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Wow! Sorry I missed the live version of this chat. Having used light cured dental materials for years, I can guess the answers to some of your questions. Beware, these are only guesses because the dental materials are similar, but likely a bit different.

First, as far as wearing the orange glasses - it’s a darn good idea. Repeated exposure to a bright light, especially with blue components, will likely promote cataract formation. I do not believe any controlled studies have been done, but why risk it? FWIW, I just had two cataracts removed. Was it due to my years in dentistry? Who knows? It’s fixed.

With the dental materials, the secret to layering is not removing the “air inhibited layer” (a layer of unset material on the surface) on top. And somehow, this stuff doesn’t have that problem. I would be interested to see how that has been handled. The layer was removed with alcohol.

The problem with the dust from grinding these dental materials are the silica particles embedded in them that provide wear resistance. Wear your n95 while sanding and turn on the suction. Simple enough.

My guess is that curing with the big light achieves a couple of things: more cross linking so that (as Ian mentioned), you can walk on it for a hundred years, and depth of cure. Of course sunshine is the low cost option, but I wonder if these are the same wavelengths used in autobody shops? (I know a guy…)

Re: toxicity - the raw material is volatile and likely has toxicity, but once cured, you get the food grade surface. I found that contact with uncured dental material was not a good idea - it’s definitely rash-worthy over time. The raw material is a two part material infused with a light sensitive catalyst. When light of the proper wavelength and strength hits it, the molecule breaks apart and becomes an active catalyst. So the light doesn’t harden the material directly, it activates the catalyst.

I’d love to hear Bryan’s and Dan’s thoughts on mixing colors with these materials. With the dental materials, pigments were suspended in the resin. But the size of the particles must have been fairly large, because when you mixed colors, it was more like a Seurrat painting (pointillism). I remember layering colors to achieve the proper effect.

I hope this helps. I am really looking forward to the next session. This stuff sounds like a real game changer. (This guitar will be tough enough to walk on for 100 years!)

Cheers.

Rick