Iron Keel Renovation - WS Epoxy vs Barrier Coat for first sealing layer

[Rhodes143]

Hello, This is my first posting to Sailnet, and actually to any forum such as this. I am a new sailboat owner, of a rhodes 19 Keel version sailboat. I am in the process of completely renovating it from hardware to the keel. I have ground down the keel to bare metal and am now debating what to do next. I have spoken to several other owners and received very good information that all is similar to what is typically posted on the internet. Primarily everyone says to use epoxy, then use epoxy with filler, sand, then bottom paint. One individual mentioned that if he were to do it all again he would use barrier coat instead of west systems epoxy as the first coat. What are peoples thoughts on this? As barrier coats have become much better over time, the barrier coats today are pretty much epoxy with water barrier ability and are rock hard. Could this be a better first sealing layer on the iron? I was also thinking of using OSPHO rust inhibitor to hopefully impede future rust development.

Any comments thoughts would be appreciated. Sorry for the length!
Ed

[WesAllen]

If I'm not mistaken the barrier coat is epoxy with a special additive. West System does sell this additive I know because I have some and bought it locally. I don't see why putting it on first would be any better. The main thing is to make sure the cast iron is free from rust and other contaminates. Plus don't make the cast iron to smooth. If the surface is to smooth it won't adhere as good, because this is a mechanical bond.

[Rhodes143]

Thanks for your comments. I was just told that a formulated barrier coat is stronger than West systems when it comes to cracking and chipping. Does adding the West barrier additive add strengthening properties to it. I ground the keel with 16 and 20 grit, it is fairly smooth to the naked touch but it is in no ways to smooth for epoxying I would think. I am leaning towards using interprotect 2000 instead of the west systems I think. After this is used I'll follow up with West Low density to fill gaps and fair.

[SloopJonB]

Originally Posted by Rhodes143

Hello, This is my first posting to Sailnet, and actually to any forum such as this. I am a new sailboat owner, of a rhodes 19 Keel version sailboat. I am in the process of completely renovating it from hardware to the keel. I have ground down the keel to bare metal and am now debating what to do next. I have spoken to several other owners and received very good information that all is similar to what is typically posted on the internet. Primarily everyone says to use epoxy, then use epoxy with filler, sand, then bottom paint. One individual mentioned that if he were to do it all again he would use barrier coat instead of west systems epoxy as the first coat. What are peoples thoughts on this? As barrier coats have become much better over time, the barrier coats today are pretty much epoxy with water barrier ability and are rock hard. Could this be a better first sealing layer on the iron? I was also thinking of using OSPHO rust inhibitor to hopefully impede future rust development.

Any comments thoughts would be appreciated. Sorry for the length!
Ed

If the highlight refers to my post, I didn't mean to put the Interprotect on the bare iron, I meant after the FILLING had been done & faired. I'd use epoxy resin on the bare metal.

[mitiempo]

Virtually and normal additive to epoxy will strengthen it with the exception of the light fairing additives. I'd go with whatever is less expensive.

The key is to do it on a dry day and the first coat on the iron keel has to go on right after the sandblasting or whatever method is used to get to bare metal. It will start to oxidize in an hour or so.

[celenoglu]

Use only epoxy for coating and do not use low density fairing. this is not a good alternative for underwater use. Instead use glass (sanded down glass fiber) mixed to epoxy for fairing.

[mitiempo]

Originally Posted by mitiempo

Virtually and normal additive to epoxy will strengthen it with the exception of the light fairing additives. I'd go with whatever is less expensive.

I didn't mean the least expensive filler. but whichever is less expensive between epoxy or Interprotect 2000.

Colloidal silica is a good thickener for underwater use.

[sailingfool]

I've done this job three times with West System epoxy, including a R19. West System is the way to go, as it is much harder than Interprotect, and will protect steel much better. Apply directly to freshly ground metal. Five coats is good. Use microballons for filler, it is much easier to sand than colloidal silica. Put the final coat of epoxy over the filler.

Interprotect is formulated for easy application over large areas ( the hull) and ends up being a little soft, you can crease it with your fingernail. Good for the hull, but not for steel.

[Rhodes143]

Thanks sailing fool, so you are recommending to wet on (no fillers) 3-5 layers of West then add the filler compound to fill in remaining voids. Then do one final wet layer?

[sailingfool]

Originally Posted by Rhodes143

Thanks sailing fool, so you are recommending to wet on (no fillers) 3-5 layers of West then add the filler compound to fill in remaining voids. Then do one final wet layer?

Sounds right, just be sure the first coat goes on a freshly ground, bright white metal base.

See Surface Preparation