How to fix my mast

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I have a hollow wooden mast that is square and made up of four sections (one on each side) its 50 years old made of Sitca spruce.

This summer some of the seams have opened up which I have managed to fix with epoxy to get me through the season.
I now need to re-glue the seams. I guess the best way to do this is to break the whole thing apart and reglue not an easy job for me so I've thought of a plan B.

Not all of the seams have gone and the seams above the spreader are sound (although I've only inspected whilst hanging from the top).

Plan B....

Use as thin a saw as I can find and cut down each of the seams one at a time in maybe 1 meter lengths then glue as I go.
I would need some sort of gap filling glue to fill the saw cut so I thought I could use this flexible epoxy.
http://www.westsystem.com/ss/tough-flexible-g-flex-offers-superior-grip/

Doing plan B would mean I don't have to buy or find 300 clamps and would only need to do the areas that require attention which is basically the bottom half between the goose neck and spreaders. I would also not have to remove the goose neck and top fittings or worry about getting the thing back together straight.

Any thoughts on above would be appreciated.

Jim
 
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Hi Jim

In my opinion there are only two successful ways to repair this. I certainly would not go down the route of using the saw blade and trying to glue in a spline in as that will not be entirely successful and to be honest, will probably look a bit of a mess.
The first alternative is, as you said completely take the mast apart which is time consuming and never quite as straightforward as it appears. The other successful method is to set a router up on a jig if it is a round mast or use a fence if it is still basically square section and using a parallel Cutter rout a channel exactly on the glue line. Produce a spline of exactly the right thickness and merely glue it in. Accuracy is the most important asset in this job particularly when routing the channel. In these cases I run a router using a 6mm parallel Cutter down first and then set an eight mm Cutter to run down the already partially cut channel as this cuts much easier the second time without fear of wandering or coming off the line. The new spline glues successfully because it is going to new virgin timber.
Take the time to set the router up correctly, if the mast is square section G cramp a thick batten to the side of the mast with the top edge at the same height as the face of the mast so the router has a flat even base & use the batten as the fence.
If a rounded mast you have to make up an auxiliary fence that cramps to the mast, similar to 2 lengths of timber screwed together to create an L section which is then cramped to the mast.
hope that helps

John Lilley
 
Hi Jim

In my opinion there are only two successful ways to repair this. I certainly would not go down the route of using the saw blade and trying to glue in a spline in as that will not be entirely successful and to be honest, will probably look a bit of a mess.
The first alternative is, as you said completely take the mast apart which is time consuming and never quite as straightforward as it appears. The other successful method is to set a router up on a jig if it is a round mast or use a fence if it is still basically square section and using a parallel Cutter rout a channel exactly on the glue line. Produce a spline of exactly the right thickness and merely glue it in. Accuracy is the most important asset in this job particularly when routing the channel. In these cases I run a router using a 6mm parallel Cutter down first and then set an eight mm Cutter to run down the already partially cut channel as this cuts much easier the second time without fear of wandering or coming off the line. The new spline glues successfully because it is going to new virgin timber.
Take the time to set the router up correctly, if the mast is square section G cramp a thick batten to the side of the mast with the top edge at the same height as the face of the mast so the router has a flat even base & use the batten as the fence.
If a rounded mast you have to make up an auxiliary fence that cramps to the mast, similar to 2 lengths of timber screwed together to create an L section which is then cramped to the mast.
hope that helps

John Lilley

+1, this is exactly how I did my mizzen mast over the winter, I used a tungsten carbide parallel 8mm cutter, down about ten of the seams, let in the splines with epoxy wetting the grooves out first, then thickend expoxy, tapeed in splines allowed to set, planed and sanded off, now the masts are coelans covered, cant distinguish the splines and a strong mast agaion.
 
Ten years ago my mast went the same way plus one of the scarfed joints came apart.
Whilst these days I would use epoxy I glued using resorcinol two part resin glue.
Where the seams were wide open I cleaned them with sandpaper and clamped and where they were slightly open a hacksaw.
Rightly or wrongly primarily I clamped by way of through bolting with m10 threaded rod.Once glued I filled the holes with glued dowel plugs.
 
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