Questions after removing bottom paint from keel on 44DS 2007

R

ramoore

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Dec 1, 2020
39
Hunter 44 DS Deale, MD
Hi,

I just had the bottom of my (relatively new to me) 2007 44DS soda blasted for a full re-barrier coat & re-bottom paint.

The hull looks pretty good, but I have questions about the keel. My documentation says that it is made of lead (I believe the switch to iron was 2008). I thought that the lead keels were encapsulated in fiberglass, but I don't see that on mine.

So, question one is do I actually have cast iron? I'll stick a magnet on it tomorrow, but didn't have one with me today.

There does seem to be some kind of fairing material on it, but it flakes off pretty easily in some places. The first two pictures show the same spot before and after I flicked some off with a fingernail.

Assuming this keel is lead ... Do I need to just chip off the loose stuff and re-fair it, or sand it off completely and start over?

Any advice is welcome.

Thanks!
 

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jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
Please know I have no personal experience with soda blasting, but two things jump out at me:
  1. looks like lead;
  2. they did a rather incomplete job of blasting to leave so much of that white paint on the keel.
You wouldn't normally barrier coat the keel, I don't think. I think you would make sure it's well caulked to the hull, and then fair it if you're picky. I would barrier coat the fiberglass hull, of course.
 
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shemandr

shemandr

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Jan 1, 2006
7,600
Slickcraft 26 Sailfish
Agree with jviss. I think you need to sand the keel smooth. By the time you do that you'll be basically removing all that coating whatever it is. I would cover the lead keel with barrier boat or epoxy before the bottom paint. You don't need to protect the keel from water intrusion but I think there needs to be some sort of primer between the metal and bottom paint.
 
Davidasailor26

Davidasailor26

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May 17, 2004
5,689
Beneteau Oceanis 37 Havre de Grace
shemandr said:
You don't need to protect the keel from water intrusion but I think there needs to be some sort of primer between the metal and bottom paint.
Click to expand
:plus:

Looks like lead to me too. You’ll need to sand it well enough to be shiny before fairing or priming again, which probably means smoothing at least some of the existing fairing compound down. (Obviously use lots of PPE when sanding lead.) Once it’s shiny you can apply one coat of barrier coat as a primer. Fair as desired, apply another barrier/primer coat, and paint.
 
Joe

Joe

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Jun 1, 2004
8,199
Catalina 27 Mission Bay, San Diego
I'd be interested in the yard master's opinion, as well as your local chandlery.
 
jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
ramoore said:
It seems to be unanimous. And, everyone's advice here agrees with the instructions I found from the paint supplier, Pettit, that I found online this morning. https://pettitpaint.com/media/4445/pettit-paint-underwater-metal-systems.pdf

I'm not sure where I picked up the idea that the lead keel would be encapsulated in fiberglass.

Thanks everyone!
Click to expand
Are you going to go back to your soda blasting contractor and ask about what he left behind? Or maybe, I was thinking, that's just soda, and would come off with a pressure washer?
 
Hayden Watson

Hayden Watson

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Apr 5, 2009
3,131
Catalina '88 C30 tr/bs Oak Harbor, WA
One thing to keep in mind with any underwater metal prep. The surface oxide layer forms very quickly after you abrade the metal so you want to cover it as soon as you can. I had to refair the lead keel on my C30 last year because there were sections of the original fairing that were failing. When it came out of the water, there were large sections of barnicals while the majority of the keel and hull were clean. It also had what appeared to be blisters on the keel. All of these areas were places where the fairing had let go of the lead.
I used a sharp scraper and sharpened pointed trowel to find and remove any suspect fairing down to bare lead. I feather edged all of those spots and abraded the lead with 60-grit and a good vacuum system. As soon as I finished each area I would make a final pass with the sander and mix a small batch of neat epoxy to cover the lead. I used SystemThree because it is blush free and can be coated over up to 72-hours without sanding.
After all of the bare spots had been coated I used the SystemThree underwater epoxy fairing compound to fill and fair the low spots. I had never tried this before but really liked it. It is a 2:1 epoxy fairing compound which is easy to get the mix right. Just make 3 equal sized blobs and mix together. I was able to sand it by had with my long flex board and 40-grit paper.
After I was done fairing the surface, I coated over the keel completely with a coat of neat SystemThree epoxy and after it cured to tacky, I applied bottom paint.

This is how it looked after it came out of the water. You can see the patches of mussels on the trailing edge and the "blisters" that I had popped while they were raised up. Note: If you do not find and break the tops off of blisters right after the boat is pulled, they will shrink down flat and you will not be able to find them the next day.
20211006_120244.jpg

This is what the keel looked like after chipping off all of the loose areas. More was revealed during feather edging because I would chase any loose bits until I have fully adhered fairing against the lead. I did say good vacuum system. Note the tarp under the boat. This was taken after I had completely sanded the hull bottom paint and there is no dust on the tarp. I did have about 25 pounds of dust in my recovery system which added up to all of the previous bottom paint jog and about 1/2 of the one before that.
20211011_171100.jpg

This is what it looked like after fairing and top coating with neat epoxy to seal everything.
20211018_103116.jpg

I forgot to take a picture of the completed job before launching but his is one of the other side on the way to the ramp.
20211026_093737.jpg
 
R

ramoore

.
Dec 1, 2020
39
Hunter 44 DS Deale, MD
Hi everyone, just wanted to give an update. The keel is indeed lead, not iron. Thankfully.

Most of the old fairing is still well adhered, but there were some spots where I could hear that it had separated when I tapped it. So, I chipped away all of the loose bits. Today, I did the sanding needed to bring it back to bright metal using a stiff wire brush. Working in sections, my wife followed behind me with the thinned Pettit Protect epoxy as a primer. So, there was little time for a new oxide layer to form. Hopefully we did this right, because I really don't want to do it again.:what:

Once that coat had dried sufficiently, I re-faired the bad spots. It's not perfect, but way better than before.

We also finished the first barrier coat on the whole bottom.

Tomorrow, I'll sand the new fairing, re-clean the area with solvent.

Then, I'll do another barrier coat, and finally my bottom paint.

Scheduled to go back in the water at 8:30am on Wednesday. I hate working with a short deadline. This was not the original plan.
 
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jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
May I please ask, if you don't mind, the cost of the soda blasting job?
 
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