Klamath 19 Corrosion
Posted: Fri Nov 18, 2022 3:04 pm
Hello to all. First, let me contribute a profound thanks to those who have offered their time, ideas and experience on this site. I’ve been reading last few weeks since I’ve purchased my first alum boat. Previously I owner ad 24’ glass boat and after selling always wanted an aluminum.
So, the “new” boat. It’s a 2004 Klamath. Purchased and didn’t know much about alum corrosion beforehand. Used primarily in salt. Original owner was neighbor of family member and I heard he took good care of the boat through the years, and that it sat (mostly) covered last 8-10 years.
Found no obvious holes in bottom, did a couple test rides with no obvious water intrusion after pulling plug, hull looked pretty darn sound…then I took off the deck a week after. Discovered decent amount of organic material, somewhat dirty styrofoam, and some corrosion. Worst if the corrosion is in the bilge, within a few feet of the drain plug. Poultice corrosion it would seem.
I’ve since removed all foam, washed clean and rinsed heavily, Green 3M, then sanding with 120 and 400. I can’t find any holes, but there do seem to be a few tiny corrosion pits, like around 1/16th -1/8th diameter and same depth perhaps, that are in some flowering spots before I removed the flowering.
So no obvious holes, but some localized very small Swiss cheese near drain plug on bottom. Here and there on rest of the bilge has a few spots of flowering that seem to have some less obvious pits.
My current fix is to continue with etching with either alumibrite or shark hide, then boshield the complete bilge, then pray.
My buddy does own a welding shop and I will have him fix a few deck braces that have small cracks where center console attached. From what I have read in this forum, welding may not be needed. But if it is, I’d have to drill out all pits, and make sure my welder had experience with the thin material. Then pray. Or, perhaps a patch, which seems difficult considering the bends in the hull from the bottom chines.
AAaaaamd now my question please: Should I just boeshield after etching, and monitor? Or should I try other material filler first from the top/inside of bilge to fill the pits, then paint? Or fill with 5200 and paint? Or just paint? What about braising with flux and “pooling” over the areas?
I keep going back and forth on what my situation might call for, it doesn’t look like it’s comprised the hull too much yet, doesn’t leak from what I can tell, but I’d like to take some action.
Any thoughts or guidance appreciated!
Thanks,
Jed
So, the “new” boat. It’s a 2004 Klamath. Purchased and didn’t know much about alum corrosion beforehand. Used primarily in salt. Original owner was neighbor of family member and I heard he took good care of the boat through the years, and that it sat (mostly) covered last 8-10 years.
Found no obvious holes in bottom, did a couple test rides with no obvious water intrusion after pulling plug, hull looked pretty darn sound…then I took off the deck a week after. Discovered decent amount of organic material, somewhat dirty styrofoam, and some corrosion. Worst if the corrosion is in the bilge, within a few feet of the drain plug. Poultice corrosion it would seem.
I’ve since removed all foam, washed clean and rinsed heavily, Green 3M, then sanding with 120 and 400. I can’t find any holes, but there do seem to be a few tiny corrosion pits, like around 1/16th -1/8th diameter and same depth perhaps, that are in some flowering spots before I removed the flowering.
So no obvious holes, but some localized very small Swiss cheese near drain plug on bottom. Here and there on rest of the bilge has a few spots of flowering that seem to have some less obvious pits.
My current fix is to continue with etching with either alumibrite or shark hide, then boshield the complete bilge, then pray.
My buddy does own a welding shop and I will have him fix a few deck braces that have small cracks where center console attached. From what I have read in this forum, welding may not be needed. But if it is, I’d have to drill out all pits, and make sure my welder had experience with the thin material. Then pray. Or, perhaps a patch, which seems difficult considering the bends in the hull from the bottom chines.
AAaaaamd now my question please: Should I just boeshield after etching, and monitor? Or should I try other material filler first from the top/inside of bilge to fill the pits, then paint? Or fill with 5200 and paint? Or just paint? What about braising with flux and “pooling” over the areas?
I keep going back and forth on what my situation might call for, it doesn’t look like it’s comprised the hull too much yet, doesn’t leak from what I can tell, but I’d like to take some action.
Any thoughts or guidance appreciated!
Thanks,
Jed