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Marine varnish

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Forum topic by jklingel posted 12-26-2017 10:36 PM 836 views 0 times favorited 27 replies Add to Favorites Watch
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jklingel

99 posts in 1354 days


12-26-2017 10:36 PM

I’ve been reading here about “varnish”, and what, exactly, it is…. though it does not appear to be anything EXACTLY. So, a bit confused, I ask this: I am building a kayak which is covered w/ fiberglass and epoxy. I am to now paint it with “varnish”, but it needs to be marine varnish. What are you watercraft builders using over your epoxy, exactly? What brand “varnish”, and are you thinning it to make it “wipe on”? If thinning, with what? Mineral spirits? Thanks. PS: I will ask the kit supplier what they use, but I suspect I can not get their brand up here; that is generally how I find it to be. Thanks. john


27 replies so far

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MrRon

5189 posts in 3440 days


#1 posted 12-27-2017 06:43 PM

It would appear to me that marine varnish is used only on wood, not fiberglass. Marine varnish is an oil base finish (tung oil) that penetrates wood. I don’t think an oil base finish can penetrate fiberglass, especially below the waterline.

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Andre

2195 posts in 2003 days


#2 posted 12-27-2017 06:58 PM

Marine 0r, Spar Varnish can be used on anything, but mainly to protect wood. Every Cedar strip Canoe has a coat or 2 of spar Varnish? Just needs to be roughed up, lightly sanded 180 to 240 grit works fine.

-- Lifting one end of the plank.

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jklingel

99 posts in 1354 days


#3 posted 12-27-2017 07:29 PM

Thanks for the replies. The kit supplier uses Interlux Schooner varnish, which is not sold locally, as I figured. I will try to get their specs sheet and match it as best I can.

View Fred Hargis's profile

Fred Hargis

5171 posts in 2690 days


#4 posted 12-27-2017 07:58 PM

A true marine spar varnish will probably have to be bought at (ta-da) a marine supply place. A good reliable on line source would be Jamestown Distributors.

-- Our village hasn't lost it's idiot, he was elected to congress.

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sras

4941 posts in 3326 days


#5 posted 12-27-2017 08:01 PM

Any of the marine varnishes work well over fiberglass. The marine varnish adds a higher level of UV protection to keep the epoxy from degrading. if you compare specs, you’ll find that – in general – the higher priced marine varnishes offer higher level of UV protection.

-- Steve - Impatience is Expensive

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pontic

637 posts in 805 days


#6 posted 12-27-2017 08:09 PM

Why not a polyester clearcoat from an automotive supplier? They have UV absorbing radicals on their polymer chains.
They are also highly water resistant. However any marine varnish will work that does not contain a natural oil or penetrating oil. Like they said just rough it up and apply it. I’d use a dual action sander to get a swirl sand prep. I’m told by car painters that this gives better retention of the top coat, which is held by mechanical adhesion. Since this an epoxy surface not a wood surface.

-- Illigitimii non carburundum sum

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dbray45

3320 posts in 2973 days


#7 posted 12-27-2017 08:25 PM

A good mix for a marine or spar varnish (varnish is not made any more) is a poly/tung oil mix. It will be oil based.

The premise is that the tung oil keeps the poly soft enough to move with the wood as it expands and contracts with moisture and temperature. The tung oil also protects from UV.

I have used several and also make my own.

-- David in Damascus, MD

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John Smith

1478 posts in 359 days


#8 posted 12-27-2017 09:13 PM

where exactly is “up here” ?? (your location is not in your profile.

here is an article I wrote awhile back on the subject:

https://www.tinboats.net/wp-content/cache/all/varnish-vs-polyurethane//index.html

and one must be careful when someone suggests that a particular finish will protect
your outdoor projects forever – - – oils, by themselves, do not have any UV blockers.
UV inhibitors and blockers is separate ingredient (a very expensive ingredient) that is blended
in the manufacturers process for their products to make them UV stable.
the more expensive the finish, the higher quality it will be. bottom line: you get what you pay for.

.

-- I started out with nothing in life ~ and still have most of it left.

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John Smith

1478 posts in 359 days


#9 posted 12-27-2017 09:31 PM

if you are building a kayak yourself, and you are applying the epoxy
and polyester resin yourself, the products you are using are most likely
not UV tolerant and will quickly break down and degrade if not coated
with something that has massive amounts of UV inhibitors.
if you visit https://www.woodenboat.com/ you can gain a very indepth
education on varnish types and their uses.
again – this is a volatile subject within any woodworking forum.
photos of your project would be most appreciated !!

I personally would use Epifanes Spar Varnish or Petit Captain’s Spar Varnish with their proprietary hardener.

.

I have been following this item on E-Bay. it is a UV Blocker additive for polyester resin.
https://www.ebay.com/i/291224806903?chn=ps
I can not find too much information about it on the interweb and I contacted the seller
and he is only the seller – not the manufacturer and does not have any knowledge of its ingredients.
if it is as good as the label says it is, it would be a good additive for the final fiberglass gelcoat.

.

-- I started out with nothing in life ~ and still have most of it left.

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pontic

637 posts in 805 days


#10 posted 12-28-2017 12:30 AM

Excellent article John. Very informative.

-- Illigitimii non carburundum sum

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Sailsnsaws

11 posts in 1466 days


#11 posted 12-28-2017 01:06 AM

I was going to suggest the same two products as John and I’ve varnished over a lot of epoxy.

View jklingel's profile

jklingel

99 posts in 1354 days


#12 posted 12-28-2017 06:27 AM

Pontic: “However any marine varnish will work that does not contain a natural oil or penetrating oil.” I thought I wanted tung oil. That seems to be advised a lot. ???
John: Sorry about the missing location. I thought I added it after someone else mentioned that. Fairbanks, AK. Too, I started reading your article, and will finish it and read on the link you sent. Thanks much. A brain full of info….
All: The problem with buying Outside (the contiguous States) is shipping. I looked into buying yacht paint several years ago, somewhere back East, and the salesman said the shipping for a gallon was the same as a case; $256. My son came back from Seattle a few months later and I had him bring some. I was told all paints (and I assume varnish) is hazmat and it gets ugly to ship it. I will investigate. Maybe now with Trump, everything is loosened up and SCREW THE ENVIRONMENT! I hope not; we only have one, and are messing with it as is…. not to diverge…. Cheers. john

View Fred Hargis's profile

Fred Hargis

5171 posts in 2690 days


#13 posted 12-28-2017 12:27 PM

Well, hazmat goes a little beyond environment issues…there’s also safety concerns involved. But you are correct, most finishing products are considered hazmat and can be a headache to ship, especially through the air. But the vendors selling the stuff know the rules…you could just call them and ask.

-- Our village hasn't lost it's idiot, he was elected to congress.

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pontic

637 posts in 805 days


#14 posted 12-28-2017 03:08 PM

Arn’t you putting a finish on a finish? Where is the penetratingoil going to go?
Polyestersare flexable enough onthere own for that purpose.

-- Illigitimii non carburundum sum

View johnstoneb's profile

johnstoneb

3052 posts in 2369 days


#15 posted 12-28-2017 04:02 PM

The reason for the marine or spar varnish over the epoxy is UV protection. The fiberglass or epoxy resin has no UV protection.

-- Bruce, Boise, ID

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