Sikaflex?

[ripvan1]

andrew, this is no way a criticism as I have used your method successfully but recently I found this on a series of how to articles by compass marine - this one dealing with rebedding deck hardware - set me thinking

I am going to inject some strong opinion here so please move on to the next photo if you don't want to hear it. I truly dislike and disagree with the Don Casey "two step", "wait to tighten and form a gasket" method of bedding deck hardware. In my opinion this method is probably one of the leading causes of deck core rot on the planet. Believe it or not but I'm not a conspiracy theorist. I do however feel as if Don Casey wrote that technique to guarantee boatyards future revenue. This is NOT to say that it can't work though. It certainly can. The problem is, can the average DIY or yard employee get repeatable results that are reliable consistently. The answer to that is very often no.
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Think about it? If the sealant cures, to form a "gasket", and you then move the bolt while tightening it down on the "second step".... It leaks... If you create a gasket too thick, and then can't get the mechanically fastened hardware tight enough against the deck, because of compression resistance, the hardware will move, and the sealant will eventually fail, so again.... It leaks..
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Sorry, I mean no disrespect to Mr. Casey, he writes some excellent stuff. Sadly this method is perhaps some of the worst advice I've read in any sailing/boating related book when applied to the average DIY attempting it. I have witnessed far too many cases of core rot due to the DIY & professional "two step" bedding procedures than I would have liked to.

 

[doug748]

I think you have a point.
The key is to close the joint till it is almost there. The final nip, next day or later, should only move the nut.

 

[Salty John]

The professionals recommend that you fit shims or washers to raise the fitting, (cleats and the like), a mm or so off the deck so that when you tighten down you don't simply squish all the sealant back out of the joint. Also makes it easier to remove the fitting because you have space to cut the sealant with a sharp knife.

Tightening down almost completely and then re-tightening after the sealant has set achieves almost the same thing, I suppose, except that the fitting isn't tightened down against something solid. It's what I've always done, however, and never had a problem with subsequent leakage.