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Name: Ross J.
Status: student
Age: 17
Location: N/A
Country: N/A
Date: 2001 - 2002


Question:
Hi! I am trying to complete an "engineering" project for my Eagle rank in Boy Scouts. I am providing a number of signs for a local Georgia nature trail, each with computer-generated text on a paper backing, to be mounted on wood plaques. Can you help me identify a sun-resistant, clear coating that I can apply to protect them? (I am thinking about a polyurethane varnish, fiberglass resin, or a clear epoxy, but I am not sure if these will not yellow, crack, or fade. I contacted several tech support sites of both paint and fiberglass companies, but none responded.) Many thanks for your help,


Replies:
Without a clearer picture of how your panels are configured, it is difficult to make detailed recommendations. But consider the following:

1. The inks must be light stable. This means carbon blacks, iron oxides for yellows, reds and browns, phthalo blues for blue. Check out "Jerry's Artorama" on the Web at http://www.jerryscatalog.com for light stable pigments. Pigments used in inkjet printers are not likely to be light stable. Art supply houses may also carry lines of light stable pigments -- I'm not sure.

2. The papers must be light stable. This means an "acid free" archival grade which are at the above source or other art-suppliers.

3. An exterior grade urethane would be a good selection to seal the wood plaques, and there are ultraviolet-stable grades of Plexiglas you could use for the front face to protect the printing and paper from ultraviolet light. You can obtain these from most any glass supplier.

4. The Plexiglas, and the exterior grade urethane won't yellow, but you should stay away from epoxies which generally do not fare well under exterior conditions.

Hope this is of some help.

Vince Calder



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