Well, I've never done an outdoor plywood sign before. (In case the Q sounds silly!) What should I prime it with? Thanks always in advance, y'all!
Posted by cheryl nordby (Member # 1100) on :
I might get some who disagree.....but the best finish for me is when I take the oil based enamel and do about 2 or 3 coats. No primer. The first coat sinks in pretty good. Be sure to let each coat dry before adding another. After the first coat..put the filler on the edges and sand.
Posted by Janette Balogh (Member # 192) on :
Hi Felix,
I'd also be interested in the answers here.
I've been using the same thing for many years.
Ronan Block Out.
It's worked great, but it seems as though my boards don't endure quite as well as they used to in the past. Don't know what to attribute this to. I have signs out there that are still great after 10 years ... absolutely no exaggeration.
Lately I don't see the same endurance taking place.
Curious to know more about other primers. Janette
Posted by Wayne Webb (Member # 1124) on :
I have had good success with Zinnser's primer topcoated with Ronan or OneShot Bulletin enamel. Got some 7+ years old with no adhesion problems. Paint is fading but no peeling. I have primed with Jay Cooke's and topcoated with Acrylic latex on MDO but they're not that old yet. Seem to be holding up fine so far.
Have seen several of my competitor's MDO signs with the paint flaking off bigtime and just a couple years old. I don't think he uses any primer at all.
Posted by Ken Henry (Member # 598) on :
I've switched to Behr's Acrylic Exterior Latex primer, after many years of using oil based Block Out White. I also finish coat using the Behr's Exterior Latex so that the systems are compatable. They have a great pallette of colours available, and have the advantage that they "breathe". This prevents the blistering and flaking off which seems to be more prevalent with the more recent oil based finishes.
Posted by cheryl nordby (Member # 1100) on :
I have seen people not use primer with latex paint...and it does not last. Oil base paint without primer I have used for quite some time. I read in one of the sign magazines about this a few years ago. It does work, but only with oil base paint.
Posted by John Martin Robson (Member # 1686) on :
Quality paint is one thing (BM Impervo)………but a well prepared sign board is essential.
My understanding of primer or priming is to allow the paint to soak in to the fibres, or substrate surface. This is best achieved with thinner paint (primer) & a rough surface.
1. fill edges )wood filler, silicone or putty), sand, and scuff surface……insure board is dry and clean 2. Prime, 1st coat, sand …… fill pits & edging again if required. 3. Undercoat, 2nd coat 4. Finish coat
Note: the backside only requires 1 or 2 coats if the substrate is against a wall or backing.
Posted by Felix Marcano (Member # 1833) on :
Thanks always!
Posted by Lotti Prokott (Member # 2684) on :
Felix, the most important part is that you use a good signboard and not regular plywood. The one we have here is called Crezone and has a smoth paper finish that does not crack like regular plywood. Then just follow John's instructions step by step. I alway use latex undercoat on both sides as it soaks in well and dries fast.Then good alkyd paint, 1 coat on the back and 2 or sometimes 3 on the front. Benjamin Moore has the brightest white for the top coat. And second most important part: have fun!
Lotti Posted by Glenn Taylor (Member # 162) on :
An ol' timer got me to quit using primer.
Yeah, I know. He's nuts. But it works.
What he suggested was mixing 50% mineral spirits with 50% oil-base enamel and using it as the primer. This allowed the paint to soak in better. Once dry, apply two coats of oil base enamel as you normally would.
Every board I've done that way lasted much longer than the ones I did in the traditional manner.
Also, the suggestion was make to lightly sand off any sharp edges or corners. Its usually in these places that paint starts to peel. Knocking off the sharp edges helps to prevent this.
Posted by cheryl nordby (Member # 1100) on :
Yes Glenn! It does work!
Posted by Glenn Taylor (Member # 162) on :
By the way, I forgot to add something....
If you can get "regular" Thompson's Water Seal, you can substitute the mineral spirits with it. Its already 95% mineral spirits anyway.
I have found that it helps the board last longer in wet or damp areas.
Posted by John Martin Robson (Member # 1686) on :
It’s a good thing so many people add to a post like this………….cause its so easy to assume stuff. I didn’t even mention MDO or Crezone (thanks to Lotti Prokott )……….which is pretty important.
Glenn Taylor........... good point on edges. I have just recently started to router the edges, it not only looks great, but the paint has more surface area to adhere to…………just creates a better quality product.
Which means you can demand top dollar for your product.
Most of what I’ve just said……………I discovered right here.
Posted by Rick Sacks (Member # 379) on :
When I see the old signs that are just faded and the stuff in the past ten years that flake right down to the surface of the MDO, I start asking questions too.
There were formula changes in primers to meet EPA requirements. Paint companies change the formulas and not the labels and we think we're using the same ol' stuff that worked.
I've found the flaking with Jay Cooke as well as block-out's and Z-Prime. I have not found a formula that works near as well as the old white lead paints.
Posted by Santo (Member # 411) on :
The boat carpenter I worked with always finished his own sign panels. He used more marine plywood and spanish cedar. Once sanded and filled, he used 2 coats of sanding sealer sanded between coats. Then he coated with marine enamals.
[ March 08, 2002, 10:56 AM: Message edited by: Santo ]
Posted by Janette Balogh (Member # 192) on :
This is certainly a day of learning for me on the ol' BB.
I'm real intrigued by what Cheryl says here and Glenn's follow up to it. Since I use oil based paints quite often, I'm gonna give this idea a shot!
Thanks!
Nettie
Posted by Felix Marcano (Member # 1833) on :
Well, I was just talking with my uncle, a retired auto body man.He suggested sanding sealer as well. Geez! Choices choices!!! Thanks so much folks!
