Having read the first page or two of this thread, I rushed out and bought some of this wonderful stuff that I knew I could get cheap from home depot. After I messed around with it a little, I came back and read the whole thread. I have now received two rolls from Maine Sail and the HD stuff will be used when I re-work my carport, not the boat!
There is a HUGE difference between the products. If I did not know they had the same base, I would not believe it. The Home Depot stuff is more like plumber's putty. It will fill the gap but not take a whole lot of movement. When it is compressed, it does not stick and elongate like the stuff Maine Sail is selling when things are moved and pulled apart.
Maine Sail, you DE MAN! Thanks!
Yep I went through the exact same process. I tried ebay and found something that's close. And then I tried McMaster and bought "Stay-Soft Glazing Rope":
"Easy to apply, this butyl rope seals leaks in ridges, eaves, gutters, and headers. Also holds glass in frames for a weather-tight seal. To use, uncurl rope and press in place. It stays soft and pliable for years. Application temperature range is –40° to +95° F; operating temperature range is –40° to +212° F. Diameter is 1/4". Comes in 20-ft. roll. Color is gray. This product is compliant under all state VOC rules in effect on October 1, 2008."
It's also close. But it never quite felt like how it was described here. So finally I bought some from Maine. His tape is softer, stickier, and comes in a nice thin tape form instead of round.
This stuff is similar to epoxy in that it all has the same base but still has be formulated just right for specific applications. A lot of variations are close but not quite the same. Maine is doing the work of sorting through that and selecting just the right thing.
So I strongly suggest everyone reading this thread buy from him and save themselves the time, trouble and money of working with the wrong thing.