Varnish/Urethane and Thinning

[Bryan Hansel]

I'm refinishing the bottom of my Siskiwit Prototype before it goes to its new home in Florida and I want to avoid some of the problems that I've had with Helmsman Spar Urethanein the past.

My problems are that I tend to get some runs and drips. My gut tells me that the varnish is going on to thick, because it seems so much harder to apply vs. Captians or Flagship. I'm applying in 65 to 70 degree temps and down to 50s at night.

First, is thinning it going to solve my problem? Or what is my problem? Second, if thinning will help, what do I use and how much?

Thanks.

[Glen Smith]

I have never tried that particular varnish. I use mostly Epifanes and straight out of the can it is too thick and will run and sag. I add the manufacturer's recommended thinner until I find the brush glides easily along the surface rather than dragging as when it is too thick. That is usually around 10% to 15%.

Is there no recommended thinner marked on the can or perhaps on the manufacturer's website????? :rolling eyes

Edited: I found this on their website:

Clean Up: For easy clean-up use mineral spirits or paint thinner.

I imagine the same products can be used for thinning purposes. Don't forget to test it on something else first.

[ealger]

I've used several varnishes for different projects with mixed success when it comes to runs and drips. However, on my canoes I've only used HMG varnish with their recommended thinner adding 10%. I've never had problems with HMG running or sagging. I apply with 3" foam brushes. Also HMG K type is a nice flat varnish I like for the inside to avoid glare. HMG is expensive but I feel worth the cost.
Ed...

PS. I think the GreenValley varnish method is super:
http://www.greenval.com/FAQvarnishing.html

[Dell Littlefield]

I thinned the Helmsman about 10% with mineral spirits and that helped on the sags and runs. I had very poor luck with the Helmsman standing up to direct sunlight. I made a mailbox with the leftover strips about 3 years ago. The Helmsman varnish had to be replaced after less than 6 months. I have had much better luck with the Zspar.

[Rick]

Bryan, a thinner varnish should go on in thinner coats because it'll be easier to brush out. There'll be less weight pulling down on the thinner layer of liquid varnish and it should run and sag less.

The Defthane varnish I'm using now is thinner than the Interlux Schooner I used previously, and runs less, so if I had known that thinning the Interlux would have resulted in less runs, I would have bought their special 333 Brushing Liquid to thin the varnish with (more $$$ for an already expensive varnish).

[Bryan Hansel]

Thanks, everyone. It sounds like 10% with mineral spirits. That Green val article is gold.