Casting part 2
In Part 1 we went over how to create a mold. Now that is done we can start to create cast resin copies.
Things you'll need
- Disposable cup
- Something to stir with
- Measuring cup
- Something to wipe up messes with
- Syringe (mine's a turkey injector with the needle removed)
- Old paint brush
- Xacto blade
- Casting Resin (I'm using Smooth-On Task 4)
- Patience, and lots of it
Mixing the resin
Compared to creating the mold, mixing the resin is pretty easy. Both Alumilite products and Smooth-On are a 1:1 mix ratio. So you use exactly the same amount of both Part A and Part B. I'm using Task 4 because it was recommended by nova especially for really small details, like say a miniature USS Flagg Monopoly game piece.
For this product it says to make sure Part B is stirred thoroughly before mixing in Part A. So start with Part B first. Use your measuring cup to measure out the Part B. Stir it (gently so as to not create bubbles) and pour it into the cup. Now measure out the Part A and then stir them both together, again gently. It has a 20 minute pot life, meaning working time, so you can take your time, however, it does mean you should have a block of time set aside just for casting. I can't tell you the number of times something has come up that needed my attention right after I mixed the resin.
Use the syringe to suck up the resin from the cup. You are not going to to want to put a lot of pressure on the syringe plunger. A slight bit of pressure, like moving the plunger 1/8 of an inch, is all you want. Let flow into the mold. Then add a little more. Squish the mold and even use a coffee stirrer to make sure the resin is getting everywhere you need it to. Add a little more resin. If you created multiple mold, inject the resin into those using the same method. Slow and steady.
Similar to when the mold was created, I tap the mold on a table with the resin in it to get any bubbles out.
This Smooth-On resin takes 16 hours to cure thoroughly. Usually I wait about 8 before taking it out of the mold so it has a little give to it. That's a personal preference thing.
You want to spread the opening slowly. usually one side will come off easier then the other. You might have to work it around a little. Use the knuckles on your index fingers to push up from the bottom while you spread the opening wider with your thumbs, almost like your kneading into it. Once you've got the sides free you can reach in and pry the piece out. Again be slow and careful. The last thing you want to rip the mold by being too rough. Once the piece is out, let it cure out in the open over night. Once it is completely cured you can trim off any access resin.
Even with the best prepping and taking things slow and cautious, you'll still get the occasional air bubbles. It isn't a lost cause though. You can use an old paint brush and some 15 minute old resin mix (just when it is getting a little tacky and thicker) to fill in the gaps or even do a minor repair of something broke off. If it isn't starting to thicken yet, don't bother. The resin will just drip all over the place.
Oh look a fleet of Flaggs and a bunch of other cast pieces.