Replies

1. 
   MikeHennessy | Feb 24, 2009 05:01pm | #1

   Well, start by using white oak. ;-)  (Red is not so hot outdoors.)

   Obviously, paint would be your best choice, but if you're looking for a clear finish, spar varnish would probably be your best bet. You'll have to re-do it every year or so.

   Mike Hennessy
   Pittsburgh, PA

2. 
   doorboy | Feb 24, 2009 06:04pm | #2

   Mike is right. Spar varnish. Keep it out of the elements as much as possible. Regular maintenance. And don't expect too long of a lifespan.
3. 
   HowardAcheson | Feb 24, 2009 06:28pm | #3

   What is the item you are finishing?

   Understand that red oak is a very poor wood for use in an outdoor environment.

   Howie.........
4. 
   SteveSchoene | Feb 24, 2009 06:39pm | #4

   Yes, if at all possible use white oak or a better outdoor wood than red oak, which is one of the worst.  Red oak has large pore that are quite open for long lengths.  It's much like a bundle of straws.  Red oak can absorb moisture to such a great extent that it can then rot from the inside out. 

   If you are stuck on the wood, taking extraordinary methods to keep out moisture is called for.  In particular sealing coat of low viscosity epoxy is a good idea.  Particular attention needs be given to end grain.  It should be given enough epoxy that it will accept no more. 

   Then for a top coat.  A good gloss enamel, in one of the lighter colors, is by far the best and will outlast any clear finish, dramatically so if the object gets sun to any large degree. 

   If you must have a clear finish (and the extra work involved certainly is better than alimony) use a good spar varnish over the epoxy.  This is an area where there are dramatic quality differences among products.  You want marine spar varnish of a kind that comes from boating supply stores, and is never found at the big box home improvement stores, and rarely at paint stores or hardware stores (except possibly in coastal boat crazed communities)  Expect to pay closer to $30 a quart than $20, and follow the manufacturers directions, which generally call for around 6 coats of brushed on varnish.  Thin only to improve flow out (perhaps 10%)

   Then expect to sand and add a refresher coat once a year--perhaps every other year if it gets shade or if you are located rather far north.  

   But again, the best thing to do is to use white oak and no finish.     

    

5. 
   bleubassplyr | Feb 25, 2009 07:16am | #5

   Hello,

   This is a question that is raised every couple years. I found a long thread on Knots which I posted below. I’ve done sample tests myself and have tried different finishes through the years on the hundreds of picnic tables I’ve built. By far the best have been Man O’ war spar varnish, solid red and clear, Krylon pigmented polyurethane, which I haven’t seen lately, and Behr Premium Weatherproofing Wood Sealer and Finish. The only negative with the Behr is that it is silicone based and has a slightly slippery feel for a few months and you have to apply it quickly or the brush marks will show later. When done correctly it offers good protection and looks good too.

    

   Good luck. Bleu

    

   From Knots.

   I wouldn't waste time with Thompson's.  It's paraffin (wax) based - looks like it's doing a great job when you first put it on because the water really beads up.  But what happens to wax in sunshine.......?

    

   Sikkens is the best of the barrier coats.  It is the Cetol System you want, and should be able to find it at good paint stores.  In 35 years of professional door building, it is the only finish I recommend. Oil finishes will not last (more than a few weeks) if there is any ambient UV.

   Sikkens Cetol is flexible and workable.  When it fails (as all exterior wood finishes do) it merely looks dull and physically worn, and can then re-topcoated in a day.   It does not crack or peel if applied correctly.  Also good for both sides.

    

    

   Post # 23121.1 at Knots

    

   I found this article in about '98, lost it and just found it again.  Some very interesting observations that I've never seen anywhere else: 

    

   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 "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 "spar" varnish 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 poly floor paint and the 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 oilbased 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 folk 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

   Alan & Lynette Mikkelsen, Mountain View Farm, est. 1934,  Gardens & Fine Woodworking, St. Ignatius, MT

    

   And here was one more testimonial to the procedure....

   My recollection is that Jim made this post back in July, 2002 (at least that is when I saved it on my computer).  Prior to the complete explaination he would post bits of the same information.  About a  year and a month or two before this post (spring of '01) I was talking with Jim while driving to Virginia to assist my brother-in-law with some  maintenance on their log home.  One of the tasks on the schedule was to refinish their south facing, no overhang front door...again!  It was at that time that Jim informed me of his "test".  A couple of days later the door was stripped, sanded, and "painted" with Olympic brand exterior      oil-based paint base #5.  By my count that's coming up on five years. 

