: have now started to grind the coating off of the bottom. It is a sickly
: yellowish color, and very hard to grind. Any idea what it is?

Yellowish would make me think of UV pollemerized resin, but that should be easy to sand.

: recomendation on epoxy type to use to coat the bottom. I am figuring on
: three coats, and two small patches. Been looking at system three epoxy,
: look like a good brand to me. Thanks much!

Epoxy selection is probably second only to kayak selection for the holy grail (of kayak building) discussions.

At a fundamental level all common epoxys will do the same thing, and you should be satisifed with whatever epoxy you choose.

That being said, according to some side-by-side comparisions, system 3 (which is my favorite epoxy) placed pretty much in the middle of the pack, without ever being wost or near worst at anything. I.e well rounded. HOwever is is probably best at being able to set while being badly out of measured spec. (you can miss-count, miss-measure, or miss-mix and still have better odds that the epoxy will set up correctly, not that I am sugesting that mind)

good luck