Posted by captain ken (Member # 742) on :
I was using an oilbased prime for many years X-I-M and within the last year have completely switched to Jay Cooke's top coated with Ronan Bulletin color.
Posted by Rick Sacks (Member # 379) on :
Since all the failures I see are revealing weathered substrate, is it fair for me to claim a primer failure?
Since I'm seeing it with both the solvent based and acrylic primers I'm inclined to try the primerless method or investigat eurethanes or epoxys. I'd sure like a single stage epoxy that doesn't have a smell that screams "toxic" at me when I use it. Anyone experimenting here?
Posted by Glenn Thompson (Member # 1851) on :
I'm going to give Glenn suggestion a try today on 4 4x8's I have to get ready. Sounds promising
Posted by Glenn Taylor (Member # 162) on :
Just wanna add.....be sure to lightly sand between coats. I always considered that to be a given, but I've been surprised by how few actually do it.
Posted by Ricky Simpson (Member # 1318) on :
Cheryl,
Interesting that you use the finish coat "thinned" as a primer. I like the idea but it seems one would lose the advantage of the primer being a quick drying coat. Usually in a couple of hours one can follow up primer with the finish coat. Do you add xylene or another additive to speed the drying time of the "primer" coat?
Posted by cheryl nordby (Member # 1100) on :
Ricky....I don't thin the finish coat....or any coats.
Posted by Brad Ferguson (Member # 33) on :
Glenn mentioned sanding between coats. Does anyone sand the MDO paper itself before the first coat? Yes, it already has tooth, but would more tooth help? Just curious.
Also, if the money's there, another good solution is to not use MDO at all, but one of the aluminum composites.
Brad in Kansas
Posted by James Caley (Member # 2743) on :
Don't use raw plywood in the first place,.use MDO. (Medium Density Overlay,..... plywood) Kilz II, or the Zinser product work good. If you can't get MDO,.make sure you get your plywood from a REAL lumber yard, not one of the discount "Home Builder" places,.....They don't have properly dried wood, and the background paint will not stick for very long. NEVER be tempted to use anything but REAL background paint,.from a sign supply place,..NEVER use Rustoleum!!!( for instance)...last time I fell for that , it took 3 days for it to dry!! In short,......Use the real stuff, .....don't try to cut corners or expenses!.......Charge enough to do the job right!
Posted by Glenn Taylor (Member # 162) on :
Ricky,
I "thin" the first coat with a 50/50 mix of oilbase topcoat paint (usually OneShot) and mineral spirits (the cheapest I can find works fine). Yes, it does take longer to dry; usually 24 hours and sometimes more depending on the temperature. I then apply the next two coats at full strength.
While this makes it take a day or two longer to do, it has added several years of life to the panel. If you use Thompson's Water Seal (regular flavor - don't use Thompson Ultra), you may need to let the primer dry an additional day or two.
Brad, I do regardless of the other prep work I do to the board. The panels I do don't have the paint peeling off the faces in sheets like my competitors' do.
[ March 10, 2002, 06:58 PM: Message edited by: Glenn Taylor ]
Posted by Mike Kelly (Member # 2037) on :
I buy Simpson pre-primed MDO from my supplier and haven't had a failure with it in the three years since switching from the unprimed. I don't know for sure but it looks like oil based. Of course I reprime the edges as well as seal them. Primed boards cost about $10 more.
Posted by Checkers (Member # 63) on :
I've been taught to use preprimed mdo, I've never used plywood. It's similar to Nettie's method. Sand the faces lightly and knock down all sharp edges. Clean with paint thinner. Fill any gaps in the edges with wood puddy then prime with fast dry block-out white and allow the panel to dry overnight. The next day, sand slightly and clean. Then follow up with 2 coats (3 if using burgundy) of your background color, sanding between coats, and finish accordingly. Depending on the weather, the whole process can be completed in 2 or three days. BTW, I paint the edges first & clean up any drips or runs, then the paint the faces. I also paint the entire board at once (both sides & the edges). My old boss has been doing this way since he started & he still has signs up that look great & are over 10 years old. Havin' fun, checkers
Posted by Doug Allan (Member # 2247) on :
Brian, how do you do both sides at once? I have ocassionally put 2 nails in each of the 8' edges, & after coating out 1 side, flip it to rest the nails on 4x4 blocks to coat second side. It works if I'm in a rush although more filler needed on edges after.
I'm going to try the extra coats of one shot enamel instead of primer ideas.
Posted by Bob Rochon (Member # 30) on :
Glenn,
One thing about that process of priming that concerns me is that you primer coat is thinned excessively.
We have read here many times about thinning our top coat as being bad, How is thinning top coat effective in sealing MDO as a primer?
I understand that by thinning it it will penetrate deaper, but I am confused about it's protecting properties. especially if you are using only one coat of primer.
Posted by Santo (Member # 411) on :
How is thinning 1-Shot for a primer cost effective? I believe you're going to start adding a lot of costs in doing this for a large number of panels.
Posted by Rick Sacks (Member # 379) on :
So has anyone tried any of the marine epoxy primers yet?
Remember when we'd see enamel peeling off the panel and you could still see the primer? What I see these days is the MDO because of primer failure.
I question using diluted enamel to obtain the tooth needed for long term durability. I see signs I did 25 years ago that are just faded, and long to return to that type of security when I sell a job.
Posted by Glenn Taylor (Member # 162) on :
Well, just to make sure I'm understood properly....
Only the first coat is thinned. The next two coats are done at full strength.
I never said that this was cost effective, only that it works. I don't have the paint peeling after 3 years. I've got panels out there that are better than 12 years old in full sun that look acceptable. No paint is peeling, even around the edges.
Other than that, all I can tell you is that it works for me. I've not had a single failure using this method.
Posted by Bob Rochon (Member # 30) on :
I can see a test panel being cut today in our shop.
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