(07-14-2019, 10:20 PM)wood2woodknot Wrote: I am looking for the original review on using untinted deep base enamel as an outdoor clear finish.
It was was written by a fellow named Steve (forget his last name) at Hardwood Lumber and More in Milford, Ohio. He closed the store several years ago, but wrote for one of the magazines.
I would like to find that original how-to article. I have lost my copy after several computer upgrades and replacements.
Can anyone give me a heads up?
The article was written by Jim Kull, who was the Wood magazine finishing forum host at the time. Steve Mickley added some of his slant on the article and published it on his website. Bear in mind that he refers to oil based paint which is getting harder to find. Mac (Kevin McReynolds) used the SW A100 (acrylic) on an outdoor cross and it seems to be working well. Here is the article posted by our own Howie some time ago:
Here are the details on using "clear paint".
OUOTE
In a recent post my friend, Steve, made reference to my tests of doggie sprinkling on exterior finishes. I figure after almost a year of testing it is time to post some interesting discoveries.
As a preface, allow me to set the stage. Almost daily there is a posting about clear, exterior finishes for doors, chairs, signs and such. Responses run the gamut from diehard marine finishes to apply a coat of primer and then paint. Each of these has a bit of a problem. Marine finishes are not always the easiest to find and it grieves me to think of a lovely oak, teak, mahogany, fir, redwood or similar nice wood door painted in mauve goop.
Bob from Fl inspired me with his continuing and accurate statements about the failings of a clear coat and the advantages of a good quality exterior paint. I decided after lots of reflection that he really was right but there was always the picture of mauve in my mind. Sooooooooo, how could one take advantage of his advice and yet capitalize on the beauty of a nice wood.
I began to reflect on the characteristics of paint. Now, comes the boredom.
There were several things I knew about paint. Exterior paints contain a mildewcide and a fungicide that a varnish does not. The best quality paints will contain a UV protectorant and trans-oxide pigments in very high percentages. Almost all paint is custom mixed by the store. The retailer maintains a large supply of base products that are used to achieve the desired color. There are generally 4 base products and the specific one for your paint is determined by your color choice. These base products are either named or numbered. They are named pastel, deep, tint and neutral. If numbered it is cleverly 1, 2, 3 and 4 with the exception of Olympic who numbers 1, 2, 3 and 5. Olympic is unaware that 4 comes before 5. Pastel and/or 1 is virtually a pure white and used for the lightest of colors. The others are slightly color altered from white and more translucent than pastel. These are used for succeedingly deeper colors. All of this comes to neutral, 4 and/or 5. These are clear and used for the darkest colors. In the can they are somewhat opaque but dry more or less clear.
Now comes the testing. I bought 4 oak exterior doors. Each door was given one coat of the same MinWax Stain. On 3 of the doors, I applied 2 coats of "base" to the 6 sides of each door (3 coats on the top and bottom edges). Each of these three doors had a different type of exterior neutral, 4 or 5 base. The fourth door was finished with a consumer poly "spar" varnish from my local friendly paint/hardware store. The bases for the 3 painted doors were an exterior semi-gloss acrylic, an exterior semi-gloss oilbased polyurethane floor paint and a semi-gloss oilbased trim and siding paint.
The doors were set up, slightly inclined, in mostly direct sunlight under a pecan tree in the backyard. My wife just loved that one. Daily, the sprinklers managed to hit the doors. The birds in the pecan tree used the doors for target practice. And, yes, the dogs did anoint the doors on a regular basis. My blonde Cocker, Zazu, was particularly enamored with the doors. Over the course of the test the doors experienced lots of Texas sunlight, rain and snow. The temperature went from below freezing to over 100. The advantage to the inclined position of the doors was the snow, ice, water from the sprinklers and the rain tended to collect in the raised panel areas. I feel these doors were subjected to far more severe environmental conditions than would be expected from normal use.
The results were interesting. The poly "spar" varnish initially looked fabulous but after about 2 weeks it began to develop small cracks. In rapid order the door began to turn black, started to mold and the smell was enough to knock a buzzard off of a manure wagon. The waterbased acrylic is milky in the can like a waterbased poly. It dried to a more or less water clear surface but was a bit cloudy. It tended to wash out the stain a bit. Over time it became cloudier and ultimately become almost white. But, it remained solid and protected the wood. The oil based bases are also a bit opaque in the can but dried to a clear finish that is almost identical to a spar varnish - they added an amber tone to the doors. Both the oil based poly floor paint and the oil based trim and siding paint remained "clear" over the entire test period.
The testing came to an end with a bit of encouragement. My wife said something clever like, "Get those damned doors out of the backyard?". She does not understand science. The floor poly had some minor checking and a thinned coat of the same base over the surface made that disappear. The door with the oilbased trim and siding paint was perfect other than it had lost a bit of the gloss.
So, I am with Bob - paint the door. My preference is the oil based products. If you are predisposed to a waterbased use an acrylic rather than latex.
One thing you will find when you go out shopping for your product is a lack of knowledge on the part of the salesperson. Not many of these fudge are aware that their neutral or 4 base will dry clear. If you want to have some fun, spring it on them. They will suggest you are full of Donkey Dust. Ask them to shake a can and put some on a stir stick. Dry it and voila, it is clear.
Jim Kull
END QUOTE
I used the clear paint on a number of exterior doors and number of years ago (maybe 8-10) and I looked at a couple of them the last time I went back to New York. They all looked virtually perfect.
Howie.....
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
