BillinDetroit wrote: > I am making some lawn furniture to be painted with enamel colors and > have been advised to use spar varnish as a clear coat over the enamels.
Sounds like a waste of varnish to me.
The enamel seals and protects the wood and contains built in UV inhibitors, so what else do you want/need?
I have to say, I wouldn't have a remote clue why you would put spar varnish over a high quality exterior enamel. Nothing about that makes sense to me.
Paint will last longer and provide better UV resistance (with the paint being impervious to UV penetration) than any clear coat. As long as you keep the paint surface in good shape, the furniture should last as long as you want it to. Good quality gloss enamel is a great choice if you are painting anything exterior. I would also use one of the oil based varieties as the ones they are making these days are easy to apply and wear like hell.
Just think of some of these grand old houses (80 - 100 yrs old) that had the old oil based enamels on them. When I work on a house that has been properly maintained, it is not unusual for me to pull trim off that has several coats of paint on it and the wood underneath in perfect condition.
I would also worry about the spar bonding on the enamel and staying put. Two dissimilar products and formulations, and two different uses for the product. The intent of the spar varnish is to stay soft so it can have some movement with wood when weather expands and contracts wood, give good UV resistance, and of course keep the water out.
Enamels have some elasticity, but nothing on the order of spar varnish.
I am sure somebody somewhere is doing this and swears by it, learned it from their grandfather, listened to their neighbor "the pro", etc., but I wouldn't do it.
I personally believe that they thing I would do is take the time, money and effort that I would put in applying coat of spar varnish into putting another coat of paint on the furniture..
Just use a decent brand of exterior gloss enamel. Both the "exterior" part and the "gloss" part are important in this application. "Exterior" means that it has the UV inhibitors, "gloss" so it won't be intended to chalk (flats are usually intended to chalk a bit and thus be self-cleaning to some extent--good on a house, not good on something you sit on).
If you want overkill then go to an automotive paint store and get an automotive paint, and to overkill _that_ you could then use an automotive clearcoat. You may need to consult the manufacturer for the proper primer for wood--I suspect that the fiberglass primer would do fine but it's better to check.
If you want super-overkill then go for a 2K polyurethane--Imron or Awlgrip or the like, but note that spraying that stuff you really should have an air-supplied respirator--you _may_ get away with it if you're only going to do it a few times, but eventually it will catch up with you (google "respiratory sensitizer" for the reasons).
I ran into that suggestion (spar varnish over enamel) in the plans for "Jakes Chair" by Tom Gauldin.
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good instructions, overall. Even without all the back slats on yet, the thing is solid like a tank. My next batch will have two small design tweaks and a couple engineering changes which I will make available, along with fresher photos, online, in the spirit of the original plans, under one of the GPL licenses. NB; edits and new material can be placed under the new license because they are original to me; the original material remains under its original license until Mr. Gaudlin should chose to revise it.)
Adding a coat of dingy yellow over the bright primary colors I have in mind just didn't sound right.
Thanks for confirming my earlier hunch.
I am putting the back slats on the first one in a few minutes and then oil-based primer this afternoon. I had planned to use a water-based enamel for top coat, but if an oil base is going to get me more wear / colorfastness, then that's where I'm headed.
Oh, BTW, if you start with paint as a finish, the back slats make for a inviting canvass for customization. Starting from this basic plan, I think I can see some art fair items here.
I my experience, (excluding epoxies, industrial polymers, specialty marine grades, etc.) nothing works off the shelf as well as some of today's oil based enamels. At about $30 a gallon, they are a steal.
I paint metal and wood doors with the Coronado "Corotile" alkyd enamel that I thin about 10% with VPM (high grade naptha) and in two weeks you have a tough time scratching or leaving any mark with a fingernail. It is washable, abrasion resistant and haven't had any problmes at all with it in the 5 or so years I have been using it.
I figure if it works well on wood and metal front doors (think rain, sun, handprints, scratches, etc.) it is good for just about anything.
That being said, Sherwyn Williams and Benjamin Moore also make a great exterior enamels.
the middle of the page it has a number to call to find a dealer near you. Coronado makes a lot of industrial products that are tuned to outside wear. I think they got started in that (this is just a guess) as they are in Florida. The local rep told me that they felt like they had paints and coatings that could stand 100 degree summers, hurricanes, and all manner of other tough climate conditions since they had developled them for their area.
We don't have a Coronado "store" here like Benjamin Moore, etc. However, many of the upper end stores (including my local Ben Moore) carries Coronado. So do a couple of independents, so don't just hit the phone book for "Coronado Paint Stores".
You will like this stuff when you find it. It is worth the effort.
No problem on the website. I don't have a clue as to why Google didn't find it.
If you get some and want some help/tips on application and mixing, let me know. It is urethane based, so even a low powered gun should shoot this stuff fine as it is so viscuous.
My Benj. Moore store didn't have this by that name ... so, rather than drift too far away from the alkyd, I got the B. Moore "Impervo".
I didn't notice that the Coronado Poly also mentioned alkyd.
That's looking like a mis-step on my part. What the B. Moore store had by Coronado was their "Rust Scat" ... and it does have a polyurethane alkyd. Oops. While I trust B. Moore paints to be very, very good, there was a $14.00 price difference (Rust Scat was $28, Impervo was $42).
Okay ... I'll know better next time. And there WILL be a next time.
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