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Post by james211 on Apr 17, 2024 6:35:06 GMT -5
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Post by fishnfool on Apr 17, 2024 9:46:36 GMT -5
Yikes. What model and year boat is this?
Looking at those pictures makes me think it's galvanic corrosion caused by the bottom paint. In other words the SS fitting were not primed before application. My thru hull fittings are not painted and my boat sits in the water and the fittings look practically brand new 14 yrs later.
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Post by james211 on Apr 17, 2024 9:55:19 GMT -5
Interesting, it’s a 2016 276 DC. This is my second season with the boat, so I can’t be sure what was done prior other than there is paint on the through hulls.
Any suggestions?
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Post by fishnfool on Apr 17, 2024 10:09:13 GMT -5
I like metal for through hull fitting so I'd still replace with ss fittings but make sure they are primed before applying bottom paint.
I seem to recall someone replacing supper through hulls on here a couple few years ago but can't remember who.
As a rule of thumb I don't paint any of my metal through hulls including the bronze through hulls. My suppers do not sit underwater at the dock so it's not an issue for them
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Post by lainiej on Apr 17, 2024 10:11:21 GMT -5
I would try and clean them up and see what you have. Mine are original 2007 and boat is kept in the water and still look fairly new.
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jerryk
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Post by jerryk on Apr 17, 2024 10:40:26 GMT -5
I agree with Chris, this looks like galvanic corrosion. A good example of why you don't paint metal fittings with copper based bottom paint. Clean 'em up as best you can and see what it looks like next year without any bottom paint on them once they are brought back to metal only (no paint). Best case they look good yet and worst case you can still replace them next year.
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Post by james211 on Apr 17, 2024 11:41:15 GMT -5
So I scraped as much paint off as I could, used some barkeepers friend, and they cleaned right up. Going to bring the dremel down and clean them up a bit more. I think I’m set! We’lll see how they look at end of year.
Thank you!!
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Post by reelkul on Apr 18, 2024 10:20:42 GMT -5
Its not galvanic corrosion, its crevice corrosion. Remove the bottom paint, and keep the stainless parts exposed. Make sure that they are bonded properly. If they are pitted, you may need to replace them. Any pitting will create crevices for salt water to reside, and you have a continuation of the crevice corrosion.
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Post by finatic on Apr 18, 2024 17:48:51 GMT -5
Its not galvanic corrosion, its crevice corrosion. Remove the bottom paint, and keep the stainless parts exposed. Make sure that they are bonded properly. If they are pitted, you may need to replace them. Any pitting will create crevices for salt water to reside, and you have a continuation of the crevice corrosion. Interesting, would something like JB weld be a good idea to fill any small holes.
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Post by reelkul on Apr 19, 2024 7:56:07 GMT -5
Its not galvanic corrosion, its crevice corrosion. Remove the bottom paint, and keep the stainless parts exposed. Make sure that they are bonded properly. If they are pitted, you may need to replace them. Any pitting will create crevices for salt water to reside, and you have a continuation of the crevice corrosion. Interesting, would something like JB weld be a good idea to fill any small holes. I have not tried it. But if I had pitting, I would just replace the through hull.
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Post by james211 on Apr 19, 2024 10:20:59 GMT -5
I’m going to clean them up a bit more, polish them and apply some collinite and see how they look at end of year. There was no noticeable pitting, although I’m sure it could happen at a microscopic level. Are through hulls sealed with 5200 or something easier to remove?
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jerryk
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Post by jerryk on Apr 19, 2024 11:15:17 GMT -5
They should be set with 4000 not 5200. Key words are SHOULD BE. I would clean and check on them again next year before deciding to replace. Also, you may not want to put wax on them (I was wrong! Editing now to say wax is ok since it apparently still allows the metal to get the oxygen to it that ultimately make it self-protecting with the layer of chromiun oxide that forms with oxygen exposure). Believe it or not, stainless exposed to air forms it's own layer of protection while it corrodes when left without oxygen.
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Post by james211 on Apr 19, 2024 15:11:17 GMT -5
So they should come out with a bit of elbow grease once the lock nut is removed?
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jerryk
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When not online I'm likely on Knot Online
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Post by jerryk on Apr 19, 2024 16:17:41 GMT -5
Yes (he says as his fingers are crossed for good luck...).
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Post by james211 on Apr 22, 2024 17:59:30 GMT -5
Had a maintenance guy lay boat yard look at through hulls, he’s pretty sure it’s galvanic corrosion but he said one season should let me know. Fingers crossed!
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