Finished a maple table top with stain-BLO-Varnish, looked like crap.
So I set it aside for about 3 months to think about it. SWMBO
motivated me by mentioning trash pickup day was Friday.

I attempted to fix it thusly:
ROS with 80 grit to get to bare wood
ROS 120 grit
ROS 220 grit
wiped down top with damp rag to raise grain
let sit for several hours
ROS 220 grit to remove fuzz
applied water based stain
let sit overnight
applied 50/50 mix of Olympic varnish and mineral spirits with a China
bristle brush
let sit for 12 hours

At this point everything looks/feels good, a few spots where the finish
is thin but pretty good.

Apply second coat of varnish/mineral spirits mix. A few hours later
the finish develops tiny tits or bubbles not brush marks. I recite
George Carlin's 'seven words' and exit garage.

I use 00 steel wool to knock off most of the finish after waiting 36
hours from application of second coat. Apply another coat of 50/50
varnish and things don't look good.

I come upstairs and fire up the 'puter to ask for guidance from the
wreck.

My three theories based on SWAG calculations:
1 Didn't let first coat dry enough - 12 hours and surface had no tacky
spots
2 BLO was still present and screwing up the varnish - unlikely 1st
coat was OK
3 Idiot 'cleaned' the brush with 'rapid brush cleaner' not MS between
coats

Any ideas?

"RayV" wrote in message
oups.com...
Finished a maple table top with stain-BLO-Varnish, looked like crap.
So I set it aside for about 3 months to think about it. SWMBO
motivated me by mentioning trash pickup day was Friday.

I attempted to fix it thusly:
ROS with 80 grit to get to bare wood
ROS 120 grit
ROS 220 grit
wiped down top with damp rag to raise grain
let sit for several hours
ROS 220 grit to remove fuzz
applied water based stain
let sit overnight
applied 50/50 mix of Olympic varnish and mineral spirits with a China
bristle brush
let sit for 12 hours

At this point everything looks/feels good, a few spots where the finish
is thin but pretty good.

Apply second coat of varnish/mineral spirits mix. A few hours later
the finish develops tiny tits or bubbles not brush marks. I recite
George Carlin's 'seven words' and exit garage.

I use 00 steel wool to knock off most of the finish after waiting 36
hours from application of second coat. Apply another coat of 50/50
varnish and things don't look good.

I come upstairs and fire up the 'puter to ask for guidance from the
wreck.

My three theories based on SWAG calculations:
1 Didn't let first coat dry enough - 12 hours and surface had no tacky
spots
2 BLO was still present and screwing up the varnish - unlikely 1st
coat was OK
3 Idiot 'cleaned' the brush with 'rapid brush cleaner' not MS between
coats

Any ideas?

1. Going from 120 to 220 is too big of a jump. You left out 150 and 180
however I doubt that is what is causing your bubbles.

2. I have learned to not use a bristle brush to apply varnish. Typically I
try to use a rag or I use the better quality "foam" brushes made by Wooster.
This keeps the bubbles out for me.

3. Try thinning the varnish down more.

Suggestion:

Loose the brush. Personally like a thinned varnish but IMO 50/50 is a bit
much. Maybe 3:1.

IME application with a rag allows me to put less finish on per coat. This
makes it just about impossible to have a drip and it ensures that any dust
that settles into the finish sits up on top of the finish and is (more)
easily de-nibbed between coats.

The downside is that it takes more coats and more time to get a significant
build to a finish.


Apply second coat of varnish/mineral spirits mix. A few hours later
the finish develops tiny tits or bubbles not brush marks.

Was there a temperature change? I made the dreadful mistake of bringing a
fresly finished oak pies into the warm house to cure... air in the pores
expanded. But I would have expected your first coat to seal the pores.

I use 00 steel wool to knock off most of the finish after waiting 36
hours from application of second coat. Apply another coat of 50/50
varnish and things don't look good.

is the problem more bubbles?

My three theories based on SWAG calculations:
1 Didn't let first coat dry enough - 12 hours and surface had no tacky
spots Should be fine

I would think so too.... 12 hours is plenty ay 70 degrees... curing really
slows down at lower temps though.

2 BLO was still present and screwing up the varnish - unlikely 1st
coat was OK

I doubt it, BLO is generally fine under an OB varnish.

3 Idiot 'cleaned' the brush with 'rapid brush cleaner' not MS between
coats

Why even clean the brush? just leave the brush suspended in a jar of thinner
until the next coat (assuming it's not more that a day or three) better
still, apply finish with a small section of an old shirt. The thinner
(quantity applied, not viscosity) the smaller the imperfections.

"RayV" wrote in message
oups.com...
Finished a maple table top with stain-BLO-Varnish, looked like crap.
So I set it aside for about 3 months to think about it. SWMBO
motivated me by mentioning trash pickup day was Friday.

I attempted to fix it thusly:
ROS with 80 grit to get to bare wood
ROS 120 grit
ROS 220 grit
wiped down top with damp rag to raise grain
let sit for several hours
ROS 220 grit to remove fuzz
applied water based stain
let sit overnight
applied 50/50 mix of Olympic varnish and mineral spirits with a China
bristle brush
let sit for 12 hours

At this point everything looks/feels good, a few spots where the finish
is thin but pretty good.

Apply second coat of varnish/mineral spirits mix. A few hours later
the finish develops tiny tits or bubbles not brush marks. I recite
George Carlin's 'seven words' and exit garage.

I use 00 steel wool to knock off most of the finish after waiting 36
hours from application of second coat. Apply another coat of 50/50
varnish and things don't look good.

I come upstairs and fire up the 'puter to ask for guidance from the
wreck.

My three theories based on SWAG calculations:
1 Didn't let first coat dry enough - 12 hours and surface had no tacky
spots
2 BLO was still present and screwing up the varnish - unlikely 1st
coat was OK
3 Idiot 'cleaned' the brush with 'rapid brush cleaner' not MS between
coats

Any ideas?

Dust and other debris is a good chance if you finished it in the shop. When
I varnish, a finish I do like, prior to the last coat of greatly thinned
varnish is a complete wet sanding of the surface with a mineral
sprits/varnish mix. Ratios vary, depending on temperature and humidity.

Dave




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Leon wrote:

Typically I try to use a rag or I use the better quality "foam"
brushes made by Wooster.

I'm sure the folks in my old home town appreciate your support.

Lew