Working with Teak

For the woodworkers in here: I want to make some kiteboard-like fins for my kid’s surfboard. I have nice scraps of teak from a local boatbuilder. Are there any special considerations using this wood for fins? How does it cut, sand, accept glass, resin, etc.?? Thanks, Rob Olliges

Rob,teak is very oily and it can be hard to get a bond with resin.You could try scrubbing it down real good with acetone and priming it with vinyl sealer or perhaps shellac before glassing.Doc or some of the other guys may have something better though.Teak can also irritate your skin and sinuses.

Rob, Teak is a beautiful wood with qualities that make it good for a variety of uses. It’s oily which makes it appropriate for exterior furniture and boat brightwork. However, the oil makes glueing with epoxy a must. It’s not too hard and machines nicely, BUT it has minerals in it that dull even carbide tools quickly. Be prepared to watch your router bits and planer blades go bad faster than you want. I don’t know about resin compatability, since my experience has been in the woodworking area only: finishing with spar varnishes. Doug

dont bond? maybe make em fin boxers or like the old yater polypro fins just stuff em in a routed hole with a glass and resin mass ohhhhh baby then you could leav em raw… ambrose…love that old technique…heck i like to write technique

Hey Rob, Teak is one of the most desirable of all woods for marine use. It is dense, very oily and almost impervious to rot. Many Chinese sampans are made of solid teak and last for an amazingly long time with little maintained. The sandings from it can be somewhat toxic so be sure to wear protection when you’re working with it. It takes an in-wood penetrating oil finish beautifully and is commonly used for the furniture in boat building. It’s also a top choice for deck planking. However getting resin to stick to it can be problematic. You will probably have to treat it with Oxalic acid a couple of times to get rid of the oil in wood surface so you can use epoxy fiberglass over the surface of the foil to give a good durable finish. I’m not sure what kind of tabs the fins will have or if they’ll glass-ons. Paul Jensen probably has some experience with it and hopefully he’ll chime in with some suggestions. Mahalo, Rich

I’ll go with what everybody’s said, as they beat me to it… Working teak is best done with carbide tools and carbide abrasives - silicon carbide black sandpaper for the finishing touches. As mentioned, there’s a fine silica or something in there that eats power tool cutting edges. Epoxy is definite, as is cleaning with lots of acetone or oxalic acid, though the latter tends to bleach it a lot. That’s what we use it for, mainly, getting rust stains and such out of wood. I’d go with acetone if you want the nice teak look. Do this as a last step after working it, as teak is so dense that you’re just gonna get the oils out of the surface anyhow, it won’t penetrate much. What I advise doing with teak, for most boat work, is using an oil finish. But as that’s not likely to work for you in this application, I’d prime it with a good, clear penetrating epoxy like the System 3 Clear Coat ( link below) worked into the grain with a stiff bristle brush ( cut the bristles on a chip brush down to 3/4" or less in length) or any good clear, low viscocity epoxy. Teak is kinda porous stuff, like red oak, so I’d say a penetrating resin is the best way to start, otherwise you may have problems as the oils work their way to the surface and all. Then you can glass it easily enough. You won’t need much, teak is strong stuff. Do not use Wildly Expensive Shoddy Technique ( WEST) resins, they are pretty miserable stuff for this purpose and most others. hope that’s of use doc… http://www.systemthree.com/p_clear_coat.asp

Thanks guys. Amazing how much wood knowledge is in Swaylocks. Actually I was leaning Ambrose’s way and hoping to go au natural with the teak. If so, how to glass them on the board? Routed slot or hot glue to deck then glass fillets? The board’s done in poly. I have Resin Research epoxy. Thanks again, Rob Olliges

I restored a famous all teak 65’ racing yacht called ORIENT it was made in 1937 with a 85 ft varnished spruce mast .The decks are all deck and the boat has no rot anywhere–teak and bronze last a looooooooong time.The yacht is the dark blue hull in SB you can’t miss it.Teak is oily as stated and can be varnished or cleaned occassionaly with oxalic acid and TSP, or,the 2 part cleaner but they are kinda caustic.Wipe with acetone and give it ten coats varnish!!