                                 

    Just before making this post I called my brother-in-law to see how the door is doing.  The report is that the door looks as good as it did after we refinished it back in '01—it shows no

   signs of cracking, yellowing, or any of the other common traits of Helmsman Spar Urethane in a similar high sun exposure; the builder recomended finish of choice before Jim's advice.

                                 

   I have used a couple of other brands and find that all perform pretty much the same so long as you get the paint base used to mix the darkest colors. Testing, however, is always appropriate.  I can also sympathize with lack of help you have

   received from your local S&W dealer.  As soon as you explain to the typical paint store employee what you intend to do the reaction is generally the same—"Oh, that won't work..."  On one of my let's-have-some-fun-with-this-guy visits to a local Benjamin Moore dealer last summer I explained the concept to the salesman behind the counter.  He assured me with great certainty that I was completely wrong (I getting accostum to

   hearing that) and that what I proposed wouldn't work.  I asked him to open a can of the appropriate base and just stick a wooden stir stick into the paint.  When he withdrew the stick

   he showed me with great pride how cloudy and milky it was.  I told him to set it aside and I would return later.  When I did his response changed;  "OK, its clear; but, it still won't work—if you

   don't add the pigment the paint won't stick right" (his words).

                                 

   So, off to Lowe's with you, get the #5 base and have some fun...

                                 

                                 Steve

   Alan & Lynette Mikkelsen, Mountain View Farm, est. 1934,  Gardens & Fine Woodworking, St. Ignatius, MT

    

   And another

   Polyurethane is one of the worst finishes for exterior work, worse even than Tung oil. It will fail - as do all exterior wood finishes - and will crack and peel when it does, necessitating a scrape and sand and chemical removal and total refinish of the door.  I would try a test corner 3" square to see if the Cetol will adhere ok.  I'd do mineral spirits woipe down first, perhaps with a fine 3m pad.   

   Use Sikkens Cetol 3 coat System for exterior doors and windows.  It was developed for the very strong European door market, and designed for easy recoating.  I tell my customers to use a .39 cent foam brush and recoat on a Saturday morning, and you can lock up at sundown.

   Long story short, I'm a professional doormaker for 30 years.  Along with that, I'm a door finish debunker also. 

   http://www.acornwoodworks.com  go to the page on "Doors"  Most of thses are Sikkens finishes.

    

    

    

   There are more old drunkards than old doctors.  Ben Franklin

1. 
   SteveSchoene | Feb 25, 2009 03:41pm | #6

   The "paint base" idea comes up with some regularity.  Some people swear by it, but the only supporting evidence that I've ever seen has been some anecdotal stories about it's effectiveness.  I can't say it doesn't work well, since I haven't seen any real testing the other direction either. 

   I can say that I am quite sceptical.   Pigment in paint is the primary thing that protects the wood underneath--when light, including UV can't penetrate it can't damage the lignin binding the wood fibers together on the surface of the board.  So manufacturer's would see no need in paint base for the additives called hindered amine light stabilizers (HALs). whose function is to protect the wood under the film--it wouldn't have a benefit in the way they expect the product to be used.  HALS are included in marine spar varnishes.  Paint manufacturer's might possibly use some UV absorbers (UVAs) that are designed to protect the resins in the finish, to protect resins on the surface. 

   And, my scepticism has to do with the economics.   Marine spar varnish is usually around $30 a quart, house trim paint is sold for a bit more than $30 per gallon.  Why put in expensive UV protectants that aren't needed in paint with pigment, especially when your costs are limited by markets with lower selling prices.  Paint base may well have additives, such as mildewcides that aren't in marine spar varnish, but for items kept in the sun those are irrelevant. 

   Besides is pretty uncommon to see house trim paint in the full gloss levels of a spar varnish. 

    

1. 
   bleubassplyr | Feb 25, 2009 06:08pm | #7

   Thanks for the reply Steve. I can't argue with your answer. I have not had a chance to try it out myself. I thought it was interesting. The bottom line is that nothing works well in the long term on a horizontal surface outdoors. By long term I mean for more than 2 or 3 years, at best. The three products I mentioned last about 2-3 years with full exposure in the northeast USA.There are more old drunkards than old doctors.  Ben Franklin