Sealing Black Cork

D

Dave Walker

Active member
I have some black cork Whistlers I'm working on right now. Was curious about sealing them. Does the black cork actually need sealer? IS one coat of spar enough if I plan to prime and paint, or should I put on another coat of spar?

Dave
 
Dave
I seal BSC with a minimum of 2 coats of 1/2 spar 1/2 mineral spirits. I dump a gallon of each into a 5 gal bucket and submerge the decoy until it stops bubbling, then it drip for 20-30 mins then off to dry for at least 24 hours before the next coat.

Just how I do it, not the bible, but it works for me.
 
Al McCormick, who only worked with Black Cork, was to fill the big voidswith plastic woodand then use spar varnish and cork dust. Very messy but I'm still using his decoys 45 years later
 
Watched Al work--He had some method!
Was going to suggest filling with a slurry of bsc dust and val-oil, if you can find it, or some other marine varnish. Using rubger gloves, smear the slurry into the voits and let dry, then sand. I have some oldies here from that method, and though they are now stored, the surface is still in great shape-Problem with bsc is the dust and chunk stuff.
Good luck and have fun--wear a mask!!!
Oh, it is advisable to work outdoors with that stuff, unless you are single. hehehehhe
 
I used to use black cork and sealed with spar varnish and never had any problems with them soaking up water.

I switched to the yellow cork and because of its construction (bound with glue rather than compression) I had never used a sealer of any type.

I had not made decoys for a number of years and then in 2010 I got feeling froggy and decided to hit it hard again - making two dozen divers = bluebills and redheads. When buying the cork for this project, the supplier convinced me to seal them with Val-oil, which I did.

The decoys were sealed with Val-oil and then totally coated in an oil based flat marine enamel (Lou Tisch paint) in black before adding the finished paint job. The problem: this year I noted that these decoys are becoming water logged over the course of the season. I probably just noticed it this year as I recently retired and was able to hunt a lot more this season. In fact, I just put some away last week and noted the puddle of water underneath them on the shelf.

so my question is - did I just get a bad batch of yellow cork? Has the composition of the yellow cork blocks changed over the years? Did the Val-oil somehow breakdown the binding agent of the cork and allow it to absorb moisture? I am befuddled
 
dale, how did you attach the rigging? if you puncture the compressed cork with anything they will now take on water. In the past, with Wiley cork, this was not a problem.
 
Everyone is giving good advice so far. I use the 1/2 spar and 1/2 mineral spirits but brush it on heavy. I fill major voids with cork dust and
Tite Bond III mix. As mentioned I use the Tite Bond to help seal around anything that goes through the cork and then seal with 2-3 coats
of the spar mix. Good luck, have fun, John
 
Dave, I fill the voids with a mix of fine saw dust and Titebond II or III. Then I liberaly coat the body with Thompson's Water Sealer, then use oil paint. The deeks I have done so with have lasted many years without appearing to absorb water.

John Bourbon
 
Kris
Thanks for the info - I do in fact conect the head through the body and keel with a screw eye as well as putting a deck screw through the back of the decoy into the keel (wolmanized lumber). I had purchased my cork through Wiley for a number of years but the last purchase I made was through Jelinek cork Co.

Is there a procedure for sealing up these "punctures" that you have found to be successful?
 
Does the black cork actually need sealer?

Dave
Click to expand...

Someone correct me if I'm wrong, but weren't some of the old Bean black ducks unsealed BSC? And isn't the biggest problem that they dry out and crumble (even more than not dried out?)

Dave, if you put the time into carving them, I would seal them, to protect your investment of time. Spar, Val-oil, gym floor sealer and similar coatings are the most tried and true. Some will dilute wood glue and mix in cork dust and smear it on. I did two a couple weeks ago that I used diluted latex Kilz as a sealer. You could see any spots missed by the first coat well, as the black showed through.

As far as your water infiltrating, when I run a fastner through any decoy, I like to put some tightbond 2 on the threads as they go in, so they bite and seal as it goes. Many ways to skin a cat, this has worked (so far) for me.

Chuck
 
Chuck,

How about 1/2 wrong? The old Bean's were sealed up to above the waterline with a shoe glue (at least that's the rumor - I'm not sure I can make out the glue under the paint). Above was just painted. And yes they do get fragile with age, no bottom board but a neat head mounting system. I have one (Drake Mallard) that my Aunt gave her new husband for his birthday in 1950. He was a hunter and she was from solid Cape Cod stock. Unfortunately for him he wasn't a duck hunter and it sat unused in his "man room" until I inherited it.

Scott
 
Scott, thank you, I feel much better now. Wasn't the theory that the paint really just gave them the color in the right spots, and the cork was allowed to breathe and dry out between uses...or am I hitting the crack pipe too much too early in the day?
 
I like the Val-oil sealing process as well on certain decoys, but for black cork "hunters" I prefer shooting them with spray truck bedliner. This is going against the grain of the thread, but I wanted to offer another option. Adding the effort of sawdust and glue or plastic wood adds alot more weight to the decoy and, depending on the voids, make it ride a little funny. The bedliner spray is quick, dries fast, rubberized, gives a paintable surface and is already flat black so that 2/3's of your diver paint is already done. I have been hunting mine for several years and the only thing I do with them after hunting is take them out of the slotted bags and them "breath". My favorite is Rustoleum Professional Grade bedliner spray found in the Walmart auto section in a tall red white and black can. Just my two cents.

dc
 
In the late 70"s I made all of my blocks from refrigeration grade cork. I used marine spar varnish thinned to approx.30 to 50% with mineral spirits. A couple of coats harden the cork and seal them up nicely( drying time is greatly reduced when thinned). If you are doing black ducks, thompsons water seal mixed with a dark walnut minwax stain works good too. Don't use the thompsons if you plan on painting as the active ingredient in thompsons is wax.
 
Thanks for the replies. I had alredy put on a coat of Spar Varnish, so I think the dipping idea would have had issues. I spoke a bit with Bomber and concluded that I should apply a few more coats. At this point I'm at 3 coats of spar. I hadn't filled the holes because I thought I would like the look of the "rough" black cork. I don't! I'm going to fill up the wholes with a mix of more cork dust and some spar varnish. Between that and the 3 coats already on there, primer and paint, they should be sealed up enough to last a while. I did one so far witha trestle coat like finish on the head. I'm really happy with the look it had. Now to do the rest
 
I did a dozen black cork cans and buffleheads around 25 years ago and they are still holding up well

I took all of the black cork dust and mixed it with thompsons water seal. made a paste and filled all the voids. when it dried I sanded and then primed and painted with rustoleum.

I know there are a bunch of techniques, but this is what really worked well for me
 
in the late '60's, Soule gave me a gallon of the shoe glue used to seal decoys..They coated the bird, then later just the bottom of decoy; if you find the decoys now, most repair cut spar varnish, and 3 or 4 coats generally seal the black cork. I have his birds sealed this way for 25 years, still ok.
 
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