I've got a few years' experience pouring bismuth/tin and powder painting as well as vinyl painting and have put together text and photos in response to hamma's recent post that may be helpful.
Hamma is wise to consider gearing up for safety before plugging in the melting pot. Let's look at some gear:
Goggles or a full face shield should be worn. A 3M respirator with organic vapor cartridges is a must if you've got time and patience for vinyl painting and is worth the slight discomfort to wear while molding. Dress in shoes or boots, jeans and a heavy, long sleeve shirt with the cuffs over your gloves. You don't want a casual attitude about safety. Pay attention!
Here are the tools of the trade. I used a Palmer Hot Pot 2 for years and never really felt comfortable with it. Even half full, it's a fair amount of weight in the hand. It's also possible to carelessly catch the cord and dump the contents of the pot or - carelessly again, to be inattentive while setting it back on the small trivet and tip it . . . Spend the extra $15.00 and get a Lee Pro Pot IV.
I'll tell you a story now about my first pour with Rotometals' 281 alloy (58% bismuth/42% tin). I opened the mold as soon as the shine went off the sprue and admired the perfect casting for several seconds. Then I put pliers to the shank of the hook and pulled. And pulled, pulled and yanked! I swiveled around in my chair half expecting to see Rod Serling grinning at me. See, what I didn't know was that bismuth is one of a very few metals found on our planet that expands as it cools. Not long after this experience I learned that a liberal coating of Frankford Arsenal's Drop Out silicone spray makes removal of your just-poured jig easy. You still want to work quickly, however. And removal from some molds is easier than others.
See the instruction pamphlets for the melter and the molds? When you read them you'll know what the screwdriver does, what the oil is for and all sorts of other stuff that will make this hobby safe and simple. Dull as it may be - and I'm going to raise my voice here - READ THE INSTRUCTIONS!
You've plugged in the pot and turned on the fan, your basic box fan surrounded by insulation foam. You can see the smoke from a snuffed out match or candle go out the window. This is adequate ventilation.
Adding an ingot to any amount of molten metal is nothing to be in a hurry about. Same goes for when you're dropping nipped-off sprues back into the pot. Use a spoon to do this.
See the slot in the top of the valve rod? Turn the rod a few degrees left and right to "resettle" it to stop any dripping. Oh, you already knew that because you've read the instructions. Okay.
You see the mold fully loaded but I actually prefer to cast one or two at a time. I put a number of jigs into the pan on my left. The nippers work great on the bismuth/tin (which is brittle, unlike lead). The other cutters are used for soft lead.
It's up to you if you want to file. It won't make a difference to the fish. I do, and the filings of alloys that cost $15.00 - $20.00/lb. fall into the cookie sheet below the vise then go back into the pot.
Since I read how well teflon pins work, I never bothered to try the pins supplied with the mold. Remove them with pliers rather than risking impaling a finger tip. Ah, I'm boring you now because you saw this in the instructions which you have studied.
See the little bit of flashing on the barbs? After you've pulled the jig from the mold, check to see that these specks are not sitting on a flat area. Flick all off so you can close the mold properly for the next pour.
Satisfactory results are not hard to obtain with a reasonable amount of practice, patience and focus. I can't stress strongly enough the importance of working in a quiet environment, taking your time, and understanding the characteristics of the materials you're using and the tools at hand. Work safely and enjoy the hobby.
Let's go now to powder painting and curing.
I'm reposting the article about my first experiment with powder on 58% bismuth/42% tin alloy.
I was better tooled up for my second trial in
I stated at the end of this article that "the larger 88% bismuth/12% tin jigs are very difficult to remove from a hot mold." Let me clarify that by saying jigs poured in a 1/4 oz. Poison Tail mold can be removed until the mold heats up - and this hardly makes for an efficient production run. Do-it's Herring Head Jig, on the other hand, is not a problem.
A few weeks from now I'll be molding and powder painting pewter, an alloy of 92% tin/7.75% antimony/.25% copper, which weighs only 2/3 as much as lead but can take the heat required to fully cure powder. I'll report the results.
