wooden mast repair

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viva

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My wooden mast is made up of 8 sections and some of these the glue has failed in sections about a metre in length and the sections have separated. V Small gap if any but the sections flex under thumb pressure. A shipwright has advised me to clean out the joints with a hacksaw blade and then inject some West epoxy with a slow hardener. I have puchased some large bore hyperdermic syringes and needles to achieve this. I will then give 6 coats of varnish. (existing varnish is in pretty good cond.) My questions are 1. Should I add any filler to the epoxy and if so how much? 2. Are you happy wth this approach?
thanks in advance for your feedback
 
You would need to be careful but all you are trying to do is recreate the original bond. It is obviously easier to work on it in sections as you could then get good access but there is no reason why you couldn't get a good bong if careful. I would think no on the filler. You want the injected adhesive to flow into the gaps. You might be able to get a thin applicator to make sure you cover all the wood on both sides. You will then want to clamp it together, strong enough to hold it tight but not so strong as to force all the adhesive out. There was a PBO recently on how to make these masts and I think they used resorcinol as the adhesive.
 
I'd be reluctant o make a partial repair by just putting an adhesive into the cracks. If the glue has failed in several places, it is likely to be about to fail in others.

I have two wooden masts with splitting problems; they both need to have the remaining time-expired glue taken out and the whole mast re-glued. If you have a bird's-mouth timber pattern that may not be as easy as one made up of slab sections.
 
john_morris_uk said:
When I had to re-glue a wooden mast my surveyor said NOT to use West Epoxy as its far to brittle for mast use. He said to use Aerolite or Cascphen (not Cascamite as that is brittle too!)
Click to expand...

Epoxies mixed with a suitable filler like microfibres are not brittle. They are also one of the few gap-filling adhesives, so unless the crack is machined out to take a properly fitted wood spline then there is actually not really a choice, it has to be epoxy. It really does need a filler though. I would clean out the split as advised, lay the mast with split uppermost and then squeegee the epoxy in place using a hot air gun to thin it and make sure it fills the void.
I've never tried it, but it's possible to rig up a vacuum chamber to get the air out of the epoxy mix - a vacuum cleaner and a box with a tube stuck on it. Heating with the hot air gun might work well enough though. You really ought to finish the mast with a UV resistant varnish, as the repaired splits will have epoxy exposed to the sunlight (not much I know, but it might be enough to degrade).
 
If you have partial failure of the glue joints surely that suggests that the glue is failing.

Split the mast back to it's components and reglue. Get pro advice on the adhesive but my choice would be a suitable epoxy with a thickening agent. Talk to West.

Top Tip use lots of big jubilee clips as clamps.
 
TQA said:
If you have partial failure of the glue joints surely that suggests that the glue is failing.

Split the mast back to it's components and reglue. Get pro advice on the adhesive but my choice would be a suitable epoxy with a thickening agent. Talk to West.

Top Tip use lots of big jubilee clips as clamps.
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I agree with this post as the same thing happened with my Mizzen Mast. I attempted to repair the de-laminated areas and was dis-masted the following year in a modest breeze. I found that the glue had pretty much failed throughout the Mast and that it was easy to separate it into its component parts. Ended up having a new Mast made.
 
If it were my mast I would seriously consider separating it back to the individual sections and then re-gluing it from scratch. I know, it's a bigger job than you would have liked but anything short of a complete re-build would not be very comfortable at the back of my head' :(

You see, if there are cracks it means also, besides the obvious glue failure, that water can have entered the mast. How long has it been entering? How much has entered? Did it cause any damage? I'm afraid that the only real cure, and for peace of mind, is to re-build the mast. Sorry if I have been too blunt.

p.s. My adhesive of choice would be a resorcinol like Cascophen because epoxy can soften if exposed to sunlight and UV.
 
isn't scotch glue available any more
epoxy has not always been about.

I agree with others strip it do the job right. I also think john morris had the right advice about epoxy being brittle
 
mtb said:
isn't scotch glue available any more
epoxy has not always been about.

I agree with others strip it do the job right. I also think john morris had the right advice about epoxy being brittle
Click to expand...

Sorry, but not true about epoxy being brittle, and John Morris's surveyor is wrong. I have done Hounsfield tensometer tests on epoxy samples which show that they are in fact quite flexible under steadily increasing load conditions, such as would be experienced when part of a laminated structure. Only when subject to an impact load (as in an Izod test) would the material show any signs of brittle failure, but even so it would perform better than most conventional adhesives. The other advantage over any other adhesive is the ability to fill substantial gaps as it is a constructional material in its' own right, when used with a suitable filler material. That is why I suggest there is no other suitable adhesive for this sort of repair.

I do, however, agree that in this case, a partial glue failure may just be an indication of more trouble in the future, so it might be worth trying to do a complete rebuild rather than localised repairs. If a rebuild is decided on, and the timber can be completely cleaned up then either epoxy or one of the resorcinol glues can be used. UV is not an issue with a glued joint, as so little of the epoxy is exposed given decent workmanship and thin glue lines. Only when it is used to fill significant gaps, or as a surface coating is a UV varnish needed.
 
If the mast were solid then filling a split, ie a shake, might be ok. The filler could be epoxy, or could be something less expensive. It would only be acting as a filler, stopping more water from getting in. But as it's a built mast, the right thing to do is take it apart completely and rebuild it. Pain, but you know it makes sense
 
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