Slate coaster tricks

[wenning08]

I made some videos on slate coaster tricks that you might find interesting.

This one shows how to sand down and start over with coaster engravings

Unlimited Redos for Slate Coaster Laser Engravings

This one shows an experimental coloring technique I came up with that I found neat

Experimental Coloring Trick for Slate Coasters

[rvogt]

Thanks, I didn’t realize they could be sanded!!

[evansd2]

I posted about sanding slate back in 2017:

Settings for Engraving on Slate

I just found out that rescuing slate from a botched engrave is possible. I started something and realized I screwed up a setting, so thought maybe the coaster was ruined. 400 grit sandpaper and 3 minutes later, I was able to completely remove the screwed up portion, apply a tiny amount of mineral oil to darken the area and remove the stone dust, and start again. It looks perfect, actually.

It’s pretty easy to restore slate, the sanding process is fast and easy.

[rvogt]

I need to go back and review some of those things!

[chris1]

I was just playing with a black light and I noticed that slate engravings glowed a deep purple. I also learned it’s no use trying to photograph it.

[wenning08]

Can’t catch it on camera?

[chris1]

My phone camera, at least, is 80% software, and corrects everything to take natural looking pictures in visible light. I’m pretty sure dark fluorescent purple is just too far out of what the algorithms are expecting and it shifts it to a bright blue.

Ok, by using a camera app with full manual controls and really tweaking the white balance, I got something close.

[deirdrebeth]

That’s gorgeous! Off to go find my UV flashlight!

[deirdrebeth]

Mine didn’t glow as much, but definitely purple. You could also see what looked like green inclusions in the slate outside the engraving.
Do you mineral oil or anything for finishing? Mine are plain so I wonder if that makes it brighter.

[eflyguy]

Several common minerals fluoresce under UV light. Ruby, Fluorite, Calcium are some. If you go into a dark cave with a UV light source, the walls will glow in places. Also, places that sell interesting rocks and crystals will often use strong UV light to make them fluoresce.

Edit… thanks for the rabbit hole!!

Slate often contains fluorescant minerals such as: fluorite, opal, calcite, aragonite, apatite, chalcedony, sphalerite.

Composition differs based on origin and formation.

[chris1]

I sprayed shellac on before engraving, but that would be removed in the parts that glow. Probably just the picture making it look brighter than reality. It’s not a dramatic effect, just thought it was neat.