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The K0BSR Ring

I was contacted by email from an amateur radio operator, Ben K0BSR, in Colorado. Hams reading this will know how to find out more about him.

He saw my silver work and wondered if I could make him an amateur radio callsign ring. I have made several versions for myself and my own radio call sign.

I asked him for suggestions and he came up with the idea that he wanted it to look like a portable HF radio. That seemed like a good design challenge for me.

I have been playing with three-dimensional printing and thought this was a great project to create using 3D printing to make the master model for casting. It was a process I hadn’t tried, but this seemed like a good project with which to start.

The CAD was straight forward. My first design had a solid “body” and would have been a heavy ring. I discovered the 3D DLP printing was going to be the major problem part of this project. The printed model also caused a lot of problems in the casting process. This successful design has a lighter design to improve on casting issues.

Professional big shop jewelers are consistently using 3D printing for making master casting models. Their equipment is packaged complete systems for performing this task. When you have a sizable business casting silver, a $10,000+ 3D printing system is no problem. The early adapters paid $30,000 to $50,000 for equipment. Cost is coming down, but not into my range.

My total investment limit is around $500. I have a Wanhao D6 DLP printer. First prints using standard printing materials worked quite well and I produced excellent results. Making silver casting requires a special material be used for the printing that will burn cleanly out of the mold used for casting the silver.

I went through several brands of this printing material and at least a dozen printing runs before I could produce quality master models of the ring design.

Then to my disdain, I discovered the material doesn’t burn cleanly out of the mold. In early trials the material attacked and eroded the inside of the mold cavity.

After several months of trial and error exploration of scores of variables that need to be understood and managed, I have found the correct combination for producing satisfactory results. I kept telling myself, “If it was easy, everyone would be doing this”. I also had some long distance moral support from a instigator friend up in the state of Michigan.

This ring has gone though a lot of development. It has created a new process I can use in my silver casting process. For that I am grateful. It’s been printed at least a dozen times (sometimes multiples) and cast four times. This last one has been deemed worthy to send off to Ben.

There is a moral to this story. If I become bored with successful repetitive routine, all I have to do is try something new, that has little or no instruction. Developing a procedure from scratch, removes every bit of being bored with routine. No pain, no gain…

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