We've found the best way to remove old varnish is with a heat gun (my wife uses a Makita). Play the heat on the varnish until it starts to bubble and then scrape it off with a scraper made for this purpose. If you're going to do it with the uncracked steps in place you'll need to protect the surrounding fiberglass from the heat. My wife uses a piece of old formica about 12" square as a heat sink, keeping it up against the fiberglass behind where she has the gun aimed. Keep the gun moving and the nozzle pretty close to the surface you're stripping. As soon as the varnish starts to bubble take the heat away.
If you're going to remove all three steps I would use the same heat gun method only now you won't have to worry about shielding the surrounding fiberglass from the heat. You can sand the old finish off, too, but you inevitably remove a bit of the wood in the process, which is why we prefer the heat gun method.* There are chemical strippers, too, but not only are they not so hot for the environment if they get away from you, they're invariably a mess to work with and clean up.
We use Dolfinite to bed all the external teak on our boat (that we remove, refinish, and replace) as well as other items like window frames because it's a great bedding compound and makes it very easy to remove the piece later if we have to. But Sikaflex is good too, or 3M 4200 (don't use 5200--- you'll be able to lift the boat up with the step).
When you're ready to re-install the steps, fit them in place without bedding compound (put the screws in if it's necessary to hold them in position) and tape off the fiberglass, the step tread, and the supports under the ends. In other words, everywhere there is a joint between part of the step and the fiberglass there should be blue tape on either side of it. Then remove the step, apply the bedding to the step or the fiberglass, install the step, screw it down tight, and using a popsicle stick remove all the excess bedding material that squeezes out of the joints. Then remove the tape.
Depending on what bedding material you use, you may have to remove the tape right now since the material might set up very fast, and you need to get the tape off before it does. Otherwise removing the tape can pull some of the sealant or bedding compound out of the joint. There is no problem in this respect with Dolfinite, but there is with Lifecaulk and some of the other sealants I've used in the past.
The best thing you can do to natural teak is let it go silver-gray and keep it clean. I was taught (and have also read) to use cold salt water and Lemon Joy. NEVER scrub the teak with the grain if you can possibly avoid it. NEVER powerwash it, and NEVER use a stiff brush on it. Teak has tiny veins of softer wood cells running through the harder wood cells and the cleaning "techniques" I described above will remove the upper layer(s) of soft wood cells in these veins. At first you won't see this but as the wood weathers (or you keep scrubbing over time) the softer wood will wear away faster and faster and the tiny crevices you've created will get deeper and deeper and deeper to the point where they look like deep cracks. This doesn't happen overnight, of course, but the first time you go with the grain with a stiff brush or use a powerwasher you''ve started an irreversible process.
-- Edited by Marin at 21:19, 2008-10-30
