Hi,
Look carefully at the top of the toe rail where the plugs (bungs) over the bolts are located. If you see discoloration or darker color around the bungs, this shows water in the wood. I tried to sand and varnish over this, and there was enough water in the wood that it just lifted the varnish off about a year later. It was really gross. The varnish was intact, but you could see the water bubbles under it and push it around with your finger. Cut the varnish, and out it came. So, with this in mind and the experience of others, I would really recommend removing the toe rail to do it right (and only do it once). I know this is a big job, but I've resigned myself to doing this one day soon. In the meantime, I have gone back to oiling the toerail to try to displace water and prevent further intrusion. The other problem I see is that the wood will wick the water up from the deck side where the bedding compound has failed. I think you are doing so much work to make her nice that you don't want to run a bead of caulk on the sides, but remove it and put it underneath. In any event, don't use epoxy to seal this. It will not flex enough and I think will ultimately leak again.
Look carefully at the top of the toe rail where the plugs (bungs) over the bolts are located. If you see discoloration or darker color around the bungs, this shows water in the wood. I tried to sand and varnish over this, and there was enough water in the wood that it just lifted the varnish off about a year later. It was really gross. The varnish was intact, but you could see the water bubbles under it and push it around with your finger. Cut the varnish, and out it came. So, with this in mind and the experience of others, I would really recommend removing the toe rail to do it right (and only do it once). I know this is a big job, but I've resigned myself to doing this one day soon. In the meantime, I have gone back to oiling the toerail to try to displace water and prevent further intrusion. The other problem I see is that the wood will wick the water up from the deck side where the bedding compound has failed. I think you are doing so much work to make her nice that you don't want to run a bead of caulk on the sides, but remove it and put it underneath. In any event, don't use epoxy to seal this. It will not flex enough and I think will ultimately leak again.