You never know when a very small idea that is just a flicker turns into a consuming event. Such an idea came when I was making hollow pendants from the round dapping block. I tired of those quickly and wanted to do my own shapes. While researching it I came to the conclusion that I didn’t want nor could I afford a hydraulic press and a pitch pot. So what to do: make your own with collected scraps and some bondo. We have leftovers from the many projects that we do and I keep things I should probably throw out but “OOPS” might need that someday.
A picture tutorial of the steps to make a hollow form set up: With each picture I will add a few words to explain.
One of the hollows from the doming block.
Supplies you need. We had some aluminum left over from making mold frames for the RTV molds. I used Sculpey to press the object into since I needed half of the oval. The Sculpey is easy to pull out when the Bondo has cured. I only filled the frame 1/3rd with Sculpey and pressed the oval shape into it. Before you mix up the bondo you need to spray the complete form with mold release. All on the inside. Make sure you get a very good coat so the bondo won’t stick to “anything”. I spray and then wait a little bit and then spray again. Be generous… Mix the bondo according to directions on the container. Pour on top of the oval slowly so you don’t get air pockets. Set aside and let cure. It will get very hot and when it is cool to the touch you can take it all apart. The little voids in this first one did not interfere with the shape.
To get a crisp edge on your copper and have a line to follow when you saw your piece out you need the brass plate. The opening in the brass plate needs to be the same shape as your oval. I put a few layers of scotch tape on the bondo to trace pattern that I could transfer to the brass. Drill holes on each corner and bolt together to keep secure. I used the brass plate to position the holes for the copper after I annealed it. You can do this for each additional copper sheet. While you are marking the copper for the holes also mark your oval so you have an idea as to where to start dapping when it is all bolted together. Bolt it all together making sure that the brass plate is under the annealed copper. Ask me why I know this…..since I put the brass on top one time. A heart that I carved and made two set-ups since it would be opposing and not symmetrical like the oval and circles I had been doing. A good dapping with the steel dapping tools. Bigger tools to make the heart a little smoother. There are so many textures you could do. After you have sawed out your shape it needs to be sanded very flat so the two sides come together nicely. Also you need to file a round shape where the jumping will go. There may need to be a little tweaking to get everything lined up. Clean one heart close to the edges for the flux to stick. You don’t need to clean anything else. You just need a clean place for the solder and flux to adhere to. We use Handy Flux. I started with it and have never changed since I got used to it and it works for me. I flatten my wire solder to thin it out. It makes it easier to lay close to the edge of the piece. I cut it into little snippets and use more that you think you should. It will fill up the seam and keep any excess inside. You just want to be assured that you have enough and there will be no voids in your seam. I heat the flux and snippets so slow that the flux dries out and the snippets don’t jump around. Take your time here with a very soft flame and pick any pieces that jump. You want your soldier to be close to the seam so it will wick when you torch it. After the solder is half melted you need to file the edge flat again to clean it. You need to hold your piece down so the heat and solder will not make it jump and reposition itself. The third hand gives just enough pressure to keep it in position but not distort it by mashing it. I have a vacuum hose close to my soldering station. Right after the seam has soldered I add the jumpring. I don’t pickle the piece at any time. I hold the hot piece up to my vacuum hose to cool it off instead of plunging it into water. Cools slower and does not shock it. The finished and softly polished hollow heart.
I hope this makes sense and if there are any questions I will be glad to respond.