mast delamination

[Comet]

recommended glue or epoxy?

thx

[PAR]

You'll have to provide more information to get a reasonably reliable answer. Why has it suffered joint failure? Is the failure in the joint or along the joint? What was the original adhesive? Mast material and construction method? Age, type of use, boat model and year, Etc., etc., etc.

[Comet]

The boat is an unrestored 16' Comet built in the early 40's, the mast appears to be of spruce square stock that has been boxed in with four more strips of spruce. Delamination is only occurring in the first foot of both ends.

I was considering using CPES and MAS Flag Resin.

Thanks!

[PAR]

The adhesive used was likely resorcinol. CPES will be of little use, being only effective if complete encapsulation of the individual pieces is employed. Epoxy is a very good adhesive and could make the repair, but you have to ask yourself, if a mast with 60 year old glue lines should be trusted in anything more then light, casual service. I've seen old adhesives get brittle with much age and they can let go in a sudden kind of way, under load.

[Comet]

Thanks for the reply. I was thinking CPES to seal the end grain but I suppose the new varnish will accomplish the same thing. DAP still makes resorcinol, I know that it's nasty stuff, does it have any advantages over Gorilla Glue, yellow carpenters glue or epoxy.

The previous owner had stored the mast outside with the ends somewhat exposed. This may have contributed to the delamination at the foot and top. After glueing the ends I’m tempted to sail it and see what happens. Do you think that I should wrap sections of it with wire first.

[PAR]

I think you should rebuild the mast. The glue is probably brittle and past it's useful life. I don't like Gorilla Glue, though many swear by the stuff, yellow glue should be used to fix the kitchen chair, not your mast. Resorcinol is a great adhesive, though requires mighty clamping pressure and reasonably controlled environmental conditions. This was the adhesive of choice before epoxy came along. I still use it, because of the very tight glue lines that can be had with the stuff. Epoxy requires a sloppy fitting joint and thicker glue lines, which can be quite visible in a brightly finished piece. You can CPES the ends to seal up the end grain, but it will have limited effect without encapsulation. I'd be inclined to let the wood breath with moisture content changes, by not CPESing the end grain, unless the whole of the stick could be rebuilt and embalmed in goo. No don't wrap the ends of the pole with wire, it will make matters worse quickly. Make the repair with the adhesive of choice (epoxy or resorcinol) and give it a shot. You may get lucky, though it would be a sin to splinter all that good spruce, testing the quick repair idea, when a rebuild could save it.

[Comet]

Thanks again! How do you suggest separating components the mast?

[PAR]

The first thing I'd do it check the quality of the glue lines by slowly driving wedges into the delaminated areas. This (be gentle) will reveal if the glue is spent or you have some localized damage. It's a difficult call without eyes on frankly. I can't see the wood, the glue lines, the damage, etc. I've seen old masts holding together after half a century of service and others fail in just a few years. I use several clues to get an idea of what's going on. Paint/varnish condition and previous application, fastener hole condition, a 10x glass on the glue lines, plus many other investigative techniques, may be employed to get a good idea of the condition of the lumber, glue, construction, maintenance . . .

[Comet]

Thanks PAR, I'll take your advice. Once I get it indoors, or it warms up, I'll start to wedge it apart. If it comes apart easily I'll re-glue the entire mast with resorcinol. If it is sound, I'll just re-glue the ends.

After that I plan to strip, sand, seal (2 to 1 varnish/solvent) and varnish the entire mast along with the boom, whisker pole, rudder and tiller.

[PAR]

Comet, leave it inside for at least a week (longer is better), so she can stabilize to the new environment. Check with your varnish manufacture (or the label on the can) for a thinning ration as 2:1 is pretty thin. I don't think you'll get much sealing benefit from the thinned coat, as the pours of the wood will still have varnish sealing them up, unless you get very aggressive with the sanding. You haven't any idea how much material has already been removed from the stick in previous refinishing, so just knock her down until she's pretty again, then recoat.

[Comet]

Great! Now I can add the mast, complete with resorcinol fumes, to the motorcycle that's already in my living room. lol! Then again, perhaps I'll
sand til that spring day when it's in the 70's,

Thanks again, I'll let you know how it turns out.