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Ali B
01-26-2016, 03:50 AM
My boat is a 1962 classic teak carvel hulled twin screw ketch. In very good condition but the previous owner used trowelling cement,then loads of sandpapering before painting to give the hull an almost car showroom finish. It looked great until tiny cracks started to appear at a lot of the seams. At the end of the season all the work had to be done again. I have no problem showing that the hull is planked. Two seasons ago I used Saba caulking which remained flexible and could be sanded and painted. I now can not find a supplier of Saba. What is the best product for filling the seams above the waterline? Is a polysulphide product better than most? I would use a primer first after raking out any open seams then gun in whatever mastic type product is the best on the market before fine sanding and then painting with Toplac. When I used Saba I left the seams slightly concave and even after a season in Scotland most of them were still OK. But there are more that need attending to this season.
All help and advice much appreciated.
Ali B

slug
01-26-2016, 06:04 AM
Teak is difficult. Oily ...hard to keep paint or any compound adhered to it.

best seek out a teak hull specialist for suggestions.


http://www.saba-adhesives.com/en

you might reference the Saba compound that you used ,then search for a similar product

Ali B
01-26-2016, 01:52 PM
Thanks for that, Slug.
The teak is not the problem, it is in perfect condition and I am OK about using a primer first - that is important when working with teak. Also, in my original post I suggested that I would gun in the compound, that might give the impression there is a large gap between the planks. There is only a very small gap between the planks and the last few times I have done this work I used a spatula/scraper to work the mastic in. This is purely cosmetic work. The hull does not leak. I have been in touch with Saba and they told me they no longer manufacture a suitable compound. I am trying to use members experience to find the very best mastic on the market for what I need.
Thanks

Bob Cleek
01-26-2016, 07:38 PM
Teak is difficult. Oily ...hard to keep paint or any compound adhered to it.
best seek out a teak hull specialist for suggestions.
http://www.saba-adhesives.com/en you might reference the Saba compound that you used ,then search for a similar product

Well, after owning a teak hull for over forty years, Slug, I gotta disagree. I don't know where this BS comes from. Decent, properly seasoned teak is not "oily." It does have oils in it, like most woods, and often to a greater degree, but properly handled, that is not a problem at all. G-flex is best for epoxy adhesion, as with oak. Beyond that, any good oil based paint or varnish will work perfectly fine.

Well built teak hulls (as most often are, due to the cost, are often fit "tight" without caulking seams at all. This method relies on a perfect fit between the planks and sometimes a bit of bedding compound. Ali, don't go digging up your seams. If they aren't leaking, leave them alone. Do not use any kind of "mastic" or goo! It has no place in seams on a boat. Seams around a bathtub, perhaps, but not a boat. The previous owner did the job correctly (or so it would seem.) The problem isn't your seams, which are always going to move slightly with changes in humidity, but more likely the problem was that the paint he used lacked sufficient flexibility. Many looking for a "car showroom finish" make the mistake of using paints and coatings intended for cars and refrigerators, i.e. for metal,) or which otherwise often lacks the flexibility to accommodate the slight movement of wooden planks, hence that inflexible paint tends to crack along the plank seams.

Maintaining well-done topside job shouldn't require anything more than to apply "glazing compound," "fairing compound," or "surfacing putty" (people call it by different names) in the cracks, the compound sanded fair (it dries very quickly and sands very easily, being designed for the purpose,) the entire topsides sanded lightly to provide a key for the next coat, and two or three thin coats (I'm not going to write a primer on how to paint properly here) of a good quality marine enamel paint. Teak shrinks and swells very little. Other than when a topside is exposed to really a lot of sun and shrinks more than usual, the topsides should look fine for at least a couple of seasons, before it needs another coat. Be careful to ascertain whether a marine enamel is compatible with the finish coat that is now on the boat. Some of the polymer finishes are incompatible with traditional paint. If that is the case, you need to follow manufacturer's recommendations for finishing over it.