I restored a famous all teak 65’ racing yacht called ORIENT it was made in 1937 with a 85 ft varnished spruce mast .The decks are all deck and the boat has no rot anywhere–teak and bronze last a looooooooong time.The yacht is the dark blue hull in SB you can’t miss it.Teak is oily as stated and can be varnished or cleaned occassionaly with oxalic acid and TSP, or,the 2 part cleaner but they are kinda caustic.Wipe with acetone and give it ten coats varnish!!

Uhmmmm…only prob with going au natural is that teak or any wood will take up water if it’s not sealed, so glassing 'em on will eventually fail. I’d be a skosh more comfortable with at least a layer of cloth over it, just to give a little protection from abrasion, sand and such, that’d wear through the sealing. I’d think resin research epoxy will work fine, it’s thin enough to laminate with so it oughtta be thin enough to penetrate the surface a little. hope that’s of use doc…

we use smith’s sealer for teak and other woods it’s really thin and soaks in deep -makes bonding to oily woods like teak possible.

To go au natural you could do as was fairly common in the 60s to attach your fin. Since it’s teak, first really wash down the fin with acetone then brush on a coat of laminating resin. Wait until completely gelled and look to see if it has “stuck” well. You will no doubt see some flat looking spots where the resin was absorbed into the wood. Brush on another coat and let it gell. Now rout a 5/8" deep slot into your board (as if for a normal fin box) apx. 1/2" wider than the widest part of the foiled/shaped fin and 1/2" longer than the length of the fin base. Pour in resin to fill the slot about 1/3 full, then slip in the fin and stuff glass roping all around the base. Fill the slot with resin to overflow. After it gells, sand and shape around base. Now brush on a coat of resin with a little wax so you can sand it to a beautiful gloss (work from 80 grit up through 1200 grit. So there, no glass on the fin (skeg) - just high gloss finished natural wood and easy to repair and maintain. This was a fairly common way of affixing skegs (fins) in the old days. If you don’t want a resin finish, just brush resin coat the base that goes in the slot as discussed above and leave the wood un touched until finished. Then varnish the wood skeg with a high grade marine gloss varnish. Enjoy the ride!

PS: If you go the varnish route, you’ll need to maintain it regularly with periodic light sanding and re-coats of varnish just like maintaining a teak trimmed boat. As Doc mentioned, the wood will very slowly absorb some moisture, but it won’t work into the surfboard with this glass-on procedure, and since teak is very immune to rot, no worries during your lifetime. Just let it dry out between surf sessions and keep it well varnished.

yeah yea richard Mc you said it!!! but oblige to tool slots in subsurface fin base so the solidifing resin has sumpthin to mechanicly grab a hold of ooooooooooooooboogie with canned heat…ambrose …doo waa diddiy bee waa chik chik chik kafoooooom cha twaaaaannnngg

Marine Silicone Caulk sticks to about anything.I once did an emegency repair with it on a fins unlimited box.We had lost the screw so i stuck the fin in the slot with silicone.We never could get it back out.I wonder if you could just glue the fin into a box using the same method??

I don’t know if teak plywood has been washed etc.,but I made a couple of sets of teak plywood keels with know bonding problems that I have noticed. They look niced. I coated them with lam resin and then glassed them as usual. Mike

We have been involved with teak furniture alterations for custom applications for designers. No big deal really, but from a woodworking stand point, I have found that Gorilla glue works much better than epoxy for wood to wood adhesion of teak. All the comments about the dulling of steel knives and blades are fact. Planner knives go quickly. Cleaning the wood is a must for finishing.

Funny you should mention teak furniture and Gorilla glue. I have a teak steamer chair that came through with a few factory defects and loose pieces and that’s exactly what I used. Now I’m refinishing an older steamer chair, and it’s going to be time to break out the tung oil and Gorilla glue again. hey, you wouldn’t happen to have any sources for the brass hardware they use on those things, would you? I need to replace a piece that went missing on me last year. Thanks doc…

Doc- The Company in town here is Giati, the owner Mark Singer, is the guy who turns it all to gold, maybe search there website for the right hardware. They might help via e-mail as well. I’ll keep thinking on it today and let you know if something pops up. http://www.giati.com/

Many thanks. I really didn’t want to have to cast another one.