Varnish tricks

[patfly]

I started doing the varnish work on my teardrop. This is really hard to get right.

Some of you boat building types must have more info and skills than I do.

I have a couple of questions, first how can I preserve my varnish. I was so surprised to see how much skin formed on the surface of the unused varnish in the can. After a short while, a day or two. Can that be prevented or reclaimed f or use?  Second, on one area, I didn’t do very well on my prep work before my first coat of varnish. Lots of tiny pin holes. What is the remedy? Will it get better with subsequent coats, or do I sand it all off?

Thanks, what a great project!

[tomtnt]

do you have any pictures?  which varnish are you using

[CWStevens]

I *highly* recommend the stop-loss bags from CLC.  https://www.clcboats.com/shop/products/boat-building-supplies-epoxy-fiberglass-plywood/marine-paint-varnish/clc-stoploss-kit.html

 

As far as pin-holes go – it sounds like you’re describing fish-eyes.  These are caused by some sort of contamination on the surface of your project.  I’ve heard a number of things will contaminate the varnish, so it’s best to avoid it altogether.

Anecdotally, I’ve heard the following things are known to cause fish-eyes:

1. Any kind of oil mist in the project area, lawnmowers, air fresheners, candles, etc.
2. Pollen, localized grass-cutting, etc.
3. Fabric softeners and/or dryer sheets, especially when used on wipe-down rags.
4. Some covers may have PVC out-gassing issues.
5. Contamination from fingers, hands, etc.  (Ooo, it looks like glass!  Is it wet?  Lemme touch it!)

You get the idea…  TRUST NOTHING.

What can you do about it?  Vigorously scuffing (matte finish) the most egregious violations.  Followed by:

1. A wipe-down with denatured alcohol, using a clean cotton t-shirt material rag.
2. A wipe-down with blue windex, using another clean cotton t-shirt material rag.  (ONLY BLUE WINDEX.)
3. A wipe-down with denatured alcohol, using a third clean cotton t-shirt material rag.

And waste very little time after you’ve completed the three wipe-downs.

I was successfully able to launder my t-shirt rags using unscented dye-free liquid laundry detergent, and a healthy dose of bleach.  And remember, don’t use laundry sheets in the dryer!

Good luck!

 

 

[Bill]

I agree with CW in cleaning the surface with alcohol and not only for the varnish but for the coats of epoxy that go down before the varnish. I built mine during the last winter in my garage heated by an unvented gas heater. All went well until the last coat of epoxy when it was below freezing and the heater was running a lot. The finished last coat when hard was showing signs of not adhering and could be peeled off in places, none of this was the case with previous coats. I finally called the supplier of the epoxy and he at first was stumped. Finally we decided it was the unvented heater leaving a slight film of soot or oil on the epoxy surface. After sanding down the last epoxy coat to the previous one we did the folling. We heated the garage to a mid 70 range for half a day and then opened all the doors and windows to flush out the contaminated air quickly and quickly closed up leaving the gas heater off but a small electric heater on. We then washed down the whole surface with alcohol and applied the last coat of epoxy, problem solved.
Some tricks with varnish. You can try and cut down on the amount of oxygen that is in a used can of varnish by keeping the remaining varnish in a smaller container with as little air as possible, or you can buy a can of inert gas to use to replace all of the oxygenated air in the partially used varnish can. Lastly you can just cut out the thin skin layer in the varnish can and throw it away and then use the recommended thinner for the varnish to return to a desired viscosity. Trick I used for appying varnish. I thinned the varnish just enough to flow better when using a brush but here is how I applied it. I rolled out a small enough area to still be able to smooth it out with a brush before it got too firm then returned with the roller to do the next adacent area. The result leaves a glass like finish with no apparent runs. You can also use Penetrol as an additive to the varnish to make it flow better but do a test to make sure it’s comparable with the oil base varnish you are using. Hope this helps.

[Author]

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