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Thread: electrolytic pitting

  1. #11
    Join Date
    Feb 2014
    Location
    Boat at Lake of the Ozarks Missouri
    Posts
    643

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    Good suggestion from Moser:

    If you use Flux, be sure it is compatible with aluminum.

    Some are specific to copper, some are used with silver solder - ask your supplier first.

    Good luck on this project.
    Captain Tony
    2005 Summit by Triton - 220T Platinum 3Log
    2005 115HP Mercury Optimax - 228 Marine Master Trailer
    St. Louis & Lake of the Ozarks, MO.

  2. #12
    Join Date
    May 2013
    Location
    Edwardsville, IL
    Posts
    311

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    Today I went to the boat tried everything out. The pits were previously hit with a SS wire wheel. (I only did a few, trying to figure out the procedure) I used a dremel with the tiniest grinding burr (under 1/8") on the slowest speed to clean out the pits. This is like prepping cavities. On the entire 5th Army, by the looks of it. Then I heated the area with MAPP gas & brazed in the pits. I then took the dremel & put in a sanding drum, grinding down the excess solder/brazing material & went over that with a sanding block with 120 grit paper. I noticed a tiny spot which still had a bit of a pit, so I rebrazed the area again & repeated the grinding/sanding procedure. This was not a fast repair. (See photos. Hopefully I'll get them in order from wire brushed pits, first brazing, rebrazing, then ground & sanded. I left the area slightly proud rather than sanding more on the surrounding AL pontoon.)

    That was my first repair & while it will do, I knew I had to refine the process. There is a router attachment in my Dremel kit & an "end mill" type carbide burr so I set that up to cut flush. This greatly speeded up the grinding process & having it set exactly flush eliminated the the need to use a sanding block.

    I still had the problem of not filling in the pits enough because I was trying to use as little of the brazing rod as possible (hence the need to go over some spots again, using up more of the not inexpensive Mapp gas). I decided to not be so stingy with the brazing rod & pile it on thicker, making sure the spots got covered the first time. The brazing rods aren't cheap either I'd rather spend a bit more than have to rebraze some spots, burning up both my time & MAPP gas.

    The brazing rods have flux already on them & the labeling says there's no need to add flux. Considering the AL is shiny bare metal flux shouldn't be needed anyway. The brazing rods are made from AL & ZN which melts at 735 degrees & is harder than AL.

    I'm not sure how to upload photos. I have them stored in Google photos.

    In order they show the first pits I repaired, after wire wheel. The first repair. Sanded after first repair. Sanded after second brazing. These were taken a few inches away from the pontoon & the camera isn't the best. Then there's the Rt Rr of the boat, Lt side of boat fwd & aft, & a close up of another spot of pits.
    1994 Tracker Party Cruiser
    115 hp Merc, 2 stroke

  3. #13
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,232

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    Sounds like you are honing the process and have the right tools. Now you just have to "eat the elephant" as they say, one bite at a time.

    Photo posting is a PITA, if you can give us a link to the google pics, we can look and see if we have any tips.

    We used the aluminum zinc alloy in injection molding and called it Zamac, maybe see if you can buy Zamac bars or rods and dip in flux and braze old school for less $$$?
    2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
    1996 Mercury 50 ELPT4S
    1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  4. #14
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    94

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    If you think there’s a possibility that it’s the marina’s fault.... are you sure you want to keep attempting this repair? Entirely new tubes would be MY goal if it’s the marina that caused it.
    Have you checked with your insurance policy to see if it will cover this sort of damage?
    2015 SouthBay 522FCR w/150 Yamaha

  5. #15
    Join Date
    May 2013
    Location
    Edwardsville, IL
    Posts
    311

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    Here's where I have my photos: https://photos.google.com/album/AF1Q...11XyfGkghS77Qb

    I've got all the rods the job will take. I've been getting better at not using too much. I add the braze/solder, which will then sag a bit. Then I reheat it & spread it back up with a butter knife. If I find a pit needs to be refilled after grinding, I only need to heat the solder (not the whole area) up to temp to add a bit more. I've got about 40% done as of today.

    The fun part is gonna be finishing the 40% of the bottom of the logs. (I can only go down to about 4" above the bunks before I start burning the carpeting.) I'm use 4 screw jack piers such as those used in basements to level floor joists & raise one side at a time, just a few inches. Then I'll remove the bottom bunks (I've already removed the side bunks) & be working on my back, over head & to the side. I can attest that dripping braze material is a lot hotter than electrical solder & does not cool down nearly as fast.

