lyonkster
Well-known member
Having some issues with bubbles forming in the waterbased polyurethane coating I'm applying, and could use some suggestions.
I'm using this product, and my plan was to apply two coats at about 0.006" thickness (they recommend no more than 0.010" per coat).
But after applying the recommended epoxy primer and the first coat of poly (which I rolled on using their recommended roller, with the recommended two direction rolling action), I noticed lots of bubbles forming:
So I stopped, and will sand the finish after it cures and will apply another coat, but I'd like to avoid having the bubbles again.
I talked to the manufacturer of the poly, and they said the bubbles are most likely due to concrete outgassing, and that the second coat should have much fewer bubbles since most of the surface is now sealed by the first coat of poly. Sort of makes sense to me, although I am not convinced that the existing bubbles do not form tunnels which will then lead to bubbles in the next coat.
The other line of reasoning is that the bubbles are formed from the application technique - either too thick a coating, too much back and forth rolling, etc (although both were done per manufacturer's recommendations). From what I read, lots of folks seem to recommend a t-bar applicator rather than a roller, something like this. The idea seems to be that the coat thickness will be thinner, and there won't be bubbles introduced by rolling, since this applicator pushes the poly around rather than rolls it.
I asked the manufacturer of my poly about this type of applicator, and he said he never heard of it. I talked to the manufacturer of the roller, and he said it should work fine even with thick coatings, like my ~60% solids poly.
Any thoughts on this, and how to proceed with my next coat so that it hopefully becomes my last? Same technique as before, or switch to the t-bar and go thinner (about 0.003")?
I'm using this product, and my plan was to apply two coats at about 0.006" thickness (they recommend no more than 0.010" per coat).
But after applying the recommended epoxy primer and the first coat of poly (which I rolled on using their recommended roller, with the recommended two direction rolling action), I noticed lots of bubbles forming:
So I stopped, and will sand the finish after it cures and will apply another coat, but I'd like to avoid having the bubbles again.
I talked to the manufacturer of the poly, and they said the bubbles are most likely due to concrete outgassing, and that the second coat should have much fewer bubbles since most of the surface is now sealed by the first coat of poly. Sort of makes sense to me, although I am not convinced that the existing bubbles do not form tunnels which will then lead to bubbles in the next coat.
The other line of reasoning is that the bubbles are formed from the application technique - either too thick a coating, too much back and forth rolling, etc (although both were done per manufacturer's recommendations). From what I read, lots of folks seem to recommend a t-bar applicator rather than a roller, something like this. The idea seems to be that the coat thickness will be thinner, and there won't be bubbles introduced by rolling, since this applicator pushes the poly around rather than rolls it.
I asked the manufacturer of my poly about this type of applicator, and he said he never heard of it. I talked to the manufacturer of the roller, and he said it should work fine even with thick coatings, like my ~60% solids poly.
Any thoughts on this, and how to proceed with my next coat so that it hopefully becomes my last? Same technique as before, or switch to the t-bar and go thinner (about 0.003")?
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