posted
Okay folks. I've been treating MDO the same since I started. I've got 7 raw 3/4" MDO sheets that I need to prime and paint white. Will be applying vinyl graphics. How is everyone dealing with unfinished MDO these days? I have always used oil based products. Is acrylic latex the way to go now? Flat or semi-gloss? School this old dog in some new tricks.
-------------------- John Byrd Ball Ground, Georgia 770-735-6874 http://johnbyrddesign.com so happy I gotta sit on both my hands to keep from wavin' at everybody! Posts: 741 | From: Ball Ground, Georgia, USA | Registered: May 1999
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posted
Old dogs and new tricks...been there, done that.
We've been using water based acrylics on MDO for a number of years now. This is what we do:
1. Round over the edges with a 1/4" round over bit in a hand held router (or sand off the square corners with a random orbital sander).
2. Seal the edges with Titebond 3 wood glue - use a throw away stencil brush.
3. Fill voids with exterior spackling or epoxy.
4. Prime with water based acrylic primer (FSC 88 WB from Coastal Enterprises - thinned with water, Sherwin Williams A100 water based primer, Jay Cooke primer, Porter water based primer) We usually roll the primer with a 3/8" nap roller cover or spray with HVLP spray gun.
5. Sand lightly when dry with random orbital sander - 220 grit.
6. Apply finish coat of satin water based 100% acrylic - either by rolling, brush, or HVLP, depending on the size of the background. We use mainly Porter and Sherwin Williams Super Paint. Apply a good coat but don't keep going back trying to make it smoother - as it gets tacky you will just mess it up.
7. Lightly sand when dry and apply a second coat.
8. Apply high performance vinyl as normal. With some paints, like Sherwin Williams, it is necessary to wipe down the surface with water and dry before applying the vinly. In cold weather it may be necessary to heat the surface with a heat gun in order to make the adhesive have more tack. We apply all vinyl dry.
Hope this helps.
-------------------- Chapman Sign Studio Temple, Texas chapmanstudio@sbcglobal.net Posts: 6306 | From: Temple, Texas, USA | Registered: Nov 1998
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posted
I have been using the method Ray describes because I read about it here several years ago. It has never failed me. I especially like it because I don't have to mess with oil based paints, they make my skin crawl, literally, for several days after I use them.
-------------------- Patrick Sweeney Terre Haute, Indiana Highline Signs Posts: 40 | From: Terre Haute, IN | Registered: Aug 2003
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posted
I've been experimenting with acrylics too. I have found that the roller cover makes a big difference. Use a good velour or mohair cover so the nap dosn't lay down and create a pattern in the paint. I still like oil base better.
-------------------- John Arnott El Cajon CA 619 596-9989 signgraphics1@aol.com http://www.signgraphics1.com Posts: 1443 | From: El Cajon CA usa | Registered: Dec 1998
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posted
Actually we don't use too much MDO anymore, but when we did, I used procedures similar to Ray's accept I use Bondo for any voids and I coat all edges with Marine grade epoxy first, then acrylic primer, then give 2 coats of 100% acrylic house paint.
The other difference is I don't sand anything other than the edges -- rounding the sharp edge and sanding the epoxy prior to priming.
I use and reuse 1/4" nap rollers and find that by cleaning and reusing them time and again, they actually lay out a smoother profile. When I'm done rolling I take them off the frame and throw them in a bucket of water. When I'm ready to use them again I wash and rinse them and sling the excess moisture out of them with a brush and roller slinger.
If there are any snobs on any of the coats, I take a 12" drywall taping trowel and scrape them off. A quick dusting with an air chuck and away you go.
Like Ray, I'll say that you can play too much with the paint and cause it to have too much of an orange peel which will give you fits when you go to put down vinyl. You can add retarder to help out, but I don't like thinning with too much water.
Also I prefer a semi-gloss or satin sheen, because gloss acrylic paints are hard to handle and tape on.
Currently I have been using Nova Paints which are the Cadillac of acrylics with many bright colors that cover well. They are buttery and letter nice with some of the natural/synthetic mix lettering brushes. I have been rolling catalyzed urethane auto clear on top of the Nova Paints almost within an hour without any lift up or smears. You might be able to spray such a clear over urethane lettering paints, but they can't take the pressure of the roller like the acrylics can.
[ March 30, 2010, 06:00 PM: Message edited by: Bill Diaz ]
-------------------- Bill Diaz Diaz Sign Art Pontiac IL www.diazsignart.com Posts: 2107 | From: Pontiac, IL | Registered: Dec 2001
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After rolling the paint we put the roller and cover in a clear plastic bag and secure it with a twist tie. The color is marked on the handle of the roller. The paint will stay moist for weeks and can be reused over and over.
-------------------- Chapman Sign Studio Temple, Texas chapmanstudio@sbcglobal.net Posts: 6306 | From: Temple, Texas, USA | Registered: Nov 1998
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Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity. — Charles Mingus Posts: 6714 | From: Mendocino, CA. USA | Registered: Nov 1998
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posted
Standard operating procedure for white MDO signs here...
1: Cut to shape and seal edges with Bondo to fill voids.
2: Two coats of Kilz general purpose primer/sealer rolled on with foam roller and smoothed by dragging a 4 inch foam brush over it.
3: Two coats of Benjamin Moore (C112 01) White Porch & Floor paint, again foam rolled and foam brush dragged. It's urethane reinforced alkyd and has both a hard finish and nice sheen when your done. Takes the paints or vinyls nicely.
All available at the local hardware store. Rapid
-------------------- Ray Rheaume Rapidfire Design 543 Brushwood Road North Haverhill, NH 03774 rapidfiredesign@hotmail.com 603-787-6803
I like my paint shaken, not stirred. Posts: 5648 | From: North Haverhill, New Hampshire | Registered: Apr 2003
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