Cracked bowsprit & question on wood adhesives

[S/V Ethan Grey]

I really need to address my cracked bowsprit. I'd rather not replace it just yet as I have other, bigger issues to address. I'm thinking glue and clamps, and possible drilling in a few long screws from the sides. I think that will get me through until next year. This got me thinking about what type of glue to use.

There is a guy that did a test of 64 different wood glues and posted the results. You can check out his video here:
https://www.youtube.com/watch?v=JFEPTPTtFsw&t=1247s

and his data here:
https://docs.google.com/spreadsheets/d/ ... =822163521

His recommendation for outside use is Dap Weldwood Plastic Resin. I wanted to get the forum's thoughts on how to tackles this and if anyone has had success with wood glues for the marine environment.

Thanks!
-david

[ghockaday]

If that is still White Oak, I have read that it did not glue very well but no personal experience.

[John Stone]

David.
I used weld wood plastic resin on my tapered laminated tiller. Has held up well but I keep a sunbrella cover over it when not actively sailing. The glue is water resistant—not waterproof.

There is only one adhesive that is 100 percent waterproof, heat proof, and boil proof. Resorcinol. No other glue that I know of is approved for overhead structures or for building airplanes.

You can use other glues with good success if you protect the glue lines with paint or UV varnish.

I don’t think you can’t buy resorcinol in the US anymore. Aerodux 185 is a new advanced resorcinol. It’s made in Norway I think. PB adhesives imports it. I used it on all my exterior teak glue up—my cap rails, dorade boxes, my sculling oar, etc etc. has not failed and all have been beaten by the tropical sun and drowned in saltwater. Only the cap rail is painted. All the others are bare wood.

Aerodux 185 has some gap filling qualities and can be used in temps to 55° I think. Original resorcinol needed 70° min for 24 hours. Both require precise joinery though aerodux is more forgiving. Weld wood requires 70° I think...or close to it. All three require good clamping pressure.

If you want to learn the real deal on adhesives for boats take a look at Larry Pardey’s wonderful book “Details of Classic Boat Construction—The Hull.” There is a whole chapter devoted to just adhesives. Be forwarded was not a fan of epoxy for exterior wood construction. Many boat builders were not happy with his position. However, none of the epoxy manufactures ever challenged him. He even let West Systems review his work before he published it. They made no changes.

I use epoxy for certain things. It’s a tool. But I don’t use it for exterior wood construction. I would not recommend it for your bowsprit. But if you do, or if you use weld wood, you should keep it varnished or painted.

[S/V Ethan Grey]

John,

Thanks for taking the time on the response. I’ll have to check out the book. I did find cascophen, a resorcinol adhesive at:
https://www.aircraftspruce.com/catalog/ ... cophen.php
And
https://www.wicksaircraft.com/shop/casc ... yes-no-fee

In small enough batches for me to try out. However, since this is a cracked joint and not a planed joint, I don’t think it will work too well. I’ll have to think about it before committing to a solution since if it fails I don’t know how I’ll get the adhesive out of the joint. Who knew gluing wood would be so tricky. I guess one benefit of living in this Florida summer heat is that the temps will definitely be high enough to set the glue. But that means I need to quit procrastinating and make a decision.

[John Stone]

I guess I did not read the OP close enough. I can’t really offer any advice on cobbling a repair together on something like a bowsprit. It’s a structural component. I’d have no confidence in it unless I had to do it to get from here to there for a proper repair. Then, probably epoxy.

Definitely not suitable for resorcinol or any glue that requires tight joint unless you remove it and cut out the cracks and if the rest of the wood is good scarf in or laminate in new wood.

I highly recommend you rebuild it. But if not in the cards you could try epoxy and paint it.

[Frenchy]

As a temporary fix, I would think about opening the crack as much as you can without splitting it further, laying in some epoxy and installing wood screws to pull it together. Then, I'd sand the underside really well and epoxy in another
board that spans the crack, ensuring first that it doesn't interfere with anything. If necessary, the existing holes
could be plugged. Then, as John suggests, prime and paint the whole thing. - Jean

[jbenagh]

I had to build a new bowsprit last winter due to getting hit at the end of the season. I built it almost just like the original. It had 3/8in stainless threaded rod about every 12in. I drilled a 1/4 hole from each side toward the center with a bellhanger bit , using a straightedge to align. Then followed up with a 3/8 bit. For a temp repair you could just use galvanized threaded rod and not countersink and bung the fasteners.



Jeff

[yankeefan]

In combination with the other great suggestions, to add integrity to the edge piece that is split I suggest side drilling and inserting fluted dowel pins in combination with the glue, epoxy and stainless-steel screws. If you can't find long enough fluted dowels, dowel stock from your local hardware should suffice. It would be a very temporary fix until you can replace the bowsprit but should hold everything together and add a bit of lateral strength. I wouldn't be too worried about the material (i.e., poplar, oak) since it's a temporary repair and you’re using a marine glue or epoxy.
The other suggestion I have is to also fill any of the holes seen in your picture with the same dowels or wood and epoxy. This will also go a long way to adding structural integrity.

[Joe CD MS 300]

West Systems has great manuals for using their epoxy and great tech support. All kinds of different fillers for different purposes. It can glue and fill and b3 structural. Epoxy is the standard method for redoing holes for fittings. You just need to protect from UV with a marine varnish or Cetol if exposed to light. I repaired a Teak swim platform several year back and it’s still holding up well. It is constantly wet.

[Keith]

IMHO I would not risk a temporary fix. If this fails your rig is coming down on your head.

Replacing the bow sprit is a pretty straight forward job. I replaced mine a few years back with a single piece of teak from St Angelos in Tiverton RI. I think it was about $350 at the time. The most difficult part of the job may be getting the old on off the deck without delaminating the gelcoat from the glass. This has been documented by several on this site.

Good Luck,

Keith