Spar Varnish Application: Horizontal or Vertical

Repete

Repete

Sunfish1909
I am applying my four coats of spar varnish to all of my wood parts now. I have stripped and sanded, doweled my rudder with treaded rods, and have done two of the four coats so far.
I laid my wide boards horizontal, the rudder and dagger, and have hung my tiller and the extension. I applied varnish to one side at a time for the horizontal, wide boards and covered all surfaces of the hanging pieces. Here is where the question starts. I carefully used a tack cloth to all the wood before applying varnish. I also used the tack cloth after the in-between sandings of the varnish to get a tooth for the next coat. What I am noticing are several, almost to hard to see, bubbles appearing on the horizontal curing varnish and none on the vertical curing varnish. I only stirred the varnish and slowy applied it as to not create bubbles, but they have appeared on the horizontal pieces. They look like a grain of salt about three inches on centers, but under a magnifying glass they really are a ruptured air bubble.

Should I be hanging all the pieces when applying varnish?
 
repete, I hope that you thinned the first coat to about 50%, and the second 25%, the third 15%...
It is a really common mistake to just apply the varnish right out of the can, but this can lead to early peeling and cracking of the finish. Your bubble problem may be a result of the brush. Get a good natural badger haired brush, 1 1/2 to 2 1/2" wide. I like to brush the varnish on across the grain, then tip the coat of with a set of very light strokes, with the grain.
 
Nikobrogna,

Ugh...............you are right. I did not do the thinning. What would be the life expectancy of my finish.........two or three seasons? I am two coats along. I could strip back and thin out the proper way or just finish out and do it all again in when it fails (prematurely). What shall I do. I am using a Petit Captains Varnish.
 
repete,
If I were you, I would just continue, and put another coat or two on the parts. If it peels, it peels, and you can refinish then, but this shouldn't happen for quite a few seasons. The finish will last even longer if a fresh coat is applied each season or so.
happy sailing,
-Nick
 
Nick,

Since I had only placed two coats on one side of my dagger, but both sides of my rudder, I stripped back last evening. I used a citrus strip product that is very potent, but very easy on the grains of the wood. I will rinse out this evening with thinner and let all the wood dry out for a light sanding next week. I am in no rush up here in Michigan. Haste makes waste so I lost a little varnish. I would rather do it right.

Thanks Nick.
 
If you're going through all this prep work, you might as well do it right. See my previous posts regarding what I believe is a far superior product. Where did you find a product known as spar varnish? I thought that went out sometime in the 70s. Polyurethane is known to be far superior to spar varnish, and I'm asserting the 2 part urethane is even more superior to one part polyurethane than one part polyurethane is to spar varnish!
 
Al Court,
I have used the Petit brand Z-Spar #2015 Flagship Premium Exterior Marine Varnish. I have read some of your postings and was interested in the aviation grade finishes. I am operating my shop on a shoe-string budget and am getting a workout every so many seasons stripping and sanding. I purchased my boat from a older sunfish racer and iceboater that had great regard for the stuff in this can. I know there are other methods. I appreciate your conviction to do the right thing. What two part urethane have you used? Thanks.
 
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