Cast iron keels

[PaulAG]

Do any of you cognoscenti out there have firm opinions about the best treatment for cast iron bilge keels on my venerable Centaur? I have received two definite but opposing views:
1) use epoxy coatings - several, filling and fairing between;
2) don't try this expensive option as application conditions are critical and all rust must be very carefully removed before application; use the chlorinated rubber-type paints ?keelprime?
3) Will I need A/F primer before A/F?
Also, difficult bit is getting under the keels, or do I just have to do what I can reach, then lift the boat, move the wood blocks and do the uncovered bits?
Grateful for any comments before I start.

PaulAG

PaulAG

 

[Joe_Cole]

The best, but most expensive answer is to use Epoxy. To do it properly you would need to shot blast the keels before painting; then it will last for years. Two or three coats should be adequate, just follow the manuafacturers instructions.

I suppose it boils down to how long you intend keeping the boat.

I don't think my brain is working this morning. What is "A/F"?

Regards


Joe

 

[PaulAG]

Joe, A/F = antifouling - it is Sunday morning!!

PaulAG

PaulAG

 

[Joe_Cole]

Oops. Oh yes!
Red face.

Regards

Joe.

PS. I don't use a primer with my A/F (I'm a quick learner!), but I suppose it depends on what the manufacturer recomends.

 

[alanporter]

Do you really need to completely protect your keel from rust ? The cast iron keel on my 26 year old Westerly Renown gets roughly sanded down, painted with a steel primer, and then antifouling, every second year. There are always some superficial rust flakes to brush off but, looking at the thichness of the metal, I reckon the keel will last longer than I will. Keels are not a cosmetic part of your boat so why worry about a bit of rust ?

Alan Porter

 

[AndrewB]

Yes, I agree.

Cast iron doesn't normally rust that deeply, specially if it's kept immersed. PaulAG will be making a rod for his back by cleaning right back. The only thing I'd suggest is that if there is bare metal showing when he pulls out that it is primed immediately, as it will tend to rust in the air. Chlorinated rubber primer will do fine.

 

[Dipper]

Has any body else used car body underseal?

I used this on an iron rudder for about 6 years with no problems, even coating odd rust patches over the top of existing antifouling.

On my current boat, I have successfully used it on rust spots on the keel, on a steel plate underwater that secures the rudder and on the tops of the keels bolts in the bilges. The antifouling is slightly unwilling to stick at first but doesn't seem to come off. The underseal dries in minutes, is ‘self healing’ and costs a couple of pounds a tin!

/forums/images/icons/crazy.gif


Dipper di doo dah, Dipper di day
My oh my what a wonderful day!

 

[Guest]

when I had a mono, I tried epoxy on one bilge keel and chlorinated rubber on the other. The rubber lasted much longer, to my surprise.

This was on a drying mooring.

 

[snowleopard]

International paints say...

i spoke to one of their techies & he said 5 coats of Primocon before applying a/f. he also said that the quality of cast iron used in keels is such that impurities set up galvanic cells within the metal and it's impossible to prevent rust recurring. i took his advice and primocon worked well with only small spots of rust to touch up after 2 years.