For the winter maintenance and upgrading programme in
2010-2011 we decided to re-caulk the deck which, after something like
40 years, was showing signs of deterioration. The main
indications were that the caulking was very thin in places, possibly
only 1 mm deep, and in a very few places it was not actually
present at all. The width of the caulking was also quite
varied - between 3 mm and 4 mm. The teak planks
themselves, however, were generally in good condition, although
certainly worn in some places, but we estimated that the thickness was
still about 10 to 12 mm or maybe slightly more.
The first task was to cut out the old caulking and we decided to do this with a small size angle grinder mounted in a jig which would hold the cutting tool in a vertical plane. The angle grinder needs to have the stop/start button on the 'top' for ease of operation. The cutting tool itself was an 'Arbortech' cutter with three teeth. These teeth are 3.6 mm wide which seemed about right, but with the inevitable slight wandering from side to side in trials, off the boat, it actually cut a groove 5 mm wide which we felt was too wide. We were aiming to make the new caulking 4 mm wide to preserve the correct appearance of the finished deck. Consequently we ground the width of the cutting teeth down to 3.3 mm, but even this made little difference to the width of the grooves that it cut. We therefore ground the teeth down to just over 3 mm wide - the same width as the disc itself. This then cut grooves of about 4 mm width which was what we were aiming for.
The plywood jig made to hold the angle grinder is shown in the photographs above. It must be strong enough to hold the angle grinder firmly as the forces involved in removing the old caulking are very considerable. The centre photograph shows a guide which was added later, but most of the old caulking was removed without this fitted and using it unguided required a fair degree of concentration to avoid wandering off. It was found very difficult to 'start' the cutter on the caulking as it tended to march forward on the rubber, so a short section of the caulking was removed first with the Fein saw fitted with the special attachment for this purpose - see below. In use the angle grinder tends to march forward on its own due to the rotation of the blades so one has to hold it back from doing this. Good lighting and good concentration were needed to keep the cutter on the right path, but it did leave a very clean cut groove. Later on, we fitted the jig with a guide made from 2 mm thick mild steel which can be seen in the centre photograph above. This worked well and enabled a second, cleaning out, cut to be made relatively easily. Whether or not it could be used when the cutter is first run along the old caulking remains to be seen.
The two large bolts at the rear of the cutter enable the depth of the groove to be adjusted. In the winter session of 2010-2011 we did roughly half the deck, about 100 metres of grooves, and the Arbortech cutting blades were fairly blunt at the end of this. For next winter we will grind a new cutter down to 3.3 mm, or 3.2 mm, in width insted of 3.0 mm and this, in conjunction with the guide, may eliminate the need to use the router at all. The angle grinder has the additional advantage that it can pass closer to obstructions, such as the stanchions and the coach roof, than the router.
Most sources suggest making the finishing cut with a router so we organised a guide for this which can be seen on the left below, but we had considerable trouble with the router cutters themselves. Starting with tungsten carbide tipped cutters, with two flutes, we broke three cutters in about 5 minutes so we then changed to cheaper cutters. These lasted well, with no snapping, but actually did not leave such a clean cut as the Arbortech although they did the job of making the grooves look much more uniform in width. The guide worked well, but the router needed to be lifted out frequently to clean out the saw dust. One curious problem with the single fluted blades was that on a couple of occasions the router cutter drilled itself into the teak substrate generating short small troughs which needed to be filled with epoxy. It seemed astonishing that the cutter was capable of pulling itself out of the chuck whilst still being held sufficiently tightly to rotate and cut through the teak.
There are obviously places where neither the angle grinder or the router can get sufficiently close to obstructions and for these places we used a Fein Supercut saw with a special attachment for removing the old caulking. This attachment is a 'sealant removal' tool which works very effectively, but it requires a fair degree of concentration in use. The Fein saw can be seen in use in the middle photograph above, with the sealant removal blade to the right. These blades are available in different widths and we used the 4 mm wide one - part no. 63903184017
One final problem that should be mentioned was that there bronze nails in the grooves holding the teak planks down. The Arbortech cut through these very cleanly, but they tended to disturb the router cutter slightly and had to be punched in afterwards.
