Materials What do I need to cast my own BJDs

Well. that is sort of a very big question...
The short answer is: "Well , it depends".
Before you can even start to calculate cost I think you need to start with deciding on size of doll, number of parts and learn a little bit about moldmaking and casting, so that you can decide on what type of molds you need and what your casting process will be like.
Another thing to consider is how good results you need to feel it's good enough for you.

For example, small parts can sometimes be made quite well without preassure pot or vaccum chambre, if you are good at moldmaking and ok with the occational bubble. Larger parts will make that harder to pull off.

 

Not to promote my own thread too much or anything :P but check the pictures here: /threads/what-is-a-realistic-result-for-home-casting.806487/ I posted lots of pictures of my head-casting misadventures (without equipment), and other people shared their (far more successful) experiences as well. The broken links should still show up if you click on them.

You can cast a decent number of heads with one resin kit, but if you end up having to redo things because your casts are full of bubbles (as mine were), then you're going to waste most of it.

If you:

• don't mind bubbly casts
• don't mind if your bubbly dolls cannot be declared on-topic here because of the casting quality, and
• just want to learn about resin casting/think the process could be fun

...then go ahead and give it a shot But don't go into it expecting to save tons of money over getting your doll professionally cast. Maybe you will, but it's very possible that you won't.

 

There are a lot of options to smooth on out there as well.
They have been marketing their products pretty hard the last couple of years, but there are many lesser known companies that sell very good products, often at lesser cost. If you are ok with less pretty packaging and less cutesy names, check out whats avalable locally to you.

It still will be expensive, though. Not only do you need the materials for your project, but you need to test out different materials to find what works best for you. I can't stress the importance of testing your materials enough!
For example, the resin I use don,t need a preassure pot, as long as humidity is low and the mold is well constructed with vents for the air to escape in the right places, but the silicone does get bubbles. For small parts it's usually fine, but for large parts, the heat produced by the resin as it cures causes the bubbles to expand and gives the charachteristic "poc marks" in the final cast. Others have experienced the opposite, where the silicone is fine and cures without bubbles, but the resin foam up, or cure too fast and trap bubbles inside. (There are tricks and workarounds, but they are often unique to the piece cast, so it's not much use listing them without context.)
Simple variations such as what pigments, how much pigment and what type of mold release also afects this, so all the things you use need to be tested toghether. And enviromental variations such as temperature, humidity and drafts also matter, so simply reading about other peoples experiences -though helpful- isn't enough on it's own.
The testing process is one of those things that often seem tedious and wasteful when you are new, but the more you do this, the bigger a fan of tests you will be.

To make testing more fun you can always make a small part, such as a hand, foot or accessorie (I make tiny coffe mugs) to use for testing. That way you still have something to show for the materials "wasted" on tests.

The one post that will likely be the most expensive all at once is the silicone. That's the reason for the minimum order number for custom cast dolls, you need to spread the cost of the mold making out a bit to make it viable economically.