We just restained our front door to revive the look. It took 2 days to dry
with the humidity. We then applied two coats of fast-drying polyurethane.
After the 2nd coat, we closed the door with the early evening sun hitting
the door. A few hours later we noticed several bubbles on the door. Not
sure what caused this or best method to fix.
If you read the label on your varnish can it probably said to 'let dry
overnight', 'x number of hours' or similar. Some PU formulations have
solvents that tend soften the partially cured first coat. The fix is
obvious, strip the failed fiinsh, let the stained door dry for a week,
and refinish with a quality spar varnish from a paint store that
knows what they're selling. They can also supply a quality stripping
product as well. Take your time to do it right and the results will be
just fine. HTH
You *were* talking about small, pinhead size bubbles, weren't you? If
yes, above is correct. If not - if they are LARGE bubbles - then it
depends. It is possible that the stain wasn't completely dry and/or
that the top coat was incompatible with it. In that case, remedy is
the same...sand and topcoat.
Thanks to ransley, Joe, and dadiOH. I went to Home Depot and they had a
marine polyurethane. I have sanded the door, wiped it down and letting dry
before applying. This one says four hours but I will let it go eight if
Appreciate all your comments.
IME, with "normal" PU, reasonable RH, and no direct sun, the choice
after the first PU coat is let it dry until surface no longer tacky,
overnight, before next coat. And, if overnight, very gentle fine
or steel-wool between coats. Bubbles? What bubbles?
It's also a Real Good Thing with big pieces like doors to lay them
horizontal before applying. Unless you like saggy bits, or can apply
really light coats (which dry faster anyhow.) YMWV.
You'll let it go 4(8) hours before you do what? If you'll re-read the
instructions I think you'll find that you need to add additional coats
within four hours of each other. If not, you have to wait longer and
sand before applying more coats.
Bubbles are almost an inevitability when applying polyurethane. They
usually "pop" as it dries. I've found that if it's applied when it's
hot and dry the poly dries too fast and the bubbles don't have a
chance to work to the surface and pop.
Hot sun caused it ... the varnish/paint dries to film before solvents
evaporate, solvents are trapped beneath the film. If you have to recoat
it, try to shade it...just sheets of foil, taped somehow to shade the
door, will keep the heat off until it is completely CURED (longer than
"dry"). Also, a good idea not to close it tightly until it is cured, or
at least a couple, three days. Good vacation project :o)
I agree with this. If you stained the door a dark color and have a large
glass in the storm door, it is amazing how hot it can get in the sun. Metal
door that are dark colors can give you a nasty burn. Keep the door open for
a time to keep the sun from hitting it directly.
Keep in mind that while the urethane may be "dry" in four hours, it is not
fully cured for about 2 weeks. Keep it cool until then.
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