bubbles in exterior paint

topic posted Thu, April 28, 2011 - 7:59 AM by  Chili
there are numberous bubbles in the paint on an exterior wall of my house. the painter who did the original job came back, sanded them off, primed and painted again. they bubbled again. now it's my turn to fix it. I live in a foggy area so sometimes it is damp out and I imagine this may be helping create the problem. the wall is not damp though, and the wood of the siding does not touch the ground anywhere.

any suggestions for tricks to a smooth paint job? I'm tired of looking at it near the front door every day!
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  • It would appear that that paint does not like that particular wood or else it's the wood that doesn't like the paint all that much. So what we're looking at is finding a paint formula that's compatible with the surface you lay it down on.
    I hesitate to say the words total paint removal down to raw wood and start over but that may be the one long lasting option.
  • You say bubbles, how large are they, or is the paint just peeling ? Also do you know if it is oil or latex paint, and primer ?
    • It's a matter of using a paint that gives to bonding with the surface... one that will not lift away due chemistry, ambient conditions. Something like an oily paint that will be drawn up by the dry pores of the wood while it cures. And then the primer coat may be the culprit. So many variables.
  • yeah lots of variables I guess -- the painter had sanded down to bare wood before repainting the bubbles the first time -- there isn't any peeling paint, unless I crack into the bubbles and peel it off myself - and used a primer (not oil-based) with the latex exterior paint (Benjamin Moore). I think I should probably sand down to bare wood again, prime with an oil-based primer this time, then re-paint with the same latex exterior paint again. that's the only thing I can think of that would be different. somehow I think that there may be a non-sticking layer in there (house built in 1940'2 so many layers of paint that I had nothing to do with).
    • Unsu...
      I don't think you can get oil exterior any more. Moore Paints are the number one choice for me.
      I'm wondering of the wood was wet or contaminated with something god awful.

      I'd call Moore and see if they have anything to say
    • Did he wash the walls and how long did he wait before painting the bare wood? Sounds like a problem with the primer used. Also, you have to wait a sufficient amount of time after applying the primer-sealer to the wood before putting the regular exterior paint on.
      • There is an acrylic primer made by zinsser called peel-stop ( imaginative name or what?) it's very very good but I don't know if its available in the US. Perhaps you can find a US retailer or similar product.
        • Unsu...
          I believe peel stop is intended to cement down loose flaking and cracked paint. So far as I know it wont prep a surface for paint.
          • No Cliff, Zinsser peel stop is an acrylic based primer suitable for stabilising surfaces on exterior walls before painting with standard undercoat and top coat paints. The website has product information sheets available. I have used their products and they work.
            • When I saw this on a 1992 This Old House, I made a mental note to remember a method they showed for quickly striping paint off an old colonial clapboard. I plan to use this if I ever have to do another one of those. They used a router-looking powertool with a sort of flat blade that protruded about 1/16" and that automatically shaved off the crap old paint layers quickly & neatly down to naked wood in a jiffy.

              Another trick to get paint to stick is to find out what solvent is used to thin the kind of paint you happen to be using. For example wether it's water, mineral spirits, turpentine,...
              First leave out using the primer.
              Then paint the raw surface with that thinner. Then let it soak in a bit. Then paint over the thinner coat with the actual paint coats. The thinner will promote and accelerate surface bonding adhesion while the coatings cure to dryness. This makes for just a tiny bit more solvency on a molecular level at the materials interface.
              • Unsu...
                I use a Porter Cable Paint Grinder
                Works great on old hardened off oil. It has speed control on a dial not the trigger so you can set it and forget it. Ya gotta run it slow on vinyl or ya get goo and glue and when it cooks off the grinding disk is gone. I've tried soaking 'em in paint stripper. IT sort of works but cooked off paint is tough stuff.
                • that device on TV was setup something like the porter machine but I remember it as having a rotating cutting blade rather than a E.Z.-clog grind disc. And the chips of old surface would be flyin and the shavings of old paint would come durling off the blade. It was a sight.
                  It could have been purpose-built by a manufacturer, or more likely was a home-made modification of a router with welded on parts to allow riding it into corners and a special custom machined 4" cutting blade modeled on the way a lawnmower blade works, but on a small scale.
                  • This is the maximum depth. Additional responses will not be threaded.
                    Briggi, I think the tool you're talking about is called the Paint Shaver Pro. I don't seem to be able to find a web site that sells it. Maybe Benjamin Moore stores.

                      • that paintshaver looks like it could kick some serious crappy old paint ass. Now just imagine a unit that looks like Cliff's Porter-Cable, with two handles and a vertical motor, not unlike a router, but having a blade configuration like the paint shaver's instead of a grind disc. I like the two side handle concept for the added precision control.
                        I've thought about it and I could adapt a router or even the PorterCable to take such a blade, but machining a proper blade to fit might take some expertise. Perhaps a spare paintshaver blade adapted for mounting on a modified router would do it up nice without biting the $600 PaintshaverPro pricetag.

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