Messing about with pewter

footfootfoot · 02-21-2017, 10:10 PM

How funny, I just made a plaster mold to pour some lead ducks for fairing boat lines. (relax, it's only a model)

I learned lost wax bronze casting and mold making in school. You can pour lead or pewter into a plaster mold, but you sort of did it backwards, Make your master positive out of something like wood or wax then make a plaster mold of your master positive. If there are no undercuts the positive should pop out once the plaster sets up. You can use your carved plaster as a positive if you seal it really well and use silicone or something as a release agent. When you've made tour plaster mold let it dry thoroughly. an hour or so in a low oven should do it. You can now pour the pewter into the plaster mold.

Another way to get a really detailed mold for one-offs is to get some dental alginate to make your mold. You can pour several wax positives with it before it dries up or falls apart. Then you can pour plaster over the wax positives, encasing them fully but allowing for a sprue and a vent, You melt the wax out of them (outside, low campfire coals be sure to add sand to the plaster to give it strength) Then while still somewhat hot you pour the metal.

xoxoxoBruce · 02-21-2017, 11:28 PM

I accidently forgot to take some Bismuth alloy out of my pocket, and brought it home. It's bad if you get fired taking something out but a damn fool if you get caught bringing something back.
This Bismuth alloy melts at 158 degrees F (yes it'll melt in hot water), we used it in tooling to locate bushings in drill fixtures where the old bushing was ripped out leaving a huge hole. It also expands slightly when it cools holding the bushing tight.

My buddy used to do a bunch of wood carving and he bought some silicone mold material so we cast several of his carvings. This one is about 3" high and has good detail. I mounted on a piece of Cocobolo scrap with some stars above and a wood chip that looks like a butte below, calling it, "Between Heaven and Earth"

glatt · 02-22-2017, 07:11 AM

Quote:

Originally Posted by footfootfoot

How funny, I just made a plaster mold to pour some lead ducks for fairing boat lines. (relax, it's only a model)

You should document the model making here. I'd enjoy that, and I know others would too.

02-21-2017, 10:10 PM	#1
footfootfoot To shreds, you say? Join Date: Aug 2004 Location: in the house and on the street-how many, many feet we meet! Posts: 18,449	How funny, I just made a plaster mold to pour some lead ducks for fairing boat lines. (relax, it's only a model) I learned lost wax bronze casting and mold making in school. You can pour lead or pewter into a plaster mold, but you sort of did it backwards, Make your master positive out of something like wood or wax then make a plaster mold of your master positive. If there are no undercuts the positive should pop out once the plaster sets up. You can use your carved plaster as a positive if you seal it really well and use silicone or something as a release agent. When you've made tour plaster mold let it dry thoroughly. an hour or so in a low oven should do it. You can now pour the pewter into the plaster mold. Another way to get a really detailed mold for one-offs is to get some dental alginate to make your mold. You can pour several wax positives with it before it dries up or falls apart. Then you can pour plaster over the wax positives, encasing them fully but allowing for a sprue and a vent, You melt the wax out of them (outside, low campfire coals be sure to add sand to the plaster to give it strength) Then while still somewhat hot you pour the metal. __________________ The internet is a hateful stew of vomit you can never take completely seriously. - Her Fobs

02-21-2017, 11:28 PM	#2
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	I accidently forgot to take some Bismuth alloy out of my pocket, and brought it home. It's bad if you get fired taking something out but a damn fool if you get caught bringing something back. This Bismuth alloy melts at 158 degrees F (yes it'll melt in hot water), we used it in tooling to locate bushings in drill fixtures where the old bushing was ripped out leaving a huge hole. It also expands slightly when it cools holding the bushing tight. My buddy used to do a bunch of wood carving and he bought some silicone mold material so we cast several of his carvings. This one is about 3" high and has good detail. I mounted on a piece of Cocobolo scrap with some stars above and a wood chip that looks like a butte below, calling it, "Between Heaven and Earth" Attached Images __________________ The descent of man ~ Nixon, Friedman, Reagan, Trump.

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