Hey guys,
I'm prepping the bottom of my boat for new paint. Had a crew of friends over helping me sand/smooth down the old paint. One of them got a little agressive on the the keel and got down to the raw iron. Would you guys just slap more bottom paint on it or is there something I should put over that area to protect the metal?
Thanks!!
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'86 Catalina 36
Work in progress!
If you know which type of bottom-paint you want to use, check the available data-sheet of this type of bottom-paint.
Here you can find the makers recommendations for the surface-preparations including type of primers or type of barrier-coats to be used.
Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland
To my knowledge, Catalina never made a 36 with cast iron used in the keel. They use lead, as most other manufacturers do. Bottom paint will not seal the lead against the effects of salt water and over time, water will migrate between the fiberglass and lead- causing additional separation. I would patch it with epoxy and fiberglass cloth, fare it and then paint with the bottom paint. The patch should overlap the surounding gel coat to totally encase the damaged area. Epoxy and/or gelcoat repair paste will not adhere directly to the lead and will flake off after the 1st season.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
That was my understanding as well, but the friend was grinding away at what he thought was rust. It looks like there is some surface rust elsewhere on the keel in a couple of spots too.
Boat-specs.com shows cast iron for the keel: https://www.boat-specs.com/catalina-yachts/catalina-36-mki-fin-keel
Sailboat Data shows lead: https://sailboatdata.com/sailboat/catalina-36
'86 Catalina 36
Work in progress!
If the keel is lead, you would be able to shave a piece off with a knife. If it's cast iron, a magnet should stick to it.
Either material, I would still recomend the epoxy/fiberglass patch approach.
I have a mid 1980's Catalina 36 brochure that states the keel is produced from lead. Interesting that one of your links lists cast iron.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
My preference would be anyhow to use a good primer like International Primacon instead of applying a epoxy layer. You have then always a change that due to damage water can come between the epoxy and the metal - whatever kind it may be - and then you have a perfect condition for pitting corrosion.
Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland
In digging in to the keel issue a bit more I've found that the lead is definitely lead. However, all through out it i'm finding little rust spots with what looks to be iron pellets in the lead. Very interesting.
'86 Catalina 36
Work in progress!
Are the pellets you describe random or are they possibly pins used in the molding process like registration pins?
Couldn't find anything in a search yet. Strange there would be a need for that though. The iron molding process uses some interesting items inside the mold to keep the metal hot and flowing as it migrates into the all the nooks and shapes of the mold. These burn up however and there is no residue.
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Harold Baker
S/V Lucky Duck
Duncan Bay Boat Club
Cheboygan Michigan - Lake Huron
1989 C-36 mkI TR/WK M25XP