Wiggy How-To and Restoration Guides #3: Casting Parts

So, you wanna cast your own parts?  I’ve had a ton of requests for this FAQ.  So, after a LONG hiatus, here is the latest wiggy How-To.

Materials list (some items aren’t pictured):

•  wooden mixing sticks

• Measuring cups/spoons

• mixing cups

• silicone spatulas

• foam core board/plywood/sheet plastic (plexi, styrene, etc.)

• rubber bands

• box cutter/Xacto knife

• paper towels

• isopropyl alcohol

• hot glue gun

• syringes (optional, but EXTREMELY helpful for casting small parts)

• toothpicks

• rubber/latex/nitrile/whatever gloves (this shit is messy and sticky, you’ll want these)

• mold making silicone (http://www.dickblick.com/products/easy-mold-11-rtv-silicone-rubber/?clickTracking=true)

• casting resin (http://www.dickblick.com/products/castincraft-easycast-clear-casting-epoxy/)

• mold release (http://www.dickblick.com/products/castincraft-mold-release-and-conditioner/?clickTracking=true)

• colored dyes (http://www.dickblick.com/products/castincraft-transparent-dyes/?clickTracking=true)

First figure out what you want to cast.  I’ll use various portable buttons as an example.  Here are a slew of GBA buttons that I want to use in order to make a family/gang mold (single mold that produces many like parts)

These will require a 2-part mold.  I will first attach these all to a piece of foam core board with some hot melt glue like so.

Next I need to build walls around the board so that I may pour in the silicone which is used to make the first half of the mold.

Now that I’ve done that I will mix the silicone and pour it into the chamber.  Follow the directions regarding setup time for the silicone that you’re using and then pull the walls from the cured silicone and flip it over once it’s cured.

This part isn’t necessary, but it will help keep your mold together when you start casting, not to mention helping you align it.  Cut some wedges into the sides as shown.

You’ll see why later.  Now, with the mold facing up, build walls around it one more time.

We are now going to pour the 2nd half of the mold.  Prep the first half with mold release/conditioner.  This will help you pull the two halves apart when the 2nd half is done curing (this step is important, otherwise yo may not be able to pull the halves apart without destroying them).  Mix and pour the 2nd batch of silicone on top of the first half.

If you have very small cavities that need to be filled (as I did in the buttons you see in this mold), then you may want to carefully coax some silicone into those cavities with a toothpick or syringe before pouring, otherwise silicone may not enter those cavities and you’ll end up with a mold that makes parts which are incomplete and possibly useless.

You’re set to start casting once the mold has completely cured.  Carefully pull the halves apart and pry your original part(s) from the mold.  Mix you resin as per the instructions and add whatever dyes or materials such as glitter that you want to the mixture.  Let the resin settle so that the air bubbles are all but gone.  Again, filling small cavities is important.  Use a syringe and/or toothpick to coax the resin into the small areas so you don’t end up with incomplete parts.

Fill the rest of the cavities with the resin.  You will want to run a toothpick around the inside of the cavities once the resin has been poured.  Air bubbles like to form at corners/edges inside the mold, and you can easily work them out by running the toothpick around the corners and edges.

Make sure all the little nooks and crannies are filled in both halves of the mold.  When you’re sure that you’ve got both halves ready to go, then quickly place them together and align the tabs that we made in order to secure the mold halves together.  Err on the side of too much resin versus too little.  Any excess will be squeezed from the mold.  Once you’ve go it together you’ll want to secure them with something a little more substantial.  Do NOT press the halves firmly together with your hands.  Doing so will squeeze some resin from the mold and when you release, the mold mwill decompress and draw air back in, creating bubbles and imperfections in your part(s).  Gently place the halves together, then secure them with some plywood or plastic and some rubber bands.  This will ensure the the mold is secure that you’ll have the least amount of excess resin left in the mold when all is said and done.

The resin that I provided links to requires at least 24 hours to set.  Don’t be impatient and DO wait at least that long.   Remove the rubber bands and gently pry the mold apart with your hands (don’t use any sort of hard tool as you may tear/rip the mold).   Now all you need to do is pull the casting(s) from the mold and trim the excess resin with your knife.

Presto!  You have replica parts 🙂

Bigger parts can be made and there are many different casting materials that you can use.  But that’s for another FAQ 😉

Hope this helps you ladies and gents out!