Latex paint over spar varnish?

I have an exterior door that was varnished. I want to paint it the same color of the trim on the house with latex paint. What preparation do I need to do? TIA Max

Reply to
Max
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Sand it. Dave

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Reply to
Teamcasa

"Teamcasa" wrote

That's it? Thanks. Consider it done.

Max

Reply to
Max

Max:

I would probably do more than just sand. But then I have to put out a warrantable product so my take may be different than some. Solvent based finishes often do not lend themselves willingly to adhesion of other products, especially after they have aged, and worse still if they are damaged.

Before anyone craps a banana, this of course excludes all build finishes. But in this case, we are talking varnish.

As a sidebar, if the clear finish (no matter what it is) is dried out, cracked, discolored, crumbly, or the wood underneath is discolored, the finish is gone. All you are seeing when the surface is in this condition is the last 5% of the finish, just the part that hasn't fallen off. In this case, simply sanding off the crumbles won't work, you must strip and sand to get to a good bondable substrate.

Anyway, it begs the question Max, how do you know it's varnish? When we refinish a door, we have found that most homeowners and many contractors use polyurethane for original finish, and then for refinish. If it is a homeowner job you are looking at, you can almost bet it was poly. Varnish and poly are two different animals, and if it is poly, you should count on stripping the door before painting.

Me, I would strip anyway to be absolutely sure, especially since you are probably talking about one side only. The oils, resins, and hardners in the varnish (if that is what it is) have no doubt penetrated the wood over the years, so there are things in the wood that could kill your adhesion. And since you are going back over it with paint, you wouldn't have to have the surface "perfect" before painting, especially if you go back with oil based paint.

If you want to go latex, strip, coat the stripped side with KILZ 2 to seal the resins in the wood and to assist in bonding, sand lightly when dry, vacuum up the particles left from sanding, then put a couple of coats of paint on it.

If you don't want to strip, clean the door up, sand the snot out of it, vacuum up the particles, wipe down with thinner, seal it with the original KILZ (for bonding purposes) and have your paint store match a quart of oil based urethane to your latex color. It may be cheaper (stripper for latex = $20; quart of custom mix oil base = $12) and easier to avoid stripping and just to bite the bullet and buy a quart of oil based paint. A couple of coats and you are finished.

Hope this helps.

Robert

Reply to
nailshooter41

Or: Wipe it down with solvent to clean the foreign oils off and dewax it (some people do wax the door) Then wipe it down with denatured alcohol to get the last bit of solvent off. Solvent leaves a residue. Then sand it. Then wipe it down with a damp sponge to get the dust off. More denatured alcohol to get the water and water borne crap and the dust you missed off. Use a decent oil base primer to bite the sanded varnish and give the latex a good bite. Then two coats of latex. After a year or two, the latex may still be stuck to the door or maybe not.

The door, unlike a wall, will get substantial abuse from kicking, touching, licking (dogs, kids), staining, etc. Why not go with an oil base paint the same color as the trim?

Pete

Reply to
cselby

You've said a mouthful. Being the guy I am, I had to learn the hard way. I too wanted to use latex over a "varnished" surface at my house. In my case, it was the risers on some interior steps. In no way shape or form was that paint (Sherwin Williams superpaint) going to adhere.

I ended up using a heat gun and stripping it all off. It was a time consuming PITA, but the results after sanding the scraped surface is perfect. A beautifully smooth surface with excellent adhesion.

I say strip the old surface in whatever manner you want then sand 'er smooth. Then apply the paint.

Reply to
George Max

Thanks for the info, Robert. I know it's varnish because I applied it. The house has 5 exterior doors. I sprayed them about 10 years ago with McCloskey's Marine varnish and they really look good. The one I want to paint the color of the house trim is at the back of the (attached) garage. I'm not adverse to stripping the door but I didn't want to if I didn't have to. And I don't mind spending whatever I have to for a good finish. The paint I used on the trim (Glidden Endurance) seems to be holding up very well. I'm wondering about the durability of an oil based paint. What's your verdict?

Max

Reply to
Max

"George Max" wrote

Thanks, George. I had an idea that stripping might be required but I didn't want to if I didn't have to. On the other hand, I want a good finish and I'm willing to do whatever I have to do to get it. I have a good heat gun and I can get stripper. Which do you think would be better? I'm not fond of stripper because of the fumes and the mess but if it's what I have to do, I'm game.

Max

Reply to
Max

Max wrote:

Reply to
nailshooter41

Well, the steps I did were to scrape the finish off with a heat gun, then wipe the surface with a rag dipped in a liquid stripper (Kleen Kutter) then sand. The surface looked almost as good as new.

I then primed with latex primer and painted with the latex top coat.

If your stripping a door, I imagine there will be nooks and crannies not easily sanded or scraped, therefore I'd use stripper.

With regards to the actual finish you'll apply after doing all that, others have also rendered good advise. Read it all and decide what you need given your particular needs and circumstances.

Reply to
George Max

Thanks again, Robert.

I have a couple of things working in my favor. I'm retired. Plenty of time to do it right. I have a piece of 3/4" OSB that I cut to fit the opening for the door so I can have the door off for as long as I need to. I have a DeVilbiss high pressure sprayer, a couple touch up guns and a Fuji Q4. I'm going to get the door stripped down and then decide what final finish I want. I'm leaning toward the urethane just because I want to see how it looks and how it lasts. I'll keep you *posted*.

Max

Reply to
Max

Thank you, George. I appreciate the advice. I think I'll start with the heat gun and see how it goes. If I need stripper, I'll move on to that.

Max

Reply to
Max

Wow. I have 2 heat guns and I had never tried using one to remove paint (or varnish). It's taking it off very nicely. See the pics at the bottom. (titled "door")

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Gentlemen, Thank you for your help.

Max

Reply to
Max

"Max"

Hey Max, Nice screen door - We have something in common.

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glad the heat gun is working for you, however, as I said before, sand it and paint it - but that's ship has sailed! Dave

Reply to
Teamcasa

Hey, that Miller is almost like mine. By the way, there is a Ford dealership here that is named Casa Ford and their signs say, "Team Casa".

Max

Reply to
Max

"George Max" wrote: >

That's why Fein makes a detail sander.

Lew

Reply to
Lew Hodgett

Max, I see that you have a Q4. If you are still following this thread, would you mind answering a few questions about it? If you do, I'll post my email and we can do it offline if you prefer. Or here, it doesn't matter.

Robert

Reply to
nailshooter41

Its my ministry

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Reply to
TeamCasa

Interesting scaffolding, what brand/model is it? Or is it homemade? Joe

Reply to
Joe Gorman

"TeamCasa"

Great work, Dave. We wish you continuing success.

Max

Reply to
Max

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