    I'm not certain if the pitting was the marina's fault or my boat's. My sacrificial anode was long overdue to be changed. I used to have 2 on my lower unit, but 3-4 years ago I replaced the original unit (after I let it freeze solid in the winter) with a like new older unit which does not have anodes so my boat was relying on the transom anode. Which was that fuzzy white thing I was never sure was. I have a guy who's gonna test my slip for stray current before I put it back in. IF I can get it back in this year. (I'm running out of decent weather to work on the thing. Then today, the generator wouldn't start. Seems the Nylon Bendix gear stripped its teeth off. The boat is not near electricity so the generator is necessary. Onan doesn't sell starter Bendixes [SP? Bendi? Bendixia?] so I had to order the whole starter, but it should be in within a couple days. Arrgh)

    I don't want to try an insurance claim because I've already had 2 (hitting a stump on my 3rd (1/3) pontoon & for having my trailer stolen). They haven't raised my rates yet, but they're not making any money off of me.
    1994 Tracker Party Cruiser
    115 hp Merc, 2 stroke

  6. #16
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    94

    Default

    The most expensive insurance you will ever purchase is.... the loss you never submit for claim. THAT is a TOTAL waste of your money.

    And your tubes are the major/primary item of your boat.

    Just sayin’... (However it appears you have already made a decision on this one.). Good luck on this repair. I’ve never heard of anyone doing what you are doing.

    I hope the alloy you are applying will not react unfavorably with the base-alloy of the tubes over time and that it remains structurally sound.
    2015 SouthBay 522FCR w/150 Yamaha

  7. #17
    Join Date
    May 2013
    Location
    Edwardsville, IL
    Posts
    311

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    I have never heard of anyone doing what I'm doing. I also haven't heard of many others having the problem that I do. Hopefully, my repair will work. I don't trust epoxy to go through a hard freeze with my pontoons frozen in ice for 2-3 weeks. While I'm not certain this repair will survive such conditions, I have more confidence brazing in metal than I do glue.

    I'm not sure that my ins. will cover this problem since it's not an accident & a good argument could be made that it's my fault for not maintaining the boat by never replacing the anode which was 36 years old. Proper upkeep of a boat (or anything which is insured) is a pre-condition of having insurance.

    I made a mistake by not taking my boat out of the water for a year & 1/2, (as I figured I could get by with it [most larger boats don't come out of the water yearly] because I've never had this problem before) I won't make this mistake again. (Outboard engines don't need their water pump impellors replaced every 2 years, nor does a solid lower unit need its oil changed that often.)
    1994 Tracker Party Cruiser
    115 hp Merc, 2 stroke

  8. #18
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    94

    Default

    Normal “wear and tear” would not be covered by insurance.... but electrolysis caused by defective equipment or by the improper operation by others (the marina or a nearby boat in the water) which causes electrolytic damage to your boat... is not only likely covered by your policy...it is also subrogate-able to those who harmed your boat.
    I’d likely have investigated that possibility, but it IS your choice, and I hope this works out for you.
    2015 SouthBay 522FCR w/150 Yamaha

  9. #19
    Join Date
    May 2013
    Location
    Edwardsville, IL
    Posts
    311

    Default

    I'm not sure the problem isn't on my end. I'm certainly not going to accuse the marina of causing the problem unless I know for sure it was their fault & can prove it. They could easily decline to renew my lease next year & then I'd be screwed.

    I've got 1 pontoon completely repaired. I'm getting the process down & should have the other log & the short 3rd log done in 4 more working days. It takes about an hour per linear foot to complete a log (including jacking/piering boat, cleaning, routing pits, brazing, sanding to flush). This repair is a lot more labor than money. I'll get it done & it'll be in top shape for next year.
    1994 Tracker Party Cruiser
    115 hp Merc, 2 stroke

  10. #20
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,232

    Default

    I admire and respect what you are doing, but I just thought of something. Have you considered that you are repairing the pits with the most sacrificial material now on the boat? I would consider leaving it on a little on the thick side. Think of the small repairs as small diameter welding rods, they will burn up faster than the anode.I would check this very shortly after putting it back in the water, and based on what you see, maybe start shopping for tubes.
    2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
    1996 Mercury 50 ELPT4S
    1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

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