Finishing Fiberglass exterior door

[Gary Senn]

We had a new home built in 2012 and had all woodgrain fiberglass exterior doors installed. The contractor had finished the doors using a gel stain and poly top coat. On two doors with direct sunlight exposure the finish had almost completely flaked off in one year. I need to refinish these two doors. I've bought exterior UV resistant poly and was considering mixing my stain into the poly rather than putting gel stain under it to hopefully improve the adhesion of the poly to the fiberglass. Has anyone had experience with finishing fiberglass doors exposed to direct sun?
Gary

[Steve Schoene]

Mixing the stain with the poly is a very bad idea. It makes getting an even coloration very difficult. The problem is the poly. Single part polyurethane finishes are not very good at UV resistance. You would be better off with a marine spar varnish--without poly. This is NOT available at the big box stores, or at ordinary paint stores. Brands include Iterlux Schooner, Petitt Capain's, and perhaps in the top spot, Epifanes Gloss.

Frankly you would be better off with paint. Top quallty enamel, such as from Fine Paints of Europe makes really excellent door finishes.

[John TenEyck]

Take a look at General Finishes exterior stains and 450 Topcoat: http://generalfinishes.com/professional-products/water-base-exterior-finishes The 450 Topcoat gets very good reviews from folks here who have used it.

John

[Rick Mosher]

Nothing is going to hold up in direct sun. You'll be re-doing it again. Is there any way to build a small porch roof, dormer or trellis of some kind to protect the door from the direct sun?

[Sam Murdoch]

I hope to get more info on this topic. Will be taking on the same job this fall.
All recommendations/experience welcome.

[Jason Roehl]

I've had very good success with the ZAR WB exterior polyurethane. I don't know that I've put it on a door in direct sunlight, but I did do some fiberglass doors on a 4-plex 12 years ago. I was just there a couple weeks ago, and the finish still looks decent, but could use a re-coat. I don't recall what I used for a stain, but I have used standard ol' Minwax in the past, though I find the Therma-Tru kits to be good, which come with a thicker stain that's not quite like a gel.

[Tom McMahon]

Kwickkleen out of Indiana published a news letter a while back on how to finish fiberglass doors. I no longer have it but you should be able to get it from them. As I recall it involved a particular primer.

[Rich Engelhardt]

Has anyone had experience with finishing fiberglass doors exposed to direct sun?Yes. Both fiberglass and steel.

First step is to remove anything on the door.

If the door is new - or - once you are down to a clean unfinished surface - wipe it down with Xylol and apply a coat of XIM flash bond primer. (either #400 white or clear)
Do not substitute anything else (such as Naphtha or mineral spirits) to wipe down the surface. It's critical to the adhesion of the XIM that no trace of oil or residue is on the surface and only Xylol will not leave a residue.

Allow the XIM to dry as per the instructions on the can.

The next step is a little tricky since a lot of the products I used in the past are no longer available.

You need to apply a ground coat of an oil based enamel.
I used Glidden All Purpose Gloss Enamel (similar to Rustoleum) in the color Acorn Brown.

Can a 100% acrylic be substituted?
I honestly don't know. From my experience with that product, it has good to excellent adhesion and it wears pretty well. I'd give it a try.

Be aware though that if you go with an oil base ground coat, you top coat the XIM while it's slightly tacky. XIM will even tell you that if the XIM dries too hard, you have to wipe it down with Xylol to revive some of the tack.

If you go with the 100% acrylic as a top coat, then you have to let the XIM dry until it's hard.

Once the ground coat has dried, then you apply a color fast wiping stain as a grain coat.

Once the grain coat has dried completly, then apply 4 to 7 coats of an exterior spar (or better yet marine) grade varnish that has UV blockers.
I used to use just a plain old phoenelic spar varnish.

The only two tricky parts to it are - putting the (correct) primer onto a perfectly clean and prepared surface and using a colorfast wiping stain.

As far as the graining step goes, you can experiment with all sorts of different combinations of ground coat and grain coat.
A light tan ground coat and a "golden oak" grain coat can simulate oak. A darker brown base coat and a "walnut" stain can simulate walnut.
There should be a lot of tutorials and/or You Tube videos about how to grain.