First Wood Fin

General Discussion
1

So this is my first post, as well as my first attempt to make and glass on a fin. I work with wood for a living, so foiling the fin was not the issue. I used a piece of teak wood for the fin, as my work uses it so it was free. None of the posts I read said anything about how teak lasts over time. I was wondering if anyone had worked with teak before, and if they had delam or bubble isuues over time. I dont want to glass the fin onto the board if I know there will be isuues with it later. I probably should’ve asked beforte, but I just went for it. I laminted the fin today and it seemed like there were no issues. Didint really try for the “halo” but it ended up working out! Tell me what you think or what I could’ve done better. I’m welcome to any input, thanks!

-Lukas

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2

Never worked with Teak before.  

Wood and Poly resin work well tegether as long as the wood doesn’t have a high amount of oil (tanin sp?).  I know that teak is pretty rot resistant and might have a good amount of tanin but you know more about that than I do. 

Anyways, delamination can be seen right away.  All you have to do is try and pull the glass off the fin.  If it pulls off easy…then it most likely will delam later.  If it doesn’t pull off then I would consider it good to go. 

Bubbles are gonna come from doing a bad job of glassing.  Wet out the glass on a piece of wax paper and then place it on the wood fin.  No more bubbles.

If you are having delam issues…post up.  There are ways to get a better bond between wood and glass.

Be well,

Dave

3

Teak is a wood that does not seem to form a strong bond with poly resin.      Probably related to tannins in the wood.        I do not have hands on experience with it.       I was advised, over fifty years ago, that Teak was ‘‘too oily’’ to fiberglass it.         Much easier to shy away from it, than try to find a way to use it.      There are some products available today, that will likely overcome the bonding issues, that were not easily available a half century ago.       Soldier on.

4

Rarethat I’ve seen Teak with that much color change.

 

In my experience, Epoxy bonds stronger to wood than poly.

 

I’ve not had issues bonding to teak or other oily hardwoods like Pau Ferro, bloodwood or bubinga using epoxy.

The oils and dust of Pau Ferro is kind of crazy.  I have broken out in rash from the dust, and oil based polyurethanes refused to cure fully laid atop it, water based polyurethanes no issues, epoxy no issues.  Did not try poly resin on it, but with teh Minwax oil based polyurethane refusing to haren atop it I would not try poly resin either.

I do use acetone or DeNaturedAlcohol to pull up the surface oils, perhaps twice, last one being right before laying down epoxy on oil woods.

 

drip a drop of water on the wood, does it bead?  If so wipe again with solvent.

 

I like to use a resin wetted  gloved finger to push epoxy deep into the pores of the wood, then lay down cloth layers, then wet the layers with more resin, letting it wick and saturate, then using as little pressure on the squeegee as possible or even a bristle brush instead.

 

Clarity with many layers of cloth, is still an issue, especially older cloth exposed to high humidity levels, and I like the thinner ‘penetrating’ epoxies for such a task, my favorite being System 3 clear coat epoxy.  But it is SLOW to thicken and cure and is expensive, and stinkier than other epoxies.

 

I would like to vaccuum bag wood fins I make in the future, but of the dozens I have built, rare that i usaed the same method on 2.  still searching for a less intensive method yielding an acceptable usable strong result with proper wood clarity.

5

Hi - 

Looks good.  When I make wooden fins, I lay up 10 or 15 layers of fiberglass and sandwich it with the wood.  After foiling, I get a nice bead or spine to which the cap layers will stick.  It also gives the fin some protection in the event of impact.

Building up a glass bead will work with a solid piece of wood but watch for any bubbles between the glass layers right around the edge of the wood.  Hold it up to a brightlight and check.  If you find any, try to open a hole to the bubbles and fill them with resin.  

I did not see how many layers of fiberglass you used - even with a glass-on type fin you should add enough to keep it stiff.  Any flexing will increase the likelihood of delamination.

If it does delaminate, try scrubbing the wood with an acetone soaked rag and immediately hit the wood with some thinned out catalyzed resin.  The deeper you can get the resin to penetrate, the less likely it is you will have delam issues later.  

That said, I’ve seen a lot of wood/glass sandwiched fins eventually split apart.  They do require frequent maintenance - every chip and ding requires immediate attention or water will wick it’s way to the wood and you’ll have problems.

6

thanks for the input guys. I had put a coat of lam resin on the fin before laminating it. It wasn’t showing signs of delam a day later so I went ahead and glasses it on. I’m surprised how well it went for my first time. 

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I would reccomend using more cloth out onto board.

Staggered layers.

By the time you feather out that lamination, there will not be much there to hold fin on.

6oz. two to three layers.

I glassed on fins for a living for 5 years.

Still do them today.

8

foiling fins is a very difficult skill, it could take years and years to create a proper foil, and even then, desire is not enough.

Listen to Barry Snyder about laminating 2-3 more layers before you hotcoat it, another 5-6" out… it wouldnt take more than patch of seaweed to pop that thing off.

nice piece of wood, hope you sealed the heck out of it.

9

Ok I’ll go further out next time, thanks for the tip. I lammed two layers of 6oz on each side before mounting the fin. Then I used two more layers of 6oz staggered up the fin.