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Forum topic by woodnteeth posted 04-02-2013 12:39 AM 750 views 0 times favorited 10 replies Add to Favorites Watch
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woodnteeth

25 posts in 658 days


04-02-2013 12:39 AM

Topic tags/keywords: question finishing

I am working out my preferred finish technique with the landing nets I build and have gotten some great ideas from this forum. On my most recent net I decided to use Formby’s tung oil finish product. I really like the way it handles and looks because I like being able to rub it on with a rag and not leave brush marks. I don’t mind taking the time to do a LOT of coats. I would like to rub on all my coats so as to avoid brush marks, but I also want some UV protection and Formby’s does not offer that. So, I decided to add about a 1/2 a teaspoon of spar urethane to about a quarter cup of Formby’s tung oil finish to do some additional coats. Has anyone tried this? If so, did it work and did you notice some solids form at the bottom of your mixture? Why is that? Thanks in advance.

-- Alan


10 replies so far

View hObOmOnk's profile

hObOmOnk

1381 posts in 2875 days


#1 posted 04-02-2013 12:55 PM

Why do you think you need UV protection?

Blessings.

-- 温故知新

View Fred Hargis's profile

Fred Hargis

2037 posts in 1241 days


#2 posted 04-02-2013 01:22 PM

Urethane finishes (any, spar or not) don’t do well outdoors because of the urethane resins. Even if they ddi, that small an amount wouldn’t help much anyway, I suspect. That aside, I’m not sure why you would see solids fall out if you did mix the two (Formby’s and the spar). The Formby’s is just an alkyd/tung oil varnish diluted with MS, I would have thought the additional varnish (the spar) would have mixed in, but I’ll admit I’ve never had a reason to try it. Anyway, if you want UV protection, I think you’ll need to top coat with such a finish. You could use something like Epifanes, or you could use an oil based paint that hasn’t been tinted. The second one is a lot cheaper, would probably have to be brushed, and likely provide an appearance much like the Formby’s but the coats would be much thicker. If you’re interested in that approach the details are explained here.

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

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woodnteeth

25 posts in 658 days


#3 posted 04-02-2013 02:21 PM

Why do I think I need UV protection? Good question. I guess I have just assumed I do because of discussions I’ve had about finishing landing nets. These are drift boat landing nets and sit in the sun more than the water. I would assume I need it for two reasons.
1. to prevent changes in the colors of the wood
2. to prevent breakdown of any varnish in the finish mixture (cracking, flaking, etc.)
Maybe my assumptions are all wrong.

Regarding Spar Urethanes not doing well outside: So is it just a marketing thing that they are promoted for outdoor protection for doors, railings, etc? And why would they be used on boats, ships masts etc. if they are not good for the outdoors…or am I thinking of spar varnishes??? Don’t really know the difference. I thought varnishes were urethanes mixed with oils.

-- Alan

View Cosmicsniper's profile

Cosmicsniper

2199 posts in 1906 days


#4 posted 04-02-2013 03:04 PM

Spar varnishes are more flexibile (elastic) han a typical varnish because they typically have a phenolic resin component (at least in part). This allows it to expand and contract to moisture better, much like a latex paint would. Whereas “spar” is derived from marine usage (being a marine term), there is no guarantee that it contains UV inhibitors, so your mileage may vary with certain products.

An example of a spar varnish application recently…

A friend of mine who is about to put his house on the market needed some end caps to put at the ends of some stair treads. He brought over some “white board” from a big box store and I used it to cut out 13 caps each 3” x 11”. I finished them to match the banisters, which I did as well, and then applied water-borne poly. Within the week, each cap was cracked all over like a spider web.

Duh! I should have known that the wood would be too moist. I had to sand them back and refinish them, only this time I topped them with a spar varnish. No problems now. Even if most of the moisture disappeared during that first week, the spar helps to guarantee the results…and when you are in a time constraint, sometimes you have to do what you have to do.

-- jay, www.allaboutastro.com

View Fred Hargis's profile

Fred Hargis

2037 posts in 1241 days


#5 posted 04-02-2013 04:27 PM

Varnishes are resins cooked with a drying oil to form “varnish”. The resins can be polyurethane (or urethane), alkyd, or phenolic. The drying oils can be a long list, but mostly linseed oil, tung oil, or soya oil. Spar varnishes are usually “long oil” for the flexibility mentioned, but long oil means a higher oil content in the cooked mixture. Anything that’s to have high UV exposure needs to not be coated in a urethane resin, since they suffer (break down) in a UV rich environment. So, you can use the box store spar outside, but it will have to be renewed very often; likely annually. Go with a higher quality marine varnish (Epifanes is a tung oil/alkyd resin formula) or the untinted paint, and you will have a finish that lasts much longer. It will still have to be renewed, but it’s probably more on the order of 6-7 years. That said, I do not know if Epifanes has UV resisters in it, but the outdoor oil based paint does (and it’s a LOT cheaper).

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

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woodnteeth

25 posts in 658 days


#6 posted 04-02-2013 04:56 PM

Wow. Thanks for all the info and feedback.

-- Alan

View hObOmOnk's profile

hObOmOnk

1381 posts in 2875 days


#7 posted 04-02-2013 06:54 PM

Suggestion: Use real Spar Varnish, not so-called “Spar Urethane.”

“Spar Urethane” products tend to delaminate and peel, especially in moist environments.

I recommend using Ace Hardware (Ace Great Finishes) Spar Varnish. It is a true tung oil/phenolic resin spar varnish with UV inhibitors. It’s available is cans smaller than one gallon and is priced much less than imported Spar Varnishes.

You can buy it through Ace Hardware stores and/or special order it with drop shipping to most of their stores.

Blessings.

-- 温故知新

View woodnteeth's profile

woodnteeth

25 posts in 658 days


#8 posted 04-08-2013 07:35 PM

What about something like Thompson’s Water Seal for decks?

-- Alan

View Lee Barker's profile

Lee Barker

2169 posts in 1598 days


#9 posted 04-08-2013 10:30 PM

Regarding application, Alan, a suggestion: A high quality varnish brush will not leave brush marks. You could likely halve the number of coats of material if you were to go that direction.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View bondogaposis's profile

bondogaposis

2749 posts in 1099 days


#10 posted 04-09-2013 12:18 AM

You can also dilute varnish 50/50 w/ mineral spirits and you have a wiping varnish that you can apply w/ a rag. Epifanes varnish is big in the boat industry and would probably make a great finish for landing nets.

-- Bondo Gaposis

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