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31-01-2017, 15:01
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#1
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Registered User
Join Date: Nov 2015
Location: San Diego
Boat: Columbia 36
Posts: 15
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Urethane vs Varnish
Boy am I confused, My local paint store has completely different advice than the internet, where no two posts seem to be able to agree either.
My question: Spar Varnish vs Spar Urethane? I am doing both interior and exterior and completely removing the old finishes (or whats left anyway) on my 1969 36' Columbia. Is one better for interior wood and one better fore exterior?
The primary differences appear to be UV protection, Water protection, and flexibility unfortunately I can find sources that tout each product as better.
What say ye?
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31-01-2017, 15:23
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#2
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,544
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Re: Urethane vs Varnish
Yes, different degrees of UV resistance are out there. It's not rocket surgery though, Darker inhibitors in the mix = more UV resistance. Compare a can of plain varnish with exterior and you will see the color difference; one clear, one rather dark with black stuff in it. Spar varnish tends to be more flexible and /or gummy. Might be great for a spar that flexes, but low resistance to scuffing or chafing by lines. Personally, for anything but a spar I prefer polyurethane as far as "varnish like" finishes.
I have tried many over the years, Varathane has worked well for me many times.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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31-01-2017, 16:07
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#3
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Registered User
Join Date: Jan 2010
Location: Port Ludlow Wa
Boat: Makela,Ingrid38,Idora
Posts: 2,050
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Re: Urethane vs Varnish
Since whatever finish you apply will require maintaining, there are more complex long and short term considerations. For interior finishes Urethane can be long lasting and resist wear and tear. (Think basketball floor) For exterior finishes (which require maintaining more frequently) you must prevent wood loss due to frequent sanding as well as provide UV protection. My latest thinking is influenced by practices I have recently seen in use in the Yard in Port Townsend. Sand and clean the wood thoroughly. Apply a coat of clear epoxy resin. Allow the epoxy to cure. Then fair the epoxy covered surface. Finally apply several coats of UV resistant varnish or Cetol. Both have similar longevity. When repair is necessary, use wet sanding to remove as much of the top coats as is necessary without penetrating the epoxy layer. Do not over sand. Then apply your repair coats. The key is to do timely repairs. Keep the UV out of the Epoxy, and sanding out of the wood.
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02-02-2017, 02:11
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#4
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Registered User
Join Date: Jul 2016
Location: Anguilla
Boat: CheoyLee Offshore 33
Posts: 644
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Re: Urethane vs Varnish
Idorakeeper, what do you mean by clear epoxy? Standard West System epoxy?
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02-02-2017, 04:43
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#5
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Registered User
Join Date: Oct 2011
Posts: 3,604
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Re: Urethane vs Varnish
Quote:
Originally Posted by IdoraKeeper
My latest thinking is influenced by practices I have recently seen in use in the Yard in Port Townsend. Sand and clean the wood thoroughly. Apply a coat of clear epoxy resin. Allow the epoxy to cure. Then fair the epoxy covered surface. Finally apply several coats of UV resistant varnish or Cetol. Both have similar longevity. When repair is necessary, use wet sanding to remove as much of the top coats as is necessary without penetrating the epoxy layer. Do not over sand. Then apply your repair coats. The key is to do timely repairs. Keep the UV out of the Epoxy, and sanding out of the wood.
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What is being described is a neat little corner-cutting trick that can save a lot of time and effort required to build up a sufficient base layer (10 coats) of varnish to achieve that delicious candy coating look everyone loves.
While a neat trick and a potentially huge time saver, a recommendation to use it should not come without a warning.
Varnishes intended to outdoor contain the aforementioned UV inhibitors. These don't of last forever. Hence the requirement for the application of seasonal maintenance coats of more varnish. Meanwhile, epoxy typically has very poor UV resistance and can turn opaque in a very short amount of time with direct exposure to the sun.
Here's the caution with using epoxy as a base for varnish - if you slack off on your varnish maintenance even for a season you can expect the epoxy to turn. Once the epoxy turns you can either paint over the wood, or get out the scrapers, heat gun, and tough-guy 60 grit sandpaper because you're gonna have to take it back down to bare wood if you ever want to a have that delicious candy coating again. Have seen it happen.
