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Iron Keel Prep
I was considering doing a full bottom job on my Coronado 41 here in Seattle, but due to the cold snap have decided to hire someone to do the tenting & painting.
I have a 10,000 lb cast iron keel and would like to do the keel sanding, prep, and fairing myself, as it looks like there will be a lot of hours in that part of the work and I can hardly afford paying someone to do the bottom paint.
About 5 years ago, I had someone epoxy coat the keel (not sure what product). It looked great, but on the last 2 haulouts there was still plenty rust to be removed. I was able to get this industrial barrier coat called Amerlock which I used to patch the rusted areas after I'd sanded and prepped them last time.
This time around (hauling out Friday) I am expecting the keel will probably want to be sanded bare and re-coated completely since I just did patching last time. I don't think I can get ahold of any Amerlock this time (as it's only sold in 5-gallon drums), so I'm wondering what products and procedures should I follow before handing the work over to the yard to do the bottom paint.
From this forum and others, I heard good things about Interprotect 2000E as well as POR-15. Sounds like they're both good products and have a similar function - to provide a barrier from salt water reaching the iron.
After the initial scrubbing, sanding, and rust removal, it seems like I could go a couple different ways with the coatings. Which one is best for keeping the rust out and for adhering the bottom paint?
Maybe I'm confused but it seems like when folks use the POR-15 they are putting it directly on the metal, then fairing with epoxy, then painting. But when using Interprotect they fair first, then put on 10 mils worth of Interprotect coats, then paint. Is that right?
1) With POR-15
a) 2 coats of POR-15
b) several coats of West System epoxy filled with chopped glass for fairing
c) bottom paint (while the last coat of westsystem is still tacky ?)
2) With Interprotect
a) 2 or 3 fairing coats of west system epoxy + filler
b) 4 to 6 coats (!) of Interprotect 2000E
c) bottom paint while the last coat of interprotect is still tacky.
Isn't a primer needed between the west system and the bottom paint? What product would that be (I'm planning Interlux ablative bottom paint).
The Interprotect method seems more time consuming (all those coats of 2000E). It seems too like it will be difficult to hand off work to the yard folks for the bottom painting if I do either of these. Maybe I should let them put on the last coat of barrier coat whichever way I go, so that they can tie the
coats together properly.