Robert,

Thanks! for the excellent advice.

Appears the problem was self induced - really hate it when that happens.

However, now I know better and will no longer use mineral spirits as a wide
down aid.

What is the preferred method for spraying lacquer from a rattle can?

I understand to not apply heavy coats - just not sure if maintaining a wet
edge when spraying is considered a heavy application.

There are no doubt degrees of wet edge - and will have to learn the best
application method in the school of hard knocks.

Thanks again for the benefit of your experiences.

Regards,

Doug


wrote in message
...
On Jan 20, 3:23 pm, "doug" wrote:

As you previously suggested when I inquired about finish recommendations
for
red oak, used the shellac sanding sealer and rattle can semi-gloss
solvent
based lacquer, brand is Watco.

Now you're going. Watco rattle can solvent is a good quality finish,
and is now made by Rustoleum. I don't know of a Rustoleum product
that isn't pretty good to excellent. Good choice.

The surface anomalies appear to be very small circular areas -
likely very
small bubbles (?).

Since rattle can lacquers don't need to be shaken, we can rule out
infusion of bubbles from the can.

Given the facts you described, I would GUESS, - key word there - that
the bubbles were due to the mineral spirits continuing to "outgas' or
dry under the lacquer. The lacquer has a much higher
VOC content and will skin over rapidly.

Any remaining heavier oils (lower VOC) that is in the wood will
continue to outgas, but at a slower rate. The gas is trapped under
the drying skin, and then you have bubbles since the gas has no where
to go but out. Leetle bitty ones.

But the gas has to go out, right? I won't stay trapped, that's for
sure. And since mineral spirits are much lower VOCs than the one
found in lacquer, you may have the culprit.

The surface is clean to the eye and touch before spraying and the work
area,
while not a clean room, is free of loose particulates.

That would support my best guess above.

If I use lacquer thinner to wipe the surface of a solvent based lacquer -
will that tend to remove / soften the previous lacquer coat?

NO! You will have a mess you cannot fix unless you are ready to belt
sand your project! This is what I would do (YMMV, right?):

1) sand the surfaces in question as smooth as possible

2) Brush the surfaces as clean as possible, then blow them off with
your compressor and and nozzle.

3) Clean the surfaces with naptha. It isn't as hot as lacquer
thinner, so if you are fast with just enough naptha to get your tack
cloth damp, you can get your surface clean with no surface melting

4) Apply a coat of lacquer (not sanding sealer) and allow to dry 24
hours. Remember, you are repairing a damaged finish, not starting a
new one. Be patient.

5) Sand this coat as smooth as possible. Still see the bubbles?
Sand, clean, and repeat #4. Don't forget to wait the 24 hours. This
allows the resins to harden enough to make your sanding cleaner with
less tiny scratches, and help prevent "pilling"

6) When you are smooth, apply another coat or two to get the desired
finish and call it a day

Have not previously sprayed lacquer wood finishes - although have done
airbrush painting of models with enamel and lacquer and painted a full
size
motorcycle with catalyzed urethane.

Same principles. You are probably just a little off track in your
prep.

Surface appeared dry - however did not wait a min. half hour before
spraying - although at approx. 20% humidity the mineral spirits appeared
to
dry quickly.

Me and mineral spirits have a frustrating, checkered past. In some
cases, it can prevent good adhesion and even sabotage finishes that is
is actually used to thin. I will use it as a thinner or a brush
cleaner, but nothing else.

It is thin enough to get surprising penetration into wood, but it
doesn't wick away and evaporate quickly leaving you to guess what you
will have under your finish when using it as a cleaner.

And if you have uneven amounts on your cleaning rag (like a wet corner
or side) you can even see your cleaning stroke marks when dying wood
or with some clear finishes. This is particularly true when
refinishing. Imagine my horror (nothing less...) when I saw this
happen on an antique mahogany door I refinished.

I was so embarrassed I stripped it, dyed it, and refinished it again
on my nickel.

Good luck, Doug. Let us know how you come out.

Robert