Couple of notes on butyl, which I think makes a great bedding compound for many applications.
1) If you are buying the butyl tape, take a section and stretch it. The good stuff will stretch out to a number of feet without breaking (it just gets thinner, like pulling chewing gum). I've gotten some recently that didn't really elongate but just broke within a matter of inches (I didn't use it). There is also RV tape that looks the same that is called "putty tape" that may not even be butyl tape but will look like it is (although the inferior stuff I got "was" butyl tape).
2) Butyl also comes in a caulking tube, which may be preferable for some applications. It's often marketed as a roofing/flashing type compound. Synthetics seem to be taking over, but the real stuff can be found (I've found Red Devil brand and Ace brand recently).
3) Butyl is actually a bedding type compound and not really an adhesive (like, say, polyurethane is). I think that most bedding jobs on a boat should be just that....bedding.... but there are some jobs for which you want an adhesive, or other properties butyl doesn't have, so just something to keep in mind.
Sunbeam
