Gentlemen:
I’m building an Electrical/Electronic Radio Frequency Entry Panel for a Ham Radio station operator.
The base of the entry panel is a piece of 3/4″ plywood 15″ x 8″ by 3/4″.
Bolted to the plywood is a heavy, thick rectangular piece of aluminum 10″ by 5″ by 1/2″ thick. The composit panel piece is mounted almost at earth level on the outside of a stuccoed concrete block building using tapcon screws through the plywood. The plane of the Entry Panel is parallel to the plane of the external surface of the stuccoed concrete block building.
Various electrical cables and a 2″ wide copper grounding strap terminate on the aluminum piece. A double-pole double-throw switch is mounted on the plywood external to one end of the aluminum plate.
The roof overhang of the building plus a a little “roof” of its own will shield this Entry Panel from direct rain. But otherwise, the Panel is outside and will be outside permanently.
Now here’s the question:
What is the very best way for me to coat the plywood so that it will
stay resistant to rain water for as long as possible?
The owner would like the coating to match the color of the stucco.
Any suggestions are appreciated.
Thanks,
William
Florida
Replies
The best way? Use marine grade plywood and paints.
Namaste,
Gary
http://gwwoodworking.com/
Too late to epoxy the back surface? I just did this same process to my business sign - 3/4" ply tapcon'd to block wall. First, I used WEST system epoxy to super seal the ply edges, back and face. Slow epoxies soak in better than others, and WEST is marine grade. Then I glued and screwed the panel to the wall. Then I ran a bead of silicone at the ply / wall interface to keep the moisture from getting behind the ply.
Just marine paints won't do it - ya gotta seal with epoxy first, then marine paints, but the epoxy is so good, that polyurthane porch paint will topcoat it well and will last. Don't just use epoxy - it needs a topcoat for protection from sunlight, but you need to match stucco, so I'd thicken the porch paint with sand before application, then silicone the wall interface. If you want to seal against the wall first, then I'd use PL Premium Polyurethane window/Door sealer - its as good of a seal, but is also paintable - silicone is not.
"The furniture designer is an architect." - Maurice DuFrenes (French Art Deco furniture designer, contemporary of Ruhlmann)
http://www.pbase.com/dr_dichro http://www.johnblazydesigns.com
I second DrD's plan - epoxy with a marine paint topcoat. Use a penetrating epoxy formula; WEST has one, also Smith & Co. That will soak into the plywood and stabilize it against moisture penetration, even if the paint gets chipped.
"Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Sorry---I did a Google Search and found several dealers for the West
System in Florida.
Thanks,
William
Marine stores, like West Marine (no connection to the Gougeon Bros. epoxy), carry W.E.S.T. (Wood Epoxy Saturation Technique) epoxy kits.
Namaste,
Gary
http://gwwoodworking.com/
You can also order a similar product, CPES Multiprime, directly from the manufacturer:
http://www.smithandcompany.org/
"Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Another source for West System epoxy is Rockler.
John
You might want to try RAKA epoxy http://www.raka.com/ . They're in Florida, have very good prices, and did well in a test against all the major boat-building epoxies in a year-long outdoor weathering test: http://www.oneoceankayaks.com/Epoxtest.htm
You will also need UV protection from varnish on the epoxy.
Thanks a lot for these pointers! The exposure test in particular is exactly what I have been looking for.
I draw a different conclusion from that test: it looks to me like varnish is optional for furniture or other woodwork that will not be continuously exposed to sunlight. Even after a year of continuous exposure, the Raka and West System 207 panels hadn't changed much. Looks to me like a table top kept indoors would be perfectly fine without any varnish, if that was the look one wanted."Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
If you want it to match stucco, then why don't you cover it with...
drum roll .....
you knew this was coming.....
stucco. Its water resistant the same as the building.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I would second the RAKA recommendation. I have built half a dozen boats using RAKA epoxy and they have all faired well. Larry has always given me great service and his prices are some of the best around. I also agree with the comments about protecting the epoxy from UV rays. Without any paint or inhibitors, your epoxy will deteriorate relatively quick (faster than you think). Be sure to let the epoxy cure fully, wash off any blush with warm soapy water (waxy feel to the surface) and sand lightly before painting. While a marine paint will work, in this situation it may be overkill as the rain is intermittent. Any good quality enamel paint with a coat of primer underneath will be sufficient.
Keep safe-
BVL
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