Priming a Keel

[mudtertel]

Hi all ,I have a question for anybody who will read this. I have a 25.5 Hunter,it has a cast iron keel , it's pretty rusted up.I'm going to chip and wire brush it , maybe do a light grinding. I have bond-o ,I wasd thinking about covering the whole keel and then painting with anti foil. The question is , will I be able to do that or what should I do.
Thanks , Mike
PS:The boat will be in salt water[/ATTACH]

 

[Dan Johnson]

Mike...

The keels of H34's are also cast iron. Every spring I grind down rust spots to bare metal, wipe clean and immediately spray with a metal primer then immediately coat with bottom paint as soon as the primer is dry. Using a small 4" grinder makes this a quick and easy chore to do. Others use a barrier coat or other form of sealant before applying bottom paint.

Your Bondo solution would work until a crack in it occurs and water gets under it and creates rust where you can't see it. Also, if I remember right, it is permeable by water (not waterproof). It could come off in a big sheet and you'd be back to square one. (A car body is not submersed in water all the time and is painted and waxed). Better to be able to see the rust and attack it as it occurs each season.

 

[Alan]

Not Bondo

Bondo is a porous material and will not stay there for long. The easy way to prepare the iron is to sandblast it. Then use Petit metal preparation (http://www.pettitpaint.com/catalog_browse.asp?ictNbr=86). Then use faring compound to smooth out the rough spots and give a fare shape.
Finally a couple of coats of anti foulant paint.

 

[Joe Mullee]

I Do Same As Dan

Only every other year. Grinding out the rust and adding a sealant takes me between 1-2 hours for each side of my keel (H34). Then it gets painted right away. It never takes longer than 4 hours to do the entire job.

I checked into sandblasting only one time, in 2002. The price in the middle Chesapeake was $1200 back then. Alan is right when he says it's the way to go but it's pricey too.

I was also told by another sailor (maybe read it here) that the amount of rust damage done to the iron keels is negligable from year to year as long as you go thru the process Dan describes no more than every few years. It was said that 5100 lbs of iron will be around long after I'm gone regardless of what I do or don't do.

Good luck.

 

[Alan]

Joe

The nice thing about sandblasting is that you can easily do it yourself. If you don't have it you can rent the equipment and do the job in an hour or so.

 

[Dean Strong]

Do it right and you'll never do it again. Follow Interlux instructions: Grind with 36 grit wheel to a bright shine. Coat with Interlux 2000E within one hour. Follow with four coats of 2000E per can instructions. You can also use West System epoxy, with metal primer additive. It's a little easier to use if you purchase the pump sets. Basically you are applying epoxy over clean bare metal.

Follow with bottom paint. If using ablative, coat while paint is still tacky or it will fall off.

Did mine seven years ago, about 40% of the keel. No rust since.

 

[Warren Milberg]

I've had really good results using POR-15. It comes as a kit to clean and prep the iron, and coat it with POR-15. See url for details.

http://www.stoprust.net/