The first task was to cut out the old caulking and we decided to do this with a small size angle grinder mounted in a jig which would hold the cutting tool in a vertical plane. The angle grinder needs to have the stop/start button on the 'top' for ease of operation. The cutting tool itself was an 'Arbortech' cutter with three teeth. These teeth are 3.6 mm wide which seemed about right, but with the inevitable slight wandering from side to side in trials, off the boat, it actually cut a groove 5 mm wide which we felt was too wide. We were aiming to make the new caulking 4 mm wide to preserve the correct appearance of the finished deck. Consequently we ground the width of the cutting teeth down to 3.3 mm, but even this made little difference to the width of the grooves that it cut. We therefore ground the teeth down to just over 3 mm wide - the same width as the disc itself. This then cut grooves of about 4 mm width which was what we were aiming for.
The plywood jig made to hold the angle grinder is shown in the photographs above. It must be strong enough to hold the angle grinder firmly as the forces involved in removing the old caulking are very considerable. The centre photograph shows a guide which was added later, but most of the old caulking was removed without this fitted and using it unguided required a fair degree of concentration to avoid wandering off. It was found very difficult to 'start' the cutter on the caulking as it tended to march forward on the rubber, so a short section of the caulking was removed first with the Fein saw fitted with the special attachment for this purpose - see below. In use the angle grinder tends to march forward on its own due to the rotation of the blades so one has to hold it back from doing this. Good lighting and good concentration were needed to keep the cutter on the right path, but it did leave a very clean cut groove. Later on, we fitted the jig with a guide made from 2 mm thick mild steel which can be seen in the centre photograph above. This worked well and enabled a second, cleaning out, cut to be made relatively easily. Whether or not it could be used when the cutter is first run along the old caulking remains to be seen.
The two large bolts at the rear of the cutter enable the depth of the groove to be adjusted. In the winter session of 2010-2011 we did roughly half the deck, about 100 metres of grooves, and the Arbortech cutting blades were fairly blunt at the end of this. For next winter we will grind a new cutter down to 3.3 mm, or 3.2 mm, in width insted of 3.0 mm and this, in conjunction with the guide, may eliminate the need to use the router at all. The angle grinder has the additional advantage that it can pass closer to obstructions, such as the stanchions and the coach roof, than the router.
Most sources suggest making the finishing cut with a router so we organised a guide for this which can be seen on the left below, but we had considerable trouble with the router cutters themselves. Starting with tungsten carbide tipped cutters, with two flutes, we broke three cutters in about 5 minutes so we then changed to cheaper cutters. These lasted well, with no snapping, but actually did not leave such a clean cut as the Arbortech although they did the job of making the grooves look much more uniform in width. The guide worked well, but the router needed to be lifted out frequently to clean out the saw dust. One curious problem with the single fluted blades was that on a couple of occasions the router cutter drilled itself into the teak substrate generating short small troughs which needed to be filled with epoxy. It seemed astonishing that the cutter was capable of pulling itself out of the chuck whilst still being held sufficiently tightly to rotate and cut through the teak.
There are obviously places where neither the angle grinder or the router can get sufficiently close to obstructions and for these places we used a Fein Supercut saw with a special attachment for removing the old caulking. This attachment is a 'sealant removal' tool which works very effectively, but it requires a fair degree of concentration in use. The Fein saw can be seen in use in the middle photograph above, with the sealant removal blade to the right. These blades are available in different widths and we used the 4 mm wide one - part no. 63903184017
One final problem that should be mentioned was that there bronze nails in the grooves holding the teak planks down. The Arbortech cut through these very cleanly, but they tended to disturb the router cutter slightly and had to be punched in afterwards.