So, what was it like? How did it come out?
Having removed all of the peel ply, with some difficulty in places it has to be said, the answer to both those questions is not good enough. So much so that al of the epoxy on the original coper bot will have to be removed.
In a lot of places the result appears to be good.
But in others the epoxy has not bonded to the underlying layer at all.
You can see the extent of the problem quite clearly in this photo. I think that the main problem is that despite hand sanding with 40 grit sandpaper, the key in the copper bot is just not good enough for the new epoxy. The epoxy has stuck really well to those ares of the hull where the copper bot has been removed, the repair for example and the skeg, which had no copper epoxy in the first place.
Using 80 grit sandpaper on a belt sander gives a very good key as far as I can see but the sandpaper is so aggressive that care has to be taken not to go too far through the layers. Under the copper epoxy is another layer of epoxy that encapsulates a covering of glass fibre. I need to key the top layer but no more than that. The above photo shows the result of just a minute or so of power sanding but in several sections that has already worn through to the non-copper layer beneath.
Still, the new epoxy over the copper has to come off. Fortunately, since it is a very new layer, it is very susceptible to heat and comes off easily with heat gun and scraper.
The plan now is to remove all the new epoxy where required and lightly sand the hull and then wait until next weekend when I shall use the belt sander to get a good key and then copper epoxy the hull.
Hopefully this time it will work.