Help Varnishing Problem

[Blackadder]

Hi,

I'm varnishing this wooden chair and hit a big problem.

What happened was this is a revarnishing job. I sanded the chair back. Applied the first varnish- and all was really sweet. It was perfect.

So I applied the 2nd varnish several days later. The problem was that I was doing it at night. Then my good friend unexpectedly showed up with DVD and a couple of drinks and started to chat with me. So I rushed the varnishing job - sploshed on the varnish and hurried it up.

Two days later- I took the chair and put it out in the sun. There were several streak marks in several areas caused by the application of too much varnish. These marks couldn't be seen if you looked at the chair front on.

I took out a light sand paper and started sanding back. After a vigorous application- they rubbed off like dead old skin- they started peeling off.

I stopped... oh crap. What have I done? ARGHHHH...!!!!!!

My question is- should I carry on sanding back the thick streaks of varnish? When I sand it back- the areas where the varnish isn't so thick- gets collateral sand back too- and ends up bare wood.

[dadiOH]

Yes, after it dries. Which could be several weeks depending on how thick it is. If you don't want to wait you can cut it off with a razor blade, let dry at least overnight, sand lightly until smooth and feathered, recoat. ________________

Learn to sand.

[Dave W]

Dadioh has it right on! A sharp card scraper can also be used to remove the semi-set varnish as well. To prevent sags or curtains, use a little Penatrol and keep the brush relatively dry.

[Blackadder]

Thanks for your replies.

I think another mistake I made was- the brush had some water in it. After the first varnish I had washed it in turp then kept it in water to keep it moist. When I pulled it out to use it the 2nd time around- there were still some water trapped inside the brush. I cleaned it out with a rag- then hammered the brush to push out the remaining water. But there might have been a little bit of water still left inside the brush.

[dadiOH]

1. Use natural bristle brushes with varnish (or any oil base coating).
2. Don't use natural bristle brushes with water. After washing, shake out water, shape bristles and let dry by hanging from handle.
3. Don't use water-wet brushes with any oil base finish; let them dry first (see #2)
4. Don't "hammer" *any* brush. I have no idea what "hammering a brush" is but it can't be good.
5. Duh...

[Blackadder]

Yeah, duh... I know ;)

It's my first time doing a major varnishing job like this ... but I guess u figured that out already :)

Thanks for the help.

Cheers!!!

[Ron Magen]

Does the phrase, 'You reap what you sew' ring any bells??

Mahogany 'Brightwork' is beautiful to behold. None the less a lot of boat owners have a love-hate relationship with it. a} it requires regular 'inspection' & maintenance to keep that look, and b}it takes a bit of patience for delivery of the finished product. 'B' is what makes Joanne really grind her teeth when she wants something finished . . . from me.

When I saw your question the answer jumped right into my head . . . too much varnish and a slight 'curtain'. The 'corrective action' would have been to let it thoroughly cure for several days to a week. THEN sand CAREFULLY with fine grit. At this point, sight unseen, I'd say to scrape back any 'lumps', then sand everything to an even surface.

My experience has been to use decent Varnish {I am NOT going to start a 'bar fight' by saying , ' the BEST is . . .' }good technique, and PATIENCE. Think 'long term'. I know this is going to sound like heresy, but I typically use an inexpensive foam brush and get excellent results.

1} PREP surface - this may be the most important step. Fill the grain if necessary & sand to no more then about 120. Brush, vacuum, wipe with cloth dampened with solvent.

2}Apply first coat - diluted 50-50 - well 'brushed out'. Let cure 24-hours

3}Apply second coat {NO SANDING} - diluted 25 percent - well brushed out. Cure 24-hours.

4} LIGHTLY, GENTLY sand with 220, wipe with clean cloth dampened with solvent and apply third coat - diluted just enough to get an even 'stroke'. Let cure for 24-hours. {Remember what I said about Patience ?}

5} through ???? Following the same schedule, now 'flow on' undiluted coats & sand with ever increasing fineness {320, 400, 600, . .}. A typical 'Bristol Finish' *begins* at 6 coats.

It only takes a few minutes and a small amount of material for a 'well brushed out' coat. Only a bit more for a 'flowed' coat. The patience to let it fully cure is the tough part.

Regards & Good Luck, Ron Magen Backyard Boatshop

PS - there are variations on Prep & Material, but this is the 'Basic Concept'.

"Blackadder" wrote > Hi,

SNIP

[Blackadder]

Hello Ron,

I think the phrase is "You reap what you sow". :)

Yeah, things were going smoothly. Prep was good. First coat went well. I rushed the second coat due to reasons explained in my post.

Thanks for your detailed explanation. I'll try and be more patient next time. I think when my friend had shown up- I should have simply stopped varnishing. Then started it the next day. Rushing it was a bad idea. Sanding back the thick varnish was my 2nd bad idea.

[Ron Magen]

'Hindsight is ALWAYS 20-20', believe me . . . I KNOW from experience !!

'Patience' is probably the toughest part of boatbuilding, but then again I'm a sailor {as in 'Sailboat' as opposed to 'Powerboat'}so maybe I've 'mellowed out'.

Next time, tell your buddy to go sit down, have a 'tinny', watch the 'tube' {or you - as long as he doesn't open his mouth}, and concentrate on finishing the coat you are applying.

Regards & Good Luck, R>

SNIP

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