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Discussion Starter · #1 ·
I've painted a few murals using oil paint mixed with ((oil-based) polyurethane which give a brilliant durable result (eg outdoor on sealed masonry or cement)

I've got some ultraviolet pigments which I've been mixing in oil and painting with, combined with traditional artists colours.

What I'd like to do is use them in one of the polyurethane murals,but the polyurethanes I've tried block ultraviolet entirely so the pigments can't fluoresce. I think the brands marketed as 'exterior' products have a specific UV blocker added. (I can't remember which brands I tried, it was one or 2, sorry) Can anyone suggest a product that would work?
 

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I've painted a few murals using oil paint mixed with ((oil-based) polyurethane which give a brilliant durable result (eg outdoor on sealed masonry or cement)

I've got some ultraviolet pigments which I've been mixing in oil and painting with, combined with traditional artists colours.

What I'd like to do is use them in one of the polyurethane murals,but the polyurethanes I've tried block ultraviolet entirely so the pigments can't fluoresce. I think the brands marketed as 'exterior' products have a specific UV blocker added. (I can't remember which brands I tried, it was one or 2, sorry) Can anyone suggest a product that would work?
Well, now that my friend is a good question! I couldn't tell you the science behind it, but of course the exterior polys will have a UV protector in them. What sheen have you been using? Could you maybe just use an interior poly product and cross your fingers. For what it's worth, Waterbased products will have a clearer finish to them, then the oils. That's all I got.
 

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"Clears" without a UV blocker will fail. They will cloud over, discolor, and often peel and lift. Not advised.
Most clears will fail outdoors in direct light without a UV blocker.
 

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Discussion Starter · #4 ·
I've used gloss(mostly) and satin for murals in the past, mostly gloss. But I'd be Ok with any finish as long as colour stays true, no yellowing

Thie projects I'm planning for won't be exposed to direct sun, tho damp will be unavoidable. There's 2 tunnels which will be made from prefabricated cement sections, and under a pair of bridges over a (brackish tidal) canal with some paint on preexisting work as well as probably cement boards we attach painted. Lighting will be LEDs, RGB plus 390nm UV
 

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Discussion Starter · #5 ·
Trial and error it may have to be. When I asked Wattyl - a local manufacturer they said they had no data -end of discussion.

I did see the precis of a paper on a UV transparent polyurethane for use in LED fabrication, so I think its probably possible as a paint as well, but that was pretty recent, and UV protection is what most users require
 

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That question has come up before on the Internet. I don't know if it has ever been satisfactorily addressed.

I would query Glowstop.com and ask them.


Manufactured according to the latest in self-emitting light technology, our photoluminescent glow in the dark products are acknowledged to be the best and brightest in the market, meeting and exceeding many international standards.

They are located in New Zealand so probably better to write than to visit.

By Email
Do you need to contact GlowStop about an order? Have a question about one of our products? Want to send a compliment or complaint about our services? Have an idea you’d like us to consider? Please email our Customer Services Team at [email protected].
 

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Discussion Starter · #7 ·
Thanks very much for that tip abut GlowStop. I'll send them a query and update here if I get any interesting information back. I'm in Australia so NZ isn't far away
 

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Thanks very much for that tip abut GlowStop. I'll send them a query and update here if I get any interesting information back. I'm in Australia so NZ isn't far away
My brother-in-law is taking 15 of his close friends on an all-expense-paid trip to New Zealand for three weeks in December. I didn't realize I qualified as one of his close friends so that is gratifying, especially since the friendship outlived my sister.

I am looking forward to that trip. (But I will not be searching for non-UV absorbing poly at that time.)😀
 

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Discussion Starter · #9 ·
I didn't get any responses but it turned out the answer was sitting in my workshop.

I had some molding epoxy which I decided to use to fill a tabletop from old timber slabs(so now I'll have to put blacklight in the kitche LOL). The UV pigments work fine in that (I didn't try mixed with oil). But it got betterwhen I saw I had a tin of 'Cabothane', a polyurethane varnish. I thought I'd tried this stuff before but I must not have as the pigments fluoresce well behnd it or mixed in it. There won't be any problem mixing oil paint in it either.

From that I'd guess that clear polyurethane is clear to UV(at least the near visible wavelengths that interest me) as well unless it has had some UV blocker added - 'exterior' formulations. Unfortunately I didn't get the job to paint the tunnels etc, but I'm looking forward to trying this out now
 
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