieelrod3 years ago
I love this idea but really want to figure out how to make a very large mold ( with both sides, so it can be put together) of a large urn. Does anyone have any ides?
fjordcarver3 years ago
Mix cement or grout with silicone to make aquarium safe, textured models. You have to leach them (soak, dump, soak, dump) to make sure they don't interfere with ph balance if they are going in a water tank. For a terrarium I wouldn't bother, but let them cure well.
It is water that accelerates the curing. water in corn starch or grout. (which is why in recipes for both these agents, you start with a certain amount of water too add and then add accordingly until mixture is right, depending mainly on air humidity and how much is already absorbed)
The soap releases, which is why it works way better than spit for going around a tub(spit works too, but silicone unavoidably sticks to your fingers and makes a mess eventually)
fjordcarver3 years ago
I just found this because you tried my little app (or someone typed your name in), and because in your stats it was third most popular. I am really glad I found this. Double huzzah, because you tried my app, (another editor...triple huzzah). So thank you for both, ('ible and visit)
I can't wait to try this out. So cool. A liitle dish of water and dishsoap is great to smooth the joints when caulking around a shower or tub too.

Silicone is awesome stuff.
mediabeing3 years ago
Gee, I wish you'd shown us a standard casting so we could see if the mold really works [reproduces detail well]. Oh well. Maybe you'll do that next time. Yippeee!
killbox3 years ago
The water is actually the catalyst, the soap pretty much works as mold release.

you can also do this with pure silicone caulking and a teaspoon of corn starch, (it too will quickly catalyze the silicone.

you can then soap cover your object and your hands and make a mold you only have about 5-10 minutes to work the stuff before it becomes too thick and rubbery.
danzo3213 years ago
I know that this technique can give pretty high quality results, but here I see no t-rex teeth etc. You could lightly grease the object, squirt silicone I on it, and let it cure, and if using the clear, cut the mold with a sharp blade to free the pattern object. But you also should build a funnel in to the mold so you can get resin into it.
prahs3 years ago
I didn't see any mention of how the second half of the mold was made or registered.
I looks like it makes a pretty crude cast, although it does have the sparkle going for it.