Painting issue – bubbling on a second coat?!?! Not sure why
I have had some great success with the tips I have learned here, but alas, there is always something more to learn.
I am now painting my upstairs hallway. It is quite a simply job overall. I sanded the ceiling lightly and painted it with a single coat of celing paint that I have used for all the other three rooms (with great success I may add). But today when I went back to paint (a full 24 hours after), on the first stroke of paint, there were major blistering and bubbles – dozens and dozens of them! I know they are bubbles because as I poked them, they moved around! What could possibly cause this? Again, I have done 3 other ceilings with no problems using the same kind of paint and in fact this tin is 1/2 used from another ceiling I completed. But I am bewildered why?!
I stirred the paint before use, so I can’t figure it out. I am going to have to let it dry and sand it all over tomorrow and start again, but I would like to know what caused it so I don’t have it happen again. Thanks in advance.
But you didn't wipe before the first coat?
Probably oil paint, possibly applied at one point to cover some water stains.
Sounds like there is something on the surface that is preventing
good adherence. That could be a previous paint coat, as Dan points out, but could also be just about anything oily. You could try priming the areas with a good sealer (e.g., BIN) before attempting to repair and paint.
Understand that as any paint dries it changes shape slightly, either expanding or contracting. If the adhesion to the previous coat is sufficient then this change in shape doesn't cause a problem, but with insufficient adhesion there can be problems.
In your case likely the first coat was poorly adhered to the original paint. Adhesion is fairly good as the paint is drying, but weakens once it dries, then improves over the next few days as the paint cures. So the first coat went on OK, but you likely applied the second coat just at the time when adhesion of the first was at it's poorest, and the stress of the second coat caused the first coat to separate. This effect was amplified since moisture from the second coat worked through the uncured first coat and further weakened the adhesion of the first coat.
So the two things you can do are 1) use a primer that will improve adhesion, and 2) wait longer (perhaps 3 days) between coats, so that the first coat will be better cured.
Yes, I think it is a combination of things. The paint underneath - which the previous owner had done - was an oil based paint and he did a lackluster job (I know I shouldn't criticise because I am a novice, but really, it wasn't very good).
So here are the 2 issues I am now stuck with.
1) The rest of the ceiling has one coat of latex on it. I haven't tried putting another coat on it yet for fear of the same thing happening. So I am willing to wait a few days and see if it cures as Dan suggested above.
2) The real problem - where the paint blistered and bubbled (about 1.5 feet by 1 foot area) has no paint on it at all - and looks really bad because the rest of the ceiling has 1 coat of paint on it. So it looks like an uneven square as been cut out of the ceiling. I tried to patch it with CGC compound around the edges and feather it out to make it look smooth, but alas, working on the ceiling isn't the ideal way for my body to contort to do this. So I tried putting Latex primer on the 1.5 X 1 foot area last night. It doesn't look good. So I am trying to figure out a way to fix it.
You migt be able to mix some drywall compound and paint together and roll it on. I would experiment on a small area where there were problems before to test the outcome. The combination may camouflage the existing surface enough to hide it after repainting the ceiling.