: I built a stitch & glue kayak and glassed the hull using WEST epoxy.
: Despite touching up wear points with epoxy, I have small patches on the
: bottom chines where the glass has worn through and touch-up resin will no
: longer adhere to the ply which has locally turned grey.

: On these patches the water weeps under the touch-ups and the resin blisters
: and comes off in a month or two. A couple of years ago I put a new West
: epoxy gloss coat on the hull but that hasn't solved the problem.
: I have now stopped using West due to problems with unpredictable curing time,
: surface hardness and the amine blush.

: As the original glass job was a bit lumpy and I never sanded it completely
: smooth, I am considering sanding and painting the hull with Perfection 709
: 2-part polyurethane yacht paint which I originally used on the deck, so I
: will be able to hide any patches.

: The boat was originally an experiment, so little time was spent on cosmetics
: (I regret that now), but I like it so much I can't bring myself to scrap
: it even though, like me, it has gained a few pounds over the years. My
: intention is to make a strip version in the next year.

: I would appreciate any advice on repair or renovation of the bad patches.

: Dave.

If the wood is discoloring, it is probably due to oxidataion, which also means that water is getting into the wood. this is not good.

you will need to sand off all of the wood that is discolored,and smooth that in wiht the sourounding glass. I would sand to about four inches sourounding the glass at least. make sure that the wood is dry before continuing (more on that later) you may want to let it sit for as much as a month before continueing. you will probably want to use a 60 or 80 grit paper, anything smoother will just heat up the glass.

If you've sanded off some wood, it means that you've sanded off a fair bit of glass as well. you should be able to see where the glass sanding ended. (kinda like cutting wood at a severe angle to the grain). you will want to rough up the epoxy to about 3 inches outside the outer part of the sanded off glass. Glass needs about one inch to achieve full strength, the other two is for fairing out flat.
expoxy some glass to the roughed section, you may want two layers. epoxy, fill and fair as normal.

if there is a substantial amount of water soaked into the wood, then this may continue to rot even after the glass has been applied. you either need to dry it out completely, or apply some sort of fungicide. The problems with the fungicide is that it is either verry staining, or is waxy and will cause the epoxy not to stick. If you are going to paint it the staining part may not be too bad.

Another option is to cut out the exposed wood and replace it with strips of wood, then patch like above.