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02-02-2017, 09:04
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#6
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,544
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Re: Urethane vs Varnish
Quote:
Originally Posted by Delancey
What is being described is a neat little corner-cutting trick that can save a lot of time and effort required to build up a sufficient base layer (10 coats) of varnish to achieve that delicious candy coating look everyone loves.
While a neat trick and a potentially huge time saver, a recommendation to use it should not come without a warning.
Varnishes intended to outdoor contain the aforementioned UV inhibitors. These don't of last forever. Hence the requirement for the application of seasonal maintenance coats of more varnish. Meanwhile, epoxy typically has very poor UV resistance and can turn opaque in a very short amount of time with direct exposure to the sun.
Here's the caution with using epoxy as a base for varnish - if you slack off on your varnish maintenance even for a season you can expect the epoxy to turn. Once the epoxy turns you can either paint over the wood, or get out the scrapers, heat gun, and tough-guy 60 grit sandpaper because you're gonna have to take it back down to bare wood if you ever want to a have that delicious candy coating again. Have seen it happen.
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I was about to pipe up on this, glad someone did. Using epoxy undercoat has worked for people, but this caution should be big and bold. If you let it go, stripping epoxy is a nightmare. I have seen some disgusting results from neglect, milky big patches of bubbling up epoxy. A huge job to correct compared with varnish gone bad.!
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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02-02-2017, 10:14
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#7
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Registered User
Join Date: Jul 2007
Location: Toronto, Canada
Boat: Luders 33 - hull 23
Posts: 1,787
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Re: Urethane vs Varnish
Quote:
Originally Posted by Cheechako
I was about to pipe up on this, glad someone did. Using epoxy undercoat has worked for people, but this caution should be big and bold. If you let it go, stripping epoxy is a nightmare. I have seen some disgusting results from neglect, milky big patches of bubbling up epoxy. A huge job to correct compared with varnish gone bad.!
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I agree on this... but I also think it depends on the type and thickness of the epoxy used. I have used this trick on the exterior using S1 Sealer. This is diluted epoxy and very thin - it penetrates the wood and there is not much to sand if you have to. One or two coats of this, depending whether the surface is vertical or horizontal, will help immensely on minimizing the number of coats... but still needs uv protection.
But I digress...
https://www.systemthree.com/products...g-epoxy-sealer
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02-02-2017, 10:28
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#8
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,544
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Re: Urethane vs Varnish
Quote:
Originally Posted by SVTatia
I agree on this... but I also think it depends on the type and thickness of the epoxy used. I have used this trick on the exterior using S1 Sealer. This is diluted epoxy and very thin - it penetrates the wood and there is not much to sand if you have to. One or two coats of this, depending whether the surface is vertical or horizontal, will help immensely on minimizing the number of coats... but still needs uv protection.
But I digress...
https://www.systemthree.com/products...g-epoxy-sealer
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That's a good idea. One wonders though; If you have to varnish to protect the epoxy, how is that different than just varnishing every year anyway? Just thinking out loud....
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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02-02-2017, 10:38
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#9
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Registered User
Join Date: Aug 2010
Posts: 3,119
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Re: Urethane vs Varnish
Quote:
Originally Posted by Cheechako
That's a good idea. One wonders though; If you have to varnish to protect the epoxy, how is that different than just varnishing every year anyway? Just thinking out loud....
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The epoxy 'primer' allows you to skip around 8+ coats of varnish during the initial job. I tend to agree, that once the job is done, the yearly maintenance is basically the same.
Epoxy gives you a short-cut during the initial application to bare wood, but potentially exposes you to a nightmare if you aren't diligent with yearly maintenance. Varnish takes a lot more for work for the initial application, but fixing results of neglect is significantly easier.
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02-02-2017, 11:20
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#10
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Registered User
Join Date: Jan 2013
Posts: 112
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Re: Urethane vs Varnish
The trick with the epoxy is to use a Low Viscosity mixture like West Systems 105/207. This is most common referred to as a "full finish" and most boat builders prefer this method over any other. Apply 2 coats of epoxy, then 3-5 coats of your preferred varnish. I agree with the caution and have found you need to add maintenance coats every 6 months. At least here in the NW. The finish will be a little darker but should hold up for several years.
