Dallas Makerspace Show & Tell - July 2018

Are the glowy rings self-powered (radioactive)?

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No, its solar charged strontium aluminate powder. I’m not brave enough to play with Tritium vials just yet.

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I thought strontium was slightly radioactive?

Yesterday I officially finished a tray I made per my wife’s specifications. It is about 15" by 10" with an interior depth of 3/4 inches. Cutting was done on the Multicam CNC using a 1/2 inch down cut bit to clear most and a Bowl & Tray bit (that provides the rounded interior angles) to finish pocket. For the bottom edge, I used a 1/4 inch roundover bit on a handheld router. “Logo” on back was done on the CNC with a 60 degree v-bit. Sanding and mineral oil by hand. She’s thrilled with how it turned out!

Plan is eventually to do both a smaller and larger version in other hardwoods that will nest.

Apple and ritz to help with size, not because I was hungry.

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You’re supposed to use the internet-standard-banana for scale.

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I had to double check, but it is not- There are two types of Glow-in-the-Dark (GITD) technology in use today, one is Zinc Sulfide and the other newer form is Strontium Aluminate with Europium as an activator. This powder (or crystal) is a non-radioactive phosphorescent pigment produced from rare-earth elements and provides an extreme long-lived afterglow.

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@Webdevel, I don’t eat bananas!

You could always print one (preferably out of yellow ABS)…

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But could you print it in 1:12 scale??

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I would think you could on the resin printer and still capture the scale detail.

Continuing casting bronze pieces. The shiny seahorse and rabbit I did a month ago (or so). This month I did the other seahorse and the dog but I’m not finished polishing them yet. I also did the two square fasteners.

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Some questions:

  • What furnace did you use to melt it?
  • Did you buy raw bronze or scrap?
  • What was mold material?

Very cool. Thanks

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The black jeweler’s furnace in JSM gets just hot enough to do a pour of bronze if you’re quick. About half the time the metal starts going solid before I can finish pouring but I think I’m getting the hang of it.

I didn’t use scrap bronze, I used bronze casting grain purchased from Rio Grande jewelry supply. They advertise that it is 90% copper and 10% tin, so I don’t have to worry about it having zinc or lead in it like I would if I used scrap. I could possibly make my own bronze using copper electrical wire and lead-free plumbing solder, but the Rio Grande stuff casts pretty clean and doesn’t cost too much.

Mold material was jeweler’s investment and it was done as a lost wax cast. I’ve done casts using other things, like plaster of Paris mixed with sand, homemade sand casting, Petro-bond sand, and Delft clay.

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Thank you -

Found it on their site, the “Ancient Bronze Casting Grain” Like that it is Zinc free.