It has several qualities that make it suitable for amateur experimenters: it's not poisonous, it has a fairly low melting point, it's cheap, and it has a really lovely crystalline structure. It's great fun to play with.
I got the health question a lot from people I mentioned this project to. Unlike lead, mercury, nickel, or other metals, there is no significant health risk from vapors or from touching bismuth or ingesting small amounts (it's actually the active ingredient in a popular brand of stomach medicine). There is of course a burn risk when you melt it, but adequate precautions and basic care reduce this to levels that are quite acceptable for me - it's really no riskier than boiling a large pot of water.
Step 1: Equipment and Safety
As with nearly anything these days, bismuth can be purchased on the Internet. I got a pound for about $15 US. This turned out to be a cube (more or less) of an inch and a half to two inches on each side.
Obtain the following additional items:
- goggles in case of splashing
- leather gloves
- crucible - stainless steel pot or bowl
- heat source - stovetop works fine, i used a camping stove
- big tweezers to pick out crystals
- pliers to handle crucible if it has no handle
I got my bismuth from Rotometals for $15 plus about $7.50 shipping, which was lowest for my location. Other online sources sell it as well.
Step 2: Melting
Step 3: Crystals
The iridescent colors are caused by oxidation, which happens very quickly when the melted bismuth is exposed to air. It may be possible to reduce this by plunging the crystal immediately into water, but I did not think to try this - next time!
Step 4: Pouring Into Water
The picture shows the results. Notice there is no oxidation!
Step 5: Pouring Into Molds
We also poured some and attempted to insert pins to make pushpins. This did not work so well - the plastic one melted and the nail is loose. It was moved slightly before the bismuth was quite solidified -- and the bismuth doesn't stick to steel.
Step 6: What Else?
I sanded the back of one of the crystals that was particularly beautiful. I will epoxy a loop onto it so it can be worn as a pendant. What with the non-stickiness of the bismuth I'm not sure epoxy will bond to it but I'll update this when I find out.
One thing I noticed was that the bismuth did not bond to things very strongly. It got all over the ends of the tweezers but I was able to crack most of it off once it had cooled down. It splattered a bit over our metal table but didn't stick to that either. It didn't stick to the silicone mold at all (of course this is also a property of silicone). It didn't stick to the nail. I was able to crack some of it out of the mixing bowl, although not all. The bismuth particles on the sandpaper fell right off too, unlike most things which tend to stick to the grit, and can only sometimes be brushed or tapped off.