Correct method of varnish application.

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goanywhere
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Joined: Wed Mar 30, 2011 7:20 am
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Correct method of varnish application.

Post by goanywhere » Thu Dec 08, 2011 6:32 pm

I am noticing that there are some patches where the marine varnish I applied is flaking off. I may not have prepared the surface properly. I did sand it to a satin finish, but I didn't wash it down with anything prior to varnish application.

What do folks here recommend for the best varnish application? How many coats do you recommend?

(I am using Norglass Poly Clear.)
My psychologist reckons I need lots of fishin' therapy!

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rodot
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Re: Correct method of varnish application.

Post by rodot » Fri Dec 09, 2011 3:04 am

It's a shame to put in all the hard work in building the boat and then have it spoilt by a bit of varnish. I know nothing about this subject, but I would have assumed that sanding the surface should have been sufficient preparation for varnish. Perhaps it would be best to contact the technical department of the varnish manufacturer and seek thier advice. Guess you've got a bit more sanding to do. :cry:

Roger
Okwata LC,
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john the pom
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Re: Correct method of varnish application.

Post by john the pom » Fri Dec 09, 2011 5:45 am

After you've sanded it ALL back (and you thought you had finished with all that) Good clean over with metho should remove any oily residue whether or not there might be some.
Try straining the varnish first through a pair of pantyhose (not ones that you're currently wearing) a few times. Even a new tin of varnish might have been stood in stock for years and begun to crystalise... Stir, never shake!
I used Bondall Monocell Gold marine varnish in a satin finish and have had no problems. Available from Bunnings. Great price too at about $15. I just do three coats, knowing that next year I'll probably put another one on and the following.......... I think satin finishes don't show as many scratches and imperfections.
On my Laker I just used a general purpose exterior gloss varnish. No problems with that either.
It's getting harder to find a "varnish" nowadays that is not water based :shock:
Cheers John.

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Correct method of varnish application.

Post by goanywhere » Fri Dec 09, 2011 4:25 pm

I contacted the manufacturer of the product I used - Norglass Paints. They recommend a 2 pack product to give the longest lasting and toughest finish. The good news is that I don't have to totally strip all of the varnish I applied, just give it a medium sand to remove all the flaky bits and key the rest. I will wipe it all down with acetone before applying the new stuff, and that should fix it. I'll wait until after summer is done before doing it, it's not soo serious and is only affecting a few areas.

Why don't you get good advice in marine stores these days? Another guy in the same store I spoke to said he always advises sanding and cleaning the epoxy with acetone before applying any varnish. Aparently epoxy does tend to leave a waxy residue (especially if applied in cooler weather) that can affect varnish adhesion. :x

I was going to apply another couple of coats at the end of the season anyway, so it's not much more effort. :D
My psychologist reckons I need lots of fishin' therapy!

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