Paint Exterior Door that is in Sun

Question

I have a Mahogany door that costs me about $700/year to keep it stained and covered in urethane. It is in direct sun and just takes a beating.

I don't want to put a storm door on it because the storm door will just raise the temperature even further.

I am tired of the time it takes; I am tired of the money it takes. I just going to have it painted.

I had one painter casually recommend equipment paint but did not give me a specific brand (he was not going to do the work).

I had another painter recommend Sherwin-Williams Duration Gloss.

Should I investigate further on getting the door painted with equipment paint?

Answer 1

I take it for $700 you are paying people to do this work. And I gather these are garden variety handymen using random products bought at the local builder supply; when people say "polyurethane" without any qualifiers, they usually mean the Home Depot stuff.

Have you talked to marine/boat painting places? There are a variety of products intended for marine brightwork which will perform much, much better. Because, obviously, they operate in VERY challenging environments.

Oh, and to head off a common misnomer about marine products, "Spar" varnish is not the stuff. Spar varnish is lousy varnish which has all its best properties compromised away so it can flex without cracking, as it needs to do on spars. If you're not regularly bowing that door 2" every time you open it, you don't need or want spar varnish.

Now if you're really, really hellbound and determined to paint that door, the products your painter was talking about are alkyd enamels. They're not water-based, so they are stinky. They are also illegal to apply to buildings in some jurisdictions, but there's a weird loophole that lets you buy them in quart cans. My Sherwin Williams dealer cheerfully sells me alkyds by the gallon, but is always "out of gallon cans" and sends me out the door with four quarts. (I actually am painting industrial machinery; I think they just don't believe me).

While you're at the boat place, you can also ask them about marine LPU. This is a 2-component linear aliphatic polyurethane like you haven't met before; same basic stuff as Imron and what they paint airplanes with. That stuff, I do use on architectural surfaces. I have doors I painted 8 years ago. You can't tell I didn't paint it last week.

Answer 2

This is a beautiful door and it would be a huge shame to paint it. (And if/when the paint does start to crack, it will look far worse than it does now!) It should absolutely be able to withstand direct sunlight for years with proper finish.

Contrary to what I think Harper's answer is saying, I may disagree in part. I have had very good results with "spar urethane" products you can buy in stores. The ones I've used are not low-quality, non-PU/non-polymerizing varnishes, but formulations with less ridigity/brittleness and much higher resistance to UV (which you'll immediately notice by the ambering effect - the transmission cutoff starts way below UV range, down in visible blue). Anything sold as "extra clear" or "non ambering" is junk - it means it's not doing its job to protect against UV. And the softness is not just about spars (marine) needing to bend. Wood under repeated variations in temperature and humidity will expand and contract, and if the coating is not soft, it will eventually crack as that happens, and once it cracks, it offers little or no protection.

The above is based on my experience - all the trim and doors in my home are covered with a "spar urethane" product, and survived a fire (and the associated heating/drying) that took out the entire basement with no damage to the wood (or even the finish) on main floor except some charring in a couple small places subjected to direct flame for hours.

If this were my door, I'd sand it thoroughly to remove whatever remnants of unknown and unsuitable coating are left, apply oil-based stain (or clear/natural "stain" if no coloring is desired, to restore the dried-out wood), let it dry thoroughly, and apply 3 or more coats of brush-on, oil-based "spar urethane" coating, letting it dry and sanding lightly between each coat.

Answer 3

I had the door painted with this paint:

The final door looked like this 2019-12-15:

I will add pictures over the years so we can see how it wears.

Answer 4

I'm in the same dilemma, $2.5k wood front door, natural finish. Stunning when its new. but its always the clear coat cracking after about two years in direct sun.

I have already sanded and re stained and covered twice in five years, ultimately yielding the same results, a cracked and ugly front door.

I went into beast mode yesterday and stripped with p80 on orbital sander down to raw wood again. This time trying "seal one" marine coat. If that doesn't work, its probably time for a paint job.