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Old 04-21-2012
EricinToronto EricinToronto is offline
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Questions about barrier coat on steel keel, and sealing keel joint

Hello everyone,

I have a 1973 Grampian 26 (Wind Dancer - Hull 604) we keep in Lake Ontario. I am in the process of applying a barrier coat of epoxy to the steel keel. We - my boat partners and I - noticed when we bought the boat that the keel was 'bubbly' in certain areas - the previous epoxy was ruptured in small patches, and flaking off. Nothing too serious, but it looks like something we didn't want to leave too long. So we decided this year to scrape the steel keel clean and re-apply a barrier coat.

About 80% of the epoxy looked fine, but there were patches where the expoxy had been compromised and was letting water in, to rust the keel. A grinder and some 36 grit disks - as per Don Casey's instructions in 'This Old Boat' - got us to bare metal in about a day. We still need to remove small dime-sized patches of epoxy, brush and clean with solvent, and we should be ready to put on several barrier coats.

While I have epoxied a bare fibreglass hull before, I wanted to get some second opinions about a few specifics of this job. Here goes:

- I understand that we want to apply the epoxy to bare, clean metal wherever possible. But we have a specific area in the middle of the keel, where the keelbolts are, that has a thick coat of epoxy that appears to be good. This extra-thick layer runs between the keel and the fibreglass hull. My plan was to apply the epoxy to this existing coat, sanding and cleaning the older epoxy layer to get a good bond with the new. I am concerned about removing what appears to be a good coat, and potentially messing up the fibreglass/whatever sealing work the previous owners did.
My question: can I apply a new coat of epoxy over sanded/cleaned epoxy and get a good seal? Or will I get water infiltrating between the two layers? Do I need to sand down to bare steel and bare fibreglass?
- There was a strip of sealant added where the steel keel and the fibreglass hull meet. In most places, it was compromised and allowing water to seep in. My understanding is that I need to removed the old sealant, clean/scrape the surface and apply 3M 4200 or Sikaflex 291.
My Question: Do I clean the area and seal the joint, then epoxy around (not over) the sealant? Or can I epoxy over this sealant?
- Don Casey recommends Interprotect 2000E for this type of barrier coat. Any experiences with putting a coat of 2000E on a steel keel, or West System epoxy?

Thoughts on POR-15 to inhibit rust?

Any advice in dealing with the stell keel / fibreglass hull join? Any advice or cautionary tales appreciated.

Pictures of the keel joint and the thick epoxy around the keel attached for reference.
Attached Images
File Type: jpg keel-hull-join.jpg (29.7 KB, 12 views)
File Type: jpg thick-keelbolts-hull-join.jpg (35.9 KB, 12 views)
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