I've got a piece of pressure-treated plywood that I need to do a sign on. I've been doing them for the last couple of years and I've noticed that some of my "older" signs (2 years old) are starting to yellow and weather. Upon listening and reading the posts on this website I've learned that the sign needs to be properly sealed before painting begins so water does not get between the layers.
1. I was wondering if someone could explain the process of sealing to me and what materials I will need to do this.
secondly, after the sign has been painted, is there a protective coat that is supposed to be put over the entire sign?
Thank you for any responses in advance...it's quite disheartening to see such time and effort go into a sign and then see it age so quickly.
Posted by Bill Lynch (Member # 3815) on :
You're painting signs on PT plywood? That's the start of your problems, if you want to do painted signs get some MDO plywood, the best brand you can get. Then seal the edges with Titebond exterior glue, prime & paint with good quality oil base paint, then paint your sign with lettering enamels.
Posted by John Arnott (Member # 215) on :
Use MDO plywood, not hardware store plywood. Never use "Customer Supplied" plywood. Prime it yourself with a 1/4" nap roller cover for the correct mill thickness. The precoated stuff is run through a roller coater and it's too thin of a coat to last. If you need to seal the edge better, put a coat of tightbond wood glue on the edge first. Use a good brand of top coat paint.
Posted by Checkers (Member # 63) on :
Hiya Jeff, Just in case you're wondering, MDO plywood is Medium Density Overlay. A quick google tuned up this description on BobVilla.com... Called MDO, or medium density overlay, it's engineered plywood with a resin treated fiber applied to both faces. This gives an extremely smooth finish that is easy to paint. In addition it's rated for exterior use, which means it is safe from the elements, insects, or other outdoor hazards, making it a perfect choice for the new deck or porch. Just like most other plywood, there is good and not so good. I prefer to use Olympic Panel Product's Signal brand, but there are other manufacturers.
Havin' fun,
Checkers
Posted by Jon Jantz (Member # 6137) on :
Nice, Bill & John....
Almost word for word. You convinced me, and I ain't even the one doing the job.
Posted by Si Allen (Member # 420) on :
Don't forget to ease the edges!
Paint does not like sharp corners and will crack, letting in moisture.
Posted by Dale Feicke (Member # 767) on :
The stuff that they pressure treat wood with will most certainly keep bleeding thru your finish coat. That's why you shouldn't use it. You can't seal it from happening. MDO is the way to go.
You won't have to deal with problems again if you follow the above advice. Good luck.
Posted by Darcy Baker (Member # 8262) on :
seal the edges of your MDO with titebond glue before you prime the blank.It'll save ya some grief.Jeff, don't clearcoat your work as it is the weakest link and will fail before your basecoat.I learned thru experimentation.When a sign needs to be repainted, that is another job for you!
[ September 04, 2008, 10:32 PM: Message edited by: Darcy Baker ]
Posted by Sheila Ferrell (Member # 3741) on :
Except for sand-blasted signs or applications where I need to have an old look (and even actually look better the more it ages) . . . I gave up any kind of material containing any kind of wood . . . The amount of prep work for even MDO and etc, became absolutely ridiculous to me when I could use aluminum which comes with a ready-to-letter OR paint surface, AND it never: warps, cracks, fades, peels, rusts, checks, splits, or rots.
The worst thing I've seen happen to an aluminum .063 was when someone threw a brick at the customers sign and it got a fairly small dent similar to a bullet-like bump. Virtually unnoticable from the street. Unlike a wood sign, which would have immediately started rotting where the paint broke.
Baked-finished aluminum (I rarely use mill-finish) can be custom painted any colour without priming. A simple scuffing of the surface and the paint can be rolled or sprayed to a glass finish. I use industrial enamels in the case where white is not the choice. For a much longer lasting finish, I often sell an automotive finish which stays glossy for several years.
Just an ideeer! Whatever you letter upon, jus' have fun at it!!
Edited for imperative corrections to spelling so as not to conform to sterotypes about sign painters not being able to spell . . . .