Carvel planked boats are not bathtubs. There is no place for flexible "mastics" and "goops" in their seams. Such products adhere poorly, or, alternately, so aggressively as to be practically impossible to remove (e.g. 3M 5200.) Paint often adheres poorly to them and, as the planks move, the flexible goop pushes up and ruins the fair surface. This is the stuff you should use:

http://images.jamestowndistributors.com/woeimages/250_250/00001171.jpg

http://www.jamestowndistributors.com/userportal/show_product.do?pid=4154&engine=adwords&keyword=interlux_surfacing_putty&gclid=Cj0KEQiAz5y1BRDZ4Z_K_eGa84cBEiQAtQkeaOD3LY2F eFpPiwsa7aYprMZ6-lfu_IqnfwZl6ZbBifMaAn438P8HAQ

Follow the instructions on the can (reprinted at the website above,) with three exceptions:

1. Use it out of the can and keep a clean putty knife. Use the can top to loosely cover the putty in the can except when taking some out of the can because it will dry very, very quickly. You do not want to be putting lumpy, half dried putty bits back into the new material in the can or it won't spread worth a damn. This product should be stored top down when shelved to prevent it's drying out. (No, they didn't make a mistake and put the label on upside down!)

2. It can be easily thinned with acetone. It will need to be thinned because only a very little is generally needed and, once exposed to air, it will thicken. To avoid waste, put a few tablespoons of acetone into the can, cap it well, store the can upside down. Overnight, the acetone should be absorbed into the putty and you'll be good to go again. Experiment with how much acetone is needed. If you make it too thin, just leave the can open for a little while and the acetone will evaporate and the putty thicken correspondingly.

3. Despite their caveats, Interlux surfacing putty (or anybody else's... It's a generic product, primarily white chalk in a solvent based binder, is all it is.) is easily applied over painted surfaces, although for a high gloss surface, a bit of light sanding to key the surface is probably prudent.

jamo
01-27-2016, 12:21 AM
I had a carvel planked teak hull for many years in Southeast Alaska. When it came time to repaint or re-caulk some of the seams, after caulking with cotton, I used Interlux white seam compound for above the waterline seams. Goes in with a putty knife easily, cleans up with regular paint thinner and can be painted over with great results.

Ali B
01-27-2016, 02:20 AM
Thanks to both Bob & jamo.
I appreciate what you both say, Bob - I think the Interlux Surfacing putty you mention is what the previous owner used. He also owned a boat yard and had no problems with labour costs or getting the boat into a shed. I will need to find out what Interlux white seam compound that jamo used is. I have notion that here in the UK we buy Interlux products branded as International. It will not take me long to find out. My boat is kept on the hard standing during our winter months and putting it in a shed is not an option this year. So all the work is carried out outdoors. Again, I would stress that the hull is in near perfect condition and the seams are very close - there is no question of me needing to rake out the cotton - if there is any - The cracks I mention are what Bob describes as caused by extremely small movements due to the changing weather and humidity. I might well try different products in different places and wait for a couple of seasons to see what is best for me.
Many thanks.
Ali B

Bob Cleek
01-27-2016, 01:34 PM
Yes, I believe Interlux and International are the same company and products, with International sold to the European market. The difference between their "seam compound" and surfacing putty is that the seam compound is intended to be used over caulking cotton to stop the seam. it is slower drying and more flexible and made for filling larger gaps. The surfacing putty dries very quickly, so you don't have to wait for it to dry before sanding and it sands very easily. ("Like butter!") For the finishing you want, it's the surfacing putty that is the proper product. It can also be used to fair small dings and nicks on your topsides before painting.

Ali B
01-27-2016, 04:26 PM
Bob,
I spent some time yesterday on both web sites. They are without doubt the same company both owned by AkzoNobel. They probably don't sell the seam compound in the UK because the market here is so much smaller than USA. I have found some on Amazon and will wait to see what it is like when it arrives. I can get surfacing putty here in the UK. I intend to use both products on different areas of the boat to see what suits our climate best. The boat is so well built that a little experimenting over a couple of years will not make the slightest difference to her. Anyway, the weather right now here in Scotland does not interest me in doing any outside work! I will wait until March.
Many thanks for help and advice.
Ali B