Someone just asked me if it was possible to make a branding negative. They were thinking about cutting their pattern in wood and then pouring iron in it to create a home branding iron.
Anyone know if that will work? Thoughts?
Initial thought (with a quick google to confirm) is that it could work great to make a pattern to press into molding sand, and then cast from that:
7 Likes
I like @jbv 's idea, but I might recommend using acrylic. Seems like wood might be too “grabby”. You might want to do something similar to the way people make rubber stamps, with reinforced sloped edges… kind of depends on the design.
Pouring iron is not such an easy thing. I was working for a company that cast Stainless steel and they had induction pots that did not let air in till the moment of the pour, and then it was very hot, far more than bronze etc, and why the bronze age was so long before the iron age.
You could get something from good casting sand if only the shape and not the support, but ceramic shell casting would be needed for anything complicated. Wood models will work in sand, but ceramic shell needs wax. You could use a bronze branding iron but you might need a longer one as the heat travels up bronze pretty good.
2 Likes
So…
plexi positive
silicone negative
wax positive
ceramic negative
…Then cast your metal positive?
(EDIT: It should be noted that I have no idea what I am doing.)
3 Likes
The ceramic in this case is weird stuff. You have to keep it constantly mixing or it turns to a wet rock. In college it was the job of every student in sculpture to run the power mixer (looked like some weird alien rifle) to keep the slurry in suspension and it was still lumpy. you coat the wax in that stuff and then roll it in fancy cat litter looking stuff and let that dry and then several more layers.
Ah, so it’s more complicated than just the simple lost wax castings I did in silversmithing courses.
I think you can mitigate the conductivity problem of brass by fastening a handle of a lower conductivity. Winston Moy used a handle made out of what looks to be a lead screw (probably steel) with a turned wood handle:
2 Likes
Rockler Woodworking will actually sell you one. you supply the artwork/design. they have torch heated and electric models.
3 Likes
The problem is that casting plaster works great for small things, but the square-cube law will come bite you as you go up in scale. double the size of your casting and the volume goes up 8 times, toss in a centrifuge and you multiply the forces by a lot more than even the 8 times . This combined with why northern squirrels are a lot bigger than southern squirrels and the practicality goes down hill fast. if your branding iron is bronze and the size of jewelry the plaster method will still work.
2 Likes
Thanks all. I am/was already planning on checking out Rockler and now really need to. Also, fortunately for us, we have a metal museum here in Memphis that apparently does commissioned works. Worst case is that if I can’t do it, my friend can always go there and get it done.
1 Like
Wood has been used for patternmaking in sand molds for thousands of years. For durability they are sometimes shellac’d. They also use talc as a mold release.
Did someone say shellac?