Keel paint

[Juggler7823]

When I had my keels shot blasted around 10 years ago, I painted them with 6 coats of VC Tar. Its now time to paint them again but VC Tar has disappeared from the market, H&S concerns apparently. The only possible I have been recommended is Primocon which I have used for patch painting but has had disappointing results. Th boat sits in a very soft but abrasive mud at low water.

Has anyone got any (sensible) suggestions for an easily available but effective replacement?

Roy

 

[nedmin]

I,ve had good results on my steel boats over the years with Jotun Vinygard costs about £30 for 5lts.

 

[Clyde_Wanderer]

Last winter a friend gave me something like G12? not sure if thats the correct name for it, it was a clear varnishy type liquid which sets rock hard like glass.
I put on a few coats of it on the prepared keel and then several coats of Primocon primer, the metalic grey stuff, before antifouling it.
The keel was fine when I lifted out, although it was a very short season for me.

 

[Impaler]

Is this it?
http://www.mailspeedmarine.com/ProductDetails/mcs/productID/102314

 

[gjeffery]

I have thankfully moved into deeper water and want to make a job of retouching my keel this year.

I plan to grind back the rust patches on the lower keel, and then repaint. I am contemplating primers. Does VC Tar contain any rust treatment agent, or iwill it seal in any rust with moisture to restart the process? Has anyone used Hammerite Red Oxide primer, which apparantly contains a rust converter, as a keel primer?

I would be grateful for any comments!

 

[sailorman]

international Primocon

 

[Juggler7823]

In my original post I asked for info for paints other than Primocon. Primocon is soft and not resistant to abrasive mud.

 

[savageseadog]

Leighs do a vinyl primer called Resistex and there is another product called Limpetite. These products form a conformal coating around the steel which will prevent the paint bubbling up through electrolysis and/or osmosis (yes osmosis). Primocon seems too porous to me but I might be mistaken

The main issue with primers is coating thinkness in my opinion.

 

[Pasarell]

I believe Primocon is a vinyl product like the Jotun and Leighs products mentioned. All will break down in abrasive mud quite quickly although, as Savageseadog says, the most common cause of keel primer breakdown is lack of film thickness. You really do need quite a few coats to give adequate protection. The vinyl primers are really designed for use where good preparation is not possible. If you are abrasive blasting it is worth putting a good primer on. Tar based epoxies are no longer available due to H&S - they were deemed carcinogenic. Most of the big companies now have synthetic alternatives to tar but in my opinion they are not as good unless preparation is perfect and that is not really possible on cast iron. The conventional route now when blasting is to use an epoxy primer but you will be limited on temperature and humidity which are difficult to get right in winter. The temperature you need to note is the surface of the keel, not air temperature and it is unlikely to get high enough for most epoxies before April at earliest.
Whatever primer you use make sure you work it well into the surface pits and voids to get complete contact with the metal. Any air pockets will allow corrosion to set in again very quickly.
Finally, I would avoid anything that says rust converter or red oxide on the label!