|
Post by james211 on Apr 22, 2024 18:13:50 GMT -5
Cleaning up and replacing a few latches, but a few that look great on the outside are bleeding from the inside. None of the latches have any bedding, probably for easy replacement. If I was to use some bedding what would you recommend?
|
|
jerryk
Captain
When not online I'm likely on Knot Online
Posts: 599
|
Post by jerryk on Apr 22, 2024 18:31:59 GMT -5
www.unifiedalloys.com/blog/stainless-corrosionAbove is a quick read that explains a lot about stainless steel corrosion. Inside corrosion is likely caused by a lack of oxygen around the stainless steel, meaning it can't form it's protective layer of chromium oxide. So be careful about use of bedding that seals it off and I would say only do that where water intrusion is a concern, you may be doing more long term harm to it...but then again, if the original latches are now needing replacement and were probably bedded with 3M 4000 sealant or something similar years ago, maybe you are at the end of life for the metals in that kind of application. And you may buy some time by sealing them up just to keep water from getting in, at least until the metal gives out. Where you do want to seal it, use 3M 4000 not 5200 or you risk damage to the surrounding area once it needs to be removed.
|
|
|
Post by james211 on Apr 22, 2024 18:38:03 GMT -5
I appreciate the advice. The originals were not bedded, but they seem to be in an area that does get wet and clearly due to the design of the doors they’re not getting enough oxygen.
Last year I removed all of them, cleaned them up real good and used collite on them, which seemed to help most of them but a few have started bleeding again.
Also, it may have been due to my old canvas, which is now new so maybe I won’t have any more issues.
I’m just sick of the stains!
|
|
|
Post by hookedup on Apr 23, 2024 7:47:37 GMT -5
With all of my boats after a few years some of the stainless will bleed and some of the powder coating on metal will chip off. If someone has a way to avoid these, let me know. My Albemarle, Robalo and now Sailfish have all had the problems and it seems to start in the third year. I've tried a variety of things, but it happens regardless and as Jerry said sealing stainless only worsens things.
|
|
jerryk
Captain
When not online I'm likely on Knot Online
Posts: 599
|
Post by jerryk on Apr 23, 2024 8:30:09 GMT -5
Richard,
My boat surveyor told me about a product called TEFGEL which is used to provide some isolation between stainless steel screws and the powder coat tubes for the hard top. On my boat it obviously wasn't used at the factory because as you said around year 3 some of the powder coating starts to bubble off, due to the galvanic corrosion issue. Since I bought my boat at 4 years old, the damage had already started but I did get some TEFGEL and put it on the screws which was a bit of a pain since some were very tight. Truthfully, at this point I'm not sure it did provide any added protection as some of the bubbling seems to have progressed...so I'm not sure this is a recommendation for TEFGEL...then again, had it been used from the start maybe I wouldn't have the issue so anyone with a new boat may want to try it and see if it helps prevent the issue.
|
|
|
Post by hookedup on Apr 23, 2024 11:09:13 GMT -5
Richard, My boat surveyor told me about a product called TEFGEL which is used to provide some isolation between stainless steel screws and the powder coat tubes for the hard top. On my boat it obviously wasn't used at the factory because as you said around year 3 some of the powder coating starts to bubble off, due to the galvanic corrosion issue. Since I bought my boat at 4 years old, the damage had already started but I did get some TEFGEL and put it on the screws which was a bit of a pain since some were very tight. Truthfully, at this point I'm not sure it did provide any added protection as some of the bubbling seems to have progressed...so I'm not sure this is a recommendation for TEFGEL...then again, had it been used from the start maybe I wouldn't have the issue so anyone with a new boat may want to try it and see if it helps prevent the issue. I'm not sure it's due to the screws. Looks like corrosion on the hardtop base is causing the problem. On the Albemarle it was aluminum corrosion on the windshield frame. On the Robalo it was corrosion on the ski bar supports. My guess is it only takes a minimum amount of corrosion to lift the powder coat off the metal and once it cracks or flakes and the problem compounds. Once started there is not much you can do beyond cleaning up the metal and applying Orbit pure white.
I would have bought the boat without powder coating if they'd offered it that way. The white looks great in the beginning, but over time the paint always seems to crack and flake. It may be the screws starting the problem, but I guess it would need to have been treated during the build, not after.
|
|
jerryk
Captain
When not online I'm likely on Knot Online
Posts: 599
|
Post by jerryk on Apr 23, 2024 11:19:18 GMT -5
Yup, same issue I have. Right at the base where the top is screwed down into the hull, some bubbling has occurred and then the powedercoat flakes off. Started by dissimilar metals touching--stainless steel screws into the aluminum (I think) baseplate. What the surveyor said makes sense to me after seeing where the problem started, because there are no other areas that are bubbling off like that anywhere else on the top frame.
|
|
|
Post by james211 on Apr 24, 2024 6:03:36 GMT -5
Well the powder coat is a whole other issue, I gave up on that for now.
Regarding the bleeding, I guess I’ll just have to keep cleaning year after year, or buy ugly powder coated latches.
|
|
|
Post by fishnfool on Apr 24, 2024 6:53:24 GMT -5
Did you remove the screws and set them in caulk on reinstall? Proper bedding usually solves the problem.
Alternatively you could try sourcing some new high quality marine SS screws?
An issue I've seen with powder coating is, sometimes manufacturers start screwing into say the ttop frame after powder coating to install snaps or mounting screws etc. They often don't seal the powder coating after. So despite using nylon washers between the screws unfortunately salt water eventually works it's way in and starts attacking the exposed metal and the corrosion starts to creep under the powder coat leading to bubbles and eventually flaking.
|
|