Join Date: Jul 2006
Location: Corpus Christi, Tx
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I have a 1976 Pearson 28 which has windows that seem to be ubiquitous for boats like it (catalina, o'day, pearson, etc). Infact I purchased a reseal kit from Catalina Direct that contained new rubber gaskets and sealants for these windows. The windows are made from an aluminum extrusion that consists of a flange that fits against the outside of the cabin top and three channels one for the glass, one for a trim piece, and one for attaching screws. This is a one piece extrusion that would look somewhat like "luu". On the inside there is another extrusion that clamps the window unit to the hull and hull liner. As recomemded by the Pearson 28 Yahoo group, I filled the space between the cabin sides and the hull liner to make a stiffer clamping surface. My question is about the sealants provided. One is Dow Corning 795 Silicone Building sealant which is directed to be used between the inside surface of the glass and the rubber gasket and then between the inside surface of the rubber gasket and the aluminum channel. The second sealant is 3M 4200 quickset which is directed to be used between the aluminum flange and the outside of the cabin sides.
What I find curious is the placement of the 795 on the inside surfaces of the glass and its rubber gasket. It seems to me that if the rubber gasket alone is insufficient to stop water intrusion this arrangement guaratees that water will be trapped in the glass chanel with no way to exit and given it will be salt water, this could cause serious problems. Am I wrong on this?
Also, based on discussions here about butyl tape for sealing deck hardware, it seems that butyl tape might be better than 4200. This might be expecially true here since there is only about 3/8 inch overlap between the cabin side and the window flange. Which would you use?
Thanks for your help,