An older sailboat is likely to come with exterior teak trim and interior teak woodwork. Why is teak used? Teak, by incorporation of silicon oxide into its fibers during growth and its oily nature, is highly resistant to weathering, rotting, and insects; hence, it has widespread use on boats. Unfortunately teak is a tricky wood to maintain if you care at all about appearances. This article is intended as a teak primer for novices.
Although some boat owners claim that teak needs no maintenance, teak will eventually weather and as part of the weathering process, the grain will become raised on the surface. If the grain is raised, the teak will be impossible to finish well, as the raised grain will trap dirt and mildew and prevent the finish from adhering. This can also result in black growth under the finish in warm and humid climates when the teak is finished.
As bare teak weathers, it will first lighten and then turn grey. The first step in aging is often prized in finished furniture since it gives somewhat dark new teak a more golden color. Some people also like the grey color of weathered teak, but that comes only with bare teak, which eventually leads to raised grain. Teak with raised grain should be sanded smooth andbrightened before refinishing, and hope-fully after sanding you will have enough teak that you won‘t have to replace it. (More on brightening later.) Should you have to replace your teak, prime Burma milled teak will cost you a pretty penny (about $90 a board foot). There is cheaper stuff, but it looks like fir. Needless to say you probably can‘t afford not to maintain your teak.
Teak finishes have come a long way from teak oil, which had to be applied frequently on the exterior teak. Synthetic exterior stains like Cetol can last a year between touch-ups. There are a number of similar products on the market and a number of reviews of these products, so I won‘t go into these but will focus on teak interiors.
An older boat with some teak in the interior probably has teak protected with an old fashioned teak oil finish, similar to that from WatCo or from various manufacturers making a penetrating Scandinavian-style‖ oil finish. (The Deks Olje product is no longer made.) The beauty of this type of finish is that it enhances the golden color of older teak, but it takes many coats to produce a semi-gloss finish. However, the old finish can be touched up almost indefinitely.
What are some tricky aspects of teak? Well, first there is the color of new teak. Freshly milled teak will be darker than your typical aged interior teak, and you can‘t hope for a color match in replacement teak until the teak has aged and lightened for a year or two. Commercial teak fillers are also the wrong color for aged teak. They approximate freshly milled teak but are the wrong color for teak once it has aged. Also, because new teak is oily, you should not attempt to bond it with epoxy or poly-ester resin without treating the surface first.
Given that commercial teak filler is the wrong color, what is the right color to use for teak if you need to fill holes? The answer is that there is no one correct color to use. The color of aged teak depends on the amount of end grain exposed on the board surface. The open grain of teak is dark and if open gives the teak its dark color. Moisture will also give teak a dark color. The grain of new teak is open, but closes with aging.
You can experiment with this color change. The first part of a two part teak cleaner will first open the grain of the teak. This causes the wood to become extremely dark. The second part will neutralize the acid of the first part and close the grain. In the process of teak cleaning, any graying of the teak surface will be re-versed and you will end up with brightened teak with any graying removed.
If you have to fill holes or imperfections in interior aged teak, you should color match. Wait until the color of any new teak stabilizes. A color matching system that I use for interior teak uses DAP acetone-based golden oak filler, Ipswitch pine oil stain, colonial maple oil stain, and English chest-nut oil stain. The oak filler should be applied and sanded smooth. A mixture of ipswitch pine/maple/chestnut stain should span the spectrum of teak colors you will encounter. I first mix the maple/chestnut in a 1:1 mixture. That should give the darkest stain you will need. Ipswitch pine on golden oak filler should give you the light-est stain you will need. A color board that starts with ipswitch pine on golden oak filler and increases the amount of maple/chestnut in successive panels may help you decide on the mixture ratio to use for a particular spot. Start with a 64/1 ratio ofipswitch pine and maple/chestnut mixture. Then double the amount of maple/chestnut in each successive panel. Be careful to use the same grit in the preparation of the filler panels as you would use in your actual touchup. Hint: in a small touchup, try for a somewhat darker color in the touch up than the average of the sur-rounding wood. The darker color picks up the dark grain on the surface and looks like a small knot in the wood, which we are accustomed to seeing, and is not as noticeable to the eye as a light patch.