The reason to use the epoxy other than the added benefit of the mil thickness, epoxy adheres to oily woods like teak far better then varnish. The most recommended strait varnish method is to thin out with acetone and apply several coats, reducing the thinner per coat. The epoxy does a better job without thinning and saves time.
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02-02-2017, 11:38
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#11
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Registered User
Join Date: Nov 2015
Location: San Diego
Boat: Columbia 36
Posts: 15
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Re: Urethane vs Varnish
All very interesting but doesn't answer my question. Varnish or urethane?
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02-02-2017, 11:48
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#12
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Registered User
Join Date: Sep 2015
Location: Whoo! Finally made it back to Mexico!
Boat: Cheoy Lee Offshore 38
Posts: 1,458
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Re: Urethane vs Varnish
Quote:
Originally Posted by HBWT
The trick with the epoxy is to use a Low Viscosity mixture like West Systems 105/207. This is most common referred to as a "full finish" and most boat builders prefer this method over any other. Apply 2 coats of epoxy, then 3-5 coats of your preferred varnish. I agree with the caution and have found you need to add maintenance coats every 6 months. At least here in the NW. The finish will be a little darker but should hold up for several years.
The reason to use the epoxy other than the added benefit of the mil thickness, epoxy adheres to oily woods like teak far better then varnish. The most recommended strait varnish method is to thin out with acetone and apply several coats, reducing the thinner per coat. The epoxy does a better job without thinning and saves time.
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5-7 coats total, so what are we really "saving"?
And, to echo the OP, urethane or varnish?
__________________
If toast always lands butter side down, and cats always land on their feet, what would happen if you strapped toast to a cat's back and dropped it? - Steven Wright
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02-02-2017, 12:16
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#13
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Registered User
Join Date: Jun 2012
Location: Annapolis
Boat: Hylas 49
Posts: 1,125
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Re: Urethane vs Varnish
Varnish is a tung oil based product. Poly is a more flexible synthetic. If you have a Hinckley, varnish. Otherwise poly or Cetol clear. My current favorite is Epihanes RadpidClear.
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02-02-2017, 12:32
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#14
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Moderator
Join Date: Nov 2011
Location: aboard, in Tasmania, Australia
Boat: Sayer 46' Solent rig sloop
Posts: 28,663
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Re: Urethane vs Varnish
Hi, mbath,
I don't know what is best for you, minaret or Mainesail can probably tell you.
For what we have done, is use the best spar varnish we can find for the exterior trim, and you really do need to build up the coats, and give a light sanding and re-coat within 6 mo, even then. That will do your halo strip and hand rails.
For the cabin sole, we used high gloss (without flatting agents) urethane, and also on the high wear areas, like fiddles in the galley, built in dish & cups area, and partial bulkheads you grab when you move around the boat, and the rest of the interior with a satin finish urethane. If you're careful, you can lightly sand and re-varnish the parts of the high wear areas that get worn, without doing the whole bit. It is a matter of taste, some people like the high gloss all over, for me, it's a little much....suit yourself.
Use a good brush. Not the foam brushes nor the cheapest bristle brushes. Spend lots of thinner cleaning it. You will get far better results with a good brush. Again, I'm certain minaret could make a good recommendation. You can see some of his work on the thread "Nauticat 52 Re-fit". If his answer comes back real varnish everywhere, that is what i would try next time.
Ann
On edit, I want to add that if the wood is really banged up, the high gloss will show up the nicks and grooves, until you have built up enough layers for them to be full. This is very time consuming, I'd put it in the "work of love" category. We have a friend who circumnavigated who filled the dings with clear epoxy, standing a little proud, then, when it was almost set, cut the top off with a single edge razor blade, then sand smooth to the wood, and then varnish. We have never tried this method, but it's something to think about. It's one of those things you might have to be a perfectionist to really understand.
Our present boat has matte finish on the cabin sole and high gloss elsewhere. The cabin sole tends to get beat up by dropping things on it, and when we do it, we will probably keep it matte, because all the rest is high gloss.
Ann
__________________
Who scorns the calm has forgotten the storm.
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02-02-2017, 13:36
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#15
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Registered User
Join Date: Nov 2015
Location: San Diego
Boat: Columbia 36
Posts: 15
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Re: Urethane vs Varnish
Thanks Ann. Why varnish outside instead of urethane everywhere?
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