Protecting painted signs from weathering

[Sue Maesen]

Any suggestions for protecting the top edge of painted signs from the sun? What paint are you using to prevent flaking, etc.?

[Kelly Thorson]

Hi Sue

I'm not sure what kind of signs you are talking about, but if it is MDO, I like to coat the edges with something like either West Systems Epoxy or Titebond glue before painting. This seals the layers so the moisture can't get in and seems to prevent the peeling and flaking. I've often though about trying PB Resin to dome the top edge on high end signs, as that would make it shed the water. Although they get a lot more sunlight along the top edge I suspect the peeling has more to do with water sitting along the top and working it's way under the paint. When I do HDU and cedar signs I try to dome the top slightly and knock off the edges and that seems to help promote the water shed. Rounding the edges also seems to prevent chipping and peeling, but if you are going to seal with something like epoxy or resin I'd do it afterwards so you don't loose the crisp edge that creates surface tension.

There are a number of UV clears available, but I tend to steer away from them after experiencing some bad yellowing on a couple of the industry standards.
If you have a good quality paint and no water can sit you shouldn't have too much trouble with flaking.

[Doug Bernhardt]

Great advice above and would only add that I tend more and more to put aluminum flashing (like roofers) across the top of anything that sits unprotected on a wall. It is way too easy for mouldings to delaminate etc. I also epoxy seal edges and that does go far but paint layers over that will still peel. I have had good luck however with clearstar acrylic overcoat and it also goes on everything leaving the shop. It just fits with the way I work, all paint etc.