Mahogany splines

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Sniper

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I'd welcome views on how best to repair some splines on my mahogany topsides. Some of the seams need resplining - no problem there, the spline has deteriorated and fallen out so I will just replace them.

However, in some seams the spline is intact and all that has broken is the glue line. Rather than removing and replacing the whole spline, my thinking is to simply brush in a thick epoxy mix and fair up afterwards. What do you think?

thanks
 
I imagine that only one glue line has failed, making it difficult to remove the spline so that it can be cleaned up and also so that a good spread of glue can be applied to the top and bottom surfaces. With the perversity that comes naturally to boats, it will be both surfaces that have failed, but not in the same place. I do not think that a viscous epoxy would brush into the failed seam far enough to be effective. You might get a gelatinous epoxy to run in under some pretty determined trowelling with a spatula, but I would use a liquid form if you are reluctant to remove the splines. The finer the gap, the thinner the liquid should be to get it to wick in.
Peter.
 
What I would do is to rout out the failed glue line with a saw or small router bit, so that you are left with a uniform width groove with clean wood at its sides. Say 1/16 or 1/8". Next I'd buy, or make, mahogany splines of the same thickness as the width of the groove [perhaps with a very slight taper], coat them with adhesive and tap them into the groove. When the adhesive is dry, plane them off flush with the rest of the planking and revarnish.

Your suggestion of trying to brush in epoxy would probably fail because the groove would not be clean enough for a good bond. Also, the wider the glue line the weaker the joint and the epoxy might break up as the boat flexes. I reckon it's best to do the job properly and do it once rather than having to keep re-doing it.

Anyway, that's what I would do but others will no doubt advise you differently.
 
Thanks to both of you for the advice, which looks good and doesn't contradict. I think it is probably one of those jobs that is worth getting right the first time, otherwise it will be a perennial PITA.
 
Best would be to route out the old splines and glue new ones in,i wouldent use mahogany as it tends to tear,Before i suggest another wood i would have to look through my wood book,then ask for opinions hear!!

Why dose everyone wanting to glue something on a wooden boat talk of epoxy-its just that poxy!! It will not stay on a surface that has moisture in it,and almost no wood can have the moisture levers reduced to let it work,

The west systems admited that their product was aimed at new built boats with wood dried in a special workshop,and the system wasent suitable of built boats!

The glue you should use is aero dux or casscomite. Silicon and epoxy arent ment for proper boats.But are found on plastic boats
 
Before you re-spline, ask yourself why the splines have failed. It could be due to glue failiure. If the old glue is clearish and brittle it may be Aerolite, which lasts around 30 years. If this is the approx age of your boat consider resplining the whole of the topsides. Brushing in epoxy really wont work as the gluing faces must be really clean. You could open up the glueline to enable this but if your topsides are varnished it will look a bit DIY when finished. If you decide to respline, use a tapered cutter from Trend (6mm). Setting up a full length batten to guide your router is tricky and you must be accurate (+-1mm) Machine up splines to match. The joy of tapered splines is no gap filling glue is required so you can use resorcinol, polyurethene (great for outside) or .....epoxy in the right conditions.

Other reasons for faliure could be if your topsides are painted a dark colour, and you are not on a swinging mooring, your topsides will be warming up when (if ever!) the sun comes out. This results in moisture content reduction of the planking, shrinkage, and highlights weakening glue lines. Combat this by light pastel coloured (pref. white) topsides, plenty of paint inside and out, and not mooring in a marina!
Hope this helps
 
Hi all

Sorry for my first post to be a thread resurrection but this one is relevant. My boat has a splined hull, painted, not varnished, and the splines have failed in a couple of areas under the waterline. I'm not about to do a full respline as most are fine. The planking is mahogany, but I would not be using that for the repairs, I was planning to use larch which I can get locally.

My question is to do with the glueing and the wood. I'm pretty sure the old splines are in there with resorcinol and I'm totally certain I can't get the hull dry enough to use epoxy, not that I likely would anyway. Since the areas to be repaired are only around 12-15 inches long where fresh water has been allowed to stand, I was going to clean out the old, make up some lightly tapered larch splines, slather on some thinned red lead putty and tap them home for a reasonable (not hard) interference fit which should, when the hull wets, be nice and tight. Obviously I would plane off flush before painting.

Comments on this approach? Trouville, what does your wood book say about using larch in this way?

(BTW my understanding is that splines are normally fitted glued on one side only when the hull is dry, allowing a tight seal when it wets, just FI.)
 
You should be able to get the seam clean enough using an angled seam rake or some 80 grit. I would not use putty, but polyurethene such as Balcoton ar any PU moisture curing glue. Using larch will be fine, cedar would be as good if not better, or Brazilian cedar. I think the point is tou are either going to glue it, or your not. Puttying in a spline is neither one nor t' other. You may as well just putty!
BTW, I have never come across splines glued only on one side. Mind you, I don't get out much!
 
[ QUOTE ]
You should be able to get the seam clean enough using an angled seam rake or some 80 grit. I would not use putty, but polyurethene such as Balcoton ar any PU moisture curing glue. Using larch will be fine, <snip>

[/ QUOTE ]

Cleaning the seam is no prob, it would be the drying. Balcotan is an excellent idea. Thanks.
 
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