Thus far in the project I have used silicone to bed all the hardware. I prefer silicone to polysulfide (Thiokol and BoatLife Life Caulk) and polyurethane (3M 5200) because the latter two tend to harden in the tube rather quickly. Unless I do a good deal of work in a two or three day period I waste much of these expensive compounds. In addition, the polyurethane is very runny and messy and rather more aggressive as a glue than I like for bedding hardware that may need to be changed or moved in the future. But silicone is far from perfect. It can become separated from bolt shafts and even from the joint between hardware and the deck. I generally assume that about 2 in 10 bedding jobs carried out with silicone will result in leaks that require a do-over.
This is why I have recently been won over by the arguments presented by those who use butyl rubber (see
http://forums.sbo.sailboatowners.com/showpost.php?p=705340&postcount=1). I employed the butyl to seal one of my opening ports. These ports are the old style with a flange that is inserted from the inside of the boat. Then a finishing ring is through bolted to the outside with bedding all round the flange.
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| The Port Opening in the Cabin Wall |
The flange is first wrapped with the butyl. Then it is inserted in the port opening in the side of the cabin. A segment of butyl tape is rolled into a thin strand which is wedged into any gaps between the hull and the flange from the outside. A small string of butyl is also wrapped around each bolt where it exits the cabin wall in a hole that has been chamfered. Finally the finishing ring is tightened in place over the butyl and any excess is pulled away.
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| Butyl Tape Wrapped Round the Port Flange |
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| The Chamfer Bit and Resulting Chamfers |
