A Question of Caulk

[Rich_F]

We've got teak trim on a GRP deck, and a few patches of the caulking are coming loose and need to be replaced this year (the boat is 13 years old). However, I'm concerned that all of the caulking on the deck is standing very proud of the surrounding teak (maybe around 3mm), whereas I had thought that it ought to be flush. I've only recently acquired the boat, so I don't know whether the caulking has always been like this.

Any ideas whether this caulking might have gone like this for a reason, or whether it's likely to be the original state? If it is original, I should probably aim to get my recaulking to match.

But if it isn't original, maybe I should think about flattening it down. Any ideas how best to do this? I've tried using a blade (on some caulking that has to be replaced anyway) and found it very hard to get a clean cut. I've heard that a belt sander works, but I'm worried about that being too aggressive.

Thanks in advance,

Rich

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[pvb]

Are you in a good mood?

Hope you are in a good mood, because you're facing a long and tedious job. I had exactly the same problem with my teak deck. The previous owner had scrubbed them rather too enthusuastically, resulting in the teak being worn away, with the rubber caulking left standing proud by 3-4mm. About a year ago, I finally got up enough courage to tackle it. Here's what to do.

First job is to cut off the surplus rubber, using a small craft knife. There's yards and yards of it, so patience is needed! Next, smooth off the surplus rubber with a small belt sander with medium grit belts, used very gently. Minimum pressure, aligned roughly with the grain of the wood, and keep it moving around so as to avoid excessive removal of wood. Apply masking tape around the bottom of the sides of the coachroof, to protect the fibreglass. Also unscrew any fittings you can, such as windlass switches, vents, hinges, chainplate trims, etc. When sanding, the secret seems to be to strike a happy compromise between having the deck look reasonable whilst not removing too much teak. It's very likely that some sections of caulking will be lifted by the sander - I just cut them off at an angle as soon as they got to a point where they seemed to be adhered to the teak. The sander I used had a dust bag attached, but some sanders can be connected to a vacuum cleaner. It's best to wear a mask, as teak dust is harmful to your lungs.

Then, use a small detail sander (with little triangular sanding sheets) to tidy up edges and around fittings. Then, recaulk the places where the original caulking was removed (use masking tape each side of the groove).

Next thing I did was to wet-sand the deck using a foam-rubber hand-held sanding block, to remove any fine swirl marks.

It was a long job, and one which I'd put off for a couple of years, but in the end it looks much better and I'm pleased with it.

Oh, and knee pads would be a good investment.


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[Rich_F]

Re: Are you in a good mood?

Well, that's just about realized all my worst fears. Thanks!

However, the good news is that SWMBO wants to move the boat to Scotland. "Fine", I said, "once the deck's been sorted out." So she's really keen. Tee hee!!!

Just so that I can really make her day, can you give me an idea of how long this is likely to take (on a 29ft yacht).

Cheers,

Rich

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[Paulka]

Hi! Rich,

The teak is a soft wood, compared to the "black stuff" which probably is, or at least should be some kind of polysulfid. It is hence normal that the wood weared away during all the years.

You absolutely should either cut away, or sand away the excess "black stuff". If you don't, it will be riped of the grooves by the crew's shoes whenever the boat heals.

Both methods you suggest are O.K. To cut it out, you'll need very sharp chisels, wide enough to lean on the timber on both sides of the groove. You probably will need to give your deck a light sanding afterward anyway, to smooth the surface of the timber, and get the nice golden color back.

It's a hell of a job, but very rewarding.

Using a belt sander, use fine sanding paper (180 or 240), and always sand across the grain, to avoid taking away the soft summer wood (or is it the winter wood?), between the layers of hard wood. This way, you will sand timber and "black stuff" level, as it should be.

Have a look here, http://www.yandina.com/TeakDeck.htm
althought not all of the information there will be of any use for you, it's good to know "a little bit more".

Good luck!




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[pvb]

How long?

Difficult to say how long it might take you. Maybe a day to trim off the worst of the surplus rubber with a craft knife - I did it progressively over quite a period because I found it mind-numbingly boring and it made my fingers ache after about an hour. Then maybe another day to belt-sand. Half a day to detail sand. Allow a day to mask and caulk. The caulking needs a few days to cure before you can finally wet-sand, which will take half a day.

But think of the money you're saving by doing it yourself!

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[spark]

A sharp 1" chisel (or the iron from a small block plane) is the easiest tool to use for cutting back the black stuff. Get the angle right (so that the cutting edge is just clear of the wood) and you'll reduce the sanding job considerably.

As others have said, use the belt sander with caution, I'd recommend going at a slight angle (10 degrees-ish) to the grain of the wood/run of the joins. Less chance of stripping the caulking out and/or making waves in the wood.

If you're properly tooled up (and keep the chisel sharp) I don't see why you shouldn't get the bulk of the job done in a day. You might need a second day for the fiddly bits arounf deck fittings, etc.



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