Errol Wentworth
09-07-2006, 2:26 PM
I am mostly a lurker here, but came across some interesting testing results for exterior finishes. The testing situation was meant to simulate wood in an antique pickup truck bed--but would be similar to any horizontal exterior surface.
There are two different test years worth of testing. The second round included the use of sealers such as epoxy primer followed by a topcoat. All second round test samples performed better than the first round finishes.
The two best finishes after a year of weather exposure seem to be epoxy primer followed by varnish topcoat and POR-15 rust inhibiting paint followed by gloss black enamel. How they chose POR-15, a metal paint, as a wood primer is beyond me, as is their choice of Behr brand of enemal. I hypothesize that any combination of quality alkyd primer and exterior latex gloss enamal would perform at least as well.
Spar varnish over BLO was one of the worst performers, as was a product called Glisten--which looks to be a 2-part, moisture cured clear topcoat designed primarily for use over metal.
I do wish the test had included two other entries:
#1: CPES + multiple coats of a perceived higher-quality varnish (they used Helmsman), such as Epiphanes
#2: CPES + multiple coats of #4/5 tint base
I'm guessing #2 would be the best performer of all the clear finishes.
Since I am not sure whether links are allowed, if you want to read the entire results just Google, "pickup wood finish testing". The test results are in the first search result.
I'd be interested in other's interpretations of the findings.
Errol
There are two different test years worth of testing. The second round included the use of sealers such as epoxy primer followed by a topcoat. All second round test samples performed better than the first round finishes.
The two best finishes after a year of weather exposure seem to be epoxy primer followed by varnish topcoat and POR-15 rust inhibiting paint followed by gloss black enamel. How they chose POR-15, a metal paint, as a wood primer is beyond me, as is their choice of Behr brand of enemal. I hypothesize that any combination of quality alkyd primer and exterior latex gloss enamal would perform at least as well.
Spar varnish over BLO was one of the worst performers, as was a product called Glisten--which looks to be a 2-part, moisture cured clear topcoat designed primarily for use over metal.
I do wish the test had included two other entries:
#1: CPES + multiple coats of a perceived higher-quality varnish (they used Helmsman), such as Epiphanes
#2: CPES + multiple coats of #4/5 tint base
I'm guessing #2 would be the best performer of all the clear finishes.
Since I am not sure whether links are allowed, if you want to read the entire results just Google, "pickup wood finish testing". The test results are in the first search result.
I'd be interested in other's interpretations of the findings.
Errol