Putting paint over varnish - outside

[Retiredguy]

About three years ago I visited this forum asking for advice/counsel for a project that I was working on.  The project was making a set of church doors for an old church that was being restored.  The advice/counsel that I got was insightful and exactly right.  As a result, the project went well, the doors turned out great, and were installed.

The problem is that the people overseeing the restoration wanted the doors to be stained and varnished (three coats marine grade spar varnish).  Th doors face South and there is no shade or protection of any kind from the sun.  As a result, after two plus years the varnish is in bad shape and needs to be fixed.  My recommendation is (and was) that the doors be painter with a really good house paint.

The question is what preparation would be required to get the best longevity for the paint.  Would scuff sanding followed by a good primer, then a quality house paint be sufficient, or do they need to be stripped and sanded back to bare wood before application of primer and paint?

[fredhargis]

It will depend on the condition of the existing finish. If it's peeling and flaking, you will have to scrape that off; that will show through the top coat unless it's smoothed out somehow...like a complete stripping or possibly filling in the flaked arreas. If it just looks awful but is fairly sound, then I would scuff it, apply a good oil based primer and paint with a good exterior paint of your choosing.

[Kansas City Fireslayer]

If you want the best possible finished product, strip the doors first and then sand to 120/150. Prime then paint. This is what I’d do if I had the time and desire. I’d also lean this route is the spar varnish is thick and it’s chipping away badly or truly failing.

If it’s not failing or super thick, I’d consider sanding to smoothness and leveling the spar varnish, then prime and paint.

I would like to see some pictures.

[Restorer]

Spar varnish was the wrong product, though everyone seems to want to use it outdoors. If you wanted natural look an oil based deep tint paint with no tint added would of done you a.great.job. I use Sherwin Williams all surface for all outdoor projects and have no callbacks. Now imo you really need to sand back, as was already mentioned, to get the spar varnish off. Even priming and painting is only as.good as the remaining adhestion of spar. So the good folks have created more work to get a good job.

[Willyou]

Spar varnish was the wrong product, though everyone seems to want to use it outdoors. If you wanted natural look an oil based deep tint paint with no tint added would of done you a.great.job. I use Sherwin Williams all surface for all outdoor projects and have no callbacks.  Now imo you really need to sand back, as was already mentioned, to get the spar varnish off.  Even priming and painting is only as.good as the remaining adhestion of spar.  So the good folks have created more work to get a good job.

A couple of years ago I tested this process. I applied 3 coats of SW All Surface on all sides of a small pine plank. I placed it on the top of my fence tilted so that one face got direct sun, wind, and rain. In about 9 months, the clear untinted product was all flaking off. IMO, don't do this unless your test it for yourself and make sure it works in your climate. Apparently this product does not have any or insufficient UV protectors in the untinted product. A different product might work, but this one didn't for me.

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[jteneyck]

A couple of years ago I tested this process. I applied 3 coats of SW All Surface on all sides of a small pine plank. I placed it on the top of my fence tilted so that one face got direct sun, wind, and rain. In about 9 months, the clear untinted product was all flaking off. IMO, don't do this unless your test it for yourself and make sure it works in your climate. Apparently this product does not have any or insufficient UV protectors in the untinted product. A different product might work, but this one didn't for me.

Are you positive you used the Deep Tint Base #3, I think it is, but it could be #4?  It's the only one with the UV package.  None of the other bases will work.  

Back to the OP's project, facing directly South, or West, with no weather protection, is really tough on a wood door.  No varnish will last long without constant maintenance, as you've found out.  

Paint will give the longest protection, especially lighter colors, but it's not without its own set of issues.  If the panels get painted tight to the frames they often will crack.  If they aren't tight in the frames water gets in and starts to peal the paint where the frame meets the panels.  Thoughtful application and routine maintenance are still needed.  

If you are willing to take it back to raw wood you have options other than paint.  I have used PPG Cetol Door and Window on a couple of exterior doors now.  The first one is now 5 years old and faces directly West with no protection whatsoever.  



I built it for a friend so I get to see it regularly.  The benefit of Cetol Door and Window is that it's breathable, so it never cracks or flakes.  It slowly self-chalks, and even casual observation will tell you when it needs to be refreshed with another coat or two of product.  I originally finished the door with 2 coats of mahogany and 1 coat of clear satin.  It looked great for 2 years, good after 3, and told us on year 4 that it was time for an update, which required nothing more than cleaning with soap and water, a light scuff sanding with 220 grit, and two new coats of finish.  It looks as good as new.  It's not maintenance free, but it's the most hassle free product I've used.  

John

[Willyou]

Are you positive you used the Deep Tint Base #3, I think it is, but it could be #4?  It's the only one with the UV package.  None of the other bases will work.  


John

Yup. Sure did.

i will add that I finished an outdoor plant stand with the same product near the same time. However, it has been under cover and gets no direct sun. It has held up well.

[fredhargis]

I'm also a fan of oil based untinted paint for outdoor use, but when I tried the SW all surface I got the same results as Willyou. If fact, the wood I used (white oak) looked almost exactly like his picture. Finding a good oil based paint around here (Ohio) anymore is pretty much impossible with al the environmental stuff going on.