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)
Latex gloves (or what ever kind you like)
Something to cast or mold
Step 2: 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
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
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
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
Step 6: 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 http://MechanicalMashup.tv or join our facebook fan page at http://Facebook.com/MechanicalMashup