4

I have gotten my hands on some powdered pigment that is uv reactive, meaning that it reflects UV light in the visible spectrum. I would like to use this pigment for a few projects outside. The pigments are more or less transparent in daylight so I want to use it to coat some outside items to they will light up when lit up with UV light.

My problem is simply that I am a complete troglodyte when it comes to painting. So I would really appreciate some help with picking out a paint or coat that is:

  • Transparent to UV light. If it reflects or absorbs the UV light, the pigment wont work.
  • Durable enough to be used outside.
  • Adheres to ceramics and wood. I am planning on coating wood and flower pots initially.
  • As transparent to visible light as possible.

I have been looking at coatings such as epoxy and polyethylene and acrylic, but epoxy seems to yellow in UV, and polyethylene seems to absorb it, while acrylic seems to be pretty brittle and (I assume) will then not be great for wood coatings. I would not mind using a paint, but I have no idea of what kind of base to use.

Elmy
  • 13,017
  • 3
  • 19
  • 42
Martin Nielsen
  • 141
  • 1
  • Have you considered that UV-reactive pigments fade quite quickly in sunlight? It's quite noticeable on some of my bike stuff and that's stored indoors. It may not be an issue for you, but you do mention durability – Chris H Feb 11 '24 at 19:00
  • Yes I have considered it. I am not painting something that cannot be thrown out later, and the pigments SHOULD be relatively durable. But I am definitely not painting the house with them :D

    Still, it would be nice to find something that lasts at least as long as the pigment to use as a base :)

     – Martin Nielsen Feb 12 '24 at 11:27
  • While I don't have UV pigments, I do have a UV torch, UV pens, and PU varnish. I may get the chance to test but not for a few days. It's possible that a thin layer of PU would be OK when a thicker one wouldn't – Chris H Feb 12 '24 at 11:30
  • I appreciate any help you are willing to give :) – Martin Nielsen Feb 12 '24 at 12:08
  • It could be helpful if you know what sort of phosphors you have. Some of the phosphors used in LED lamps are extremely resilient to UV radiation, as is necessary if they are to outlast the 10,000-hours plus lifetime of the LEDs. I'm thinking specifically of rare earth nitrides and copper/aluminium-doped zinc sulphide. However, these materials are sensitive oxygen and to moisture, so they may be quite vulnerable in your application. – george storm Feb 13 '24 at 20:29

1 Answers1

3

The shop SolarColorDust.com gives this information in their UV Pigment instructions (emphasis added):

Instructions for Use:
SolarColorDust® should be mixed at a ratio of 1 gram of pigment to 1 fl oz of a clear drying base.
This mixture can be applied to a WHITE surface in order to see a vivid color change!
Can be mixed into clear epoxy resin, neutral paints, Mod Podge, lacquer, varnish, clear nail polish, and more in order to be applied to a white surface.
Angelus Neutral Paint is recommended for applying to shoes and other textiles.

In addition to these options, you can also use a tacky glue (Aileen's Tack-It Over and Over, various repositionable spray adhesives, etc) to apply the pigment directly then coat with a varnish, though you may end up using more of the pigment in this way.

Also worth noting is that the instructions quoted above also contain a warning about leaving UV-reactive items in the sun, as doing so

will create a "sunburn" on the pigment eventually causing it to cease changing color.

Because the pigment cannot withstand extreme UV exposure, any medium you choose to mix it into should also be fine; color changes in these media are caused by extended exposure to UV, and an amount that would damage them would also damage the pigment.

Allison C
  • 4,044
  • 13
  • 32