front of pontoons look etched

vintage_car · May 14, 2012

On a newly purchased (used pontoon) boat, I noticed the front of the pontoons seem to be etched, and sort of eaten away below where the waterline stain is on the pontoons. It is only around the weld seams at the front of the pontoons. what would cause this? Is there an epoxy or some sort of seam sealer that I can put on it, to make sure there are no pin holes in the pontoons?

MH Hawker · May 14, 2012

Re: front of pontoons look etched

How about some pictures.

5150abf · May 15, 2012

Re: front of pontoons look etched

that is odd that it is only in one spot, if it were electrolosis it would be all over the tube you would think, as Hawker sadi, if you cna get up a pic of it maybe we can help but I am not sure what you are talking about and it is certialynothing I have heard of before.

Normally when that happens it is the entire tube below the water line, does it have tiny white pillars on it, that would be electrolosis.

vintage_car · May 15, 2012

Re: front of pontoons look etched

I'm betting electrolysis from your description. I will get pics this afternoon though. So how do I patch it and prevent further corrosion if that is what it most likely is?

5150abf · May 15, 2012

Re: front of pontoons look etched

Get anodes on all the parts that are in the water, all tubes and the motor pan, the anode will corrode before the tube will.

I still say if it was electrolisis it would be over the entire tube not one small area.

Do you know if any part of the electrical system is grounded to the boat itself, that will really accelerate it if it is.

vintage_car · May 15, 2012

Re: front of pontoons look etched

here are a couple pics. any welds below the water line has this sort of pitting/etched look.

halfmoa · May 15, 2012

Re: front of pontoons look etched

Looks like poor welding prep and or foreign material in welds but that's just my opinoin...

81 Checkmate · May 15, 2012

Re: front of pontoons look etched

Wow that doesn't look good... I take it you didn't see that when you bought the boat!

Looks like the welds are getting ate up below the water line and the heat affected zone on the base metal is being affected. Coulda been bad filler metal when it was welded or lack of sheilding gas when welding. Notice above the water line the welds look OK!

I am sure 5150 will chime in.... he is the pontoon expert and should have a solution for you.

Good Luck!

MH Hawker · May 15, 2012

Re: front of pontoons look etched

I would say electrolosis. but 5150 is the man when it comes to logs.

5150abf · May 16, 2012

Re: front of pontoons look etched

I have never seen localized elctrolisis, all the ones I have seen it is everywhere.

That looks lke purosity in the weld and alot of it, that is from welding with little gas, way too much gas or a contamanant in the weld, it is little bubbles that get into the weld, could also be from using the wrong filler rod but that is just a geuss, very very odd.

I am really at a loss since I have never seen anything like other than pourosity.

If it were mine I would grind out the bad weld and redo it.

81 Checkmate · May 16, 2012

Re: front of pontoons look etched

Just my opinon - But i think if someone were to try and reweld those seams they would make a mess of it......... Unless they really know what they are doing with welding corroded aluminum. They will need to know how or have done repairs like this.... It just doesn't take ( Weld ) like new alum does. Just my opinion tho........

5150 - Do you think that some kind of epoxy filler or marine tex would work? Say if you cleaned up the welds with a flap wheel on a grinder, but not grind the weld out completly. Just enough to get the porosity out of the weld, then fill with ??????????????

vintage_car · May 16, 2012

Re: front of pontoons look etched

so electrolosis would be everywhere, not just on all welds below the waterline? Its odd to me that a factory welded pontoon would have that sort of debris/low gas issues at the factory? Not debating, just seems odd. So as 81checkmate stated...is there an epoxy bottom coat to seal/clean up the mess? Should I get anodes? I don't see any, and what type/where do I get and place anodes?
All welds below the water line look like this.

5150abf · May 17, 2012

Re: front of pontoons look etched

I am at a loss, I have never seen this before but as I said it looks like pourosity, not knowing how it was welded, mig or tig, it is hard to say how it got in there, with a mig if the cup is dirty it will geive you pourosity and with a tig the gas line could have had a leak but I still don't think it is electrolisis.

If it came into my shop I would grind out the old weld and replace it with weld, there is no epoxy or anything like that that will take the place of a weld.

Find a local welder and have him look at it and see what he can do for you.

vintage_car · May 17, 2012

Re: front of pontoons look etched

Im looking more for something to prevent the welds from leaking. Having entire pontoons grinded out and rewelded sounds pretty expensive. If you did the work what sort of shop estimate would I be looking at, trying to compare it to maybe an epoxy/bottom paint to prevent further damage to the welds?

81 Checkmate · May 17, 2012

Re: front of pontoons look etched

you are probley looking at $35 to $75 per hr to repair the welds. It all depends on if its a rep shop or a backyard guy. Now this is just a guesstamet.

Do you leave it in the water at a slip? Or do you trailer it?

Are there any drains in the pontoons? To check and see if you are takeing on any water.

If you trailer it you could posibly experiment with different epoxys and keep a good EYE on it to see what happens.

Thats a real bummer!

vintage_car · May 17, 2012

Re: front of pontoons look etched

It hasn't been in the water yet. the transom has to be fixed and the lower unit repaired. I was going to put it in a slip, but the problems continue to add up and I have yet to have a chance to enjoy it. seems like I turn around and there is another LARGE expense. BOAT (Bust Out Another Thousand).

Is there a link or site that has the process of how to apply the epoxy coatings and where to buy them?

I would also need to find out how to get the pontoon in the air so it is prepped everywhere.

there are drains in the back of the pontoons- the pontoons are foam filled, someone said there were hatches you can open on the topside of the pontoon and you could put water in them and see where it leaks from...is that okay to do?

81 Checkmate · May 17, 2012

Re: front of pontoons look etched

1. - Is there a link or site that has the process of how to apply the epoxy coatings and where to buy them?
Answer - Goggle is your friend on this one....You will have to do alot of asking questions if epoxy will work in your situation!

2. - I would also need to find out how to get the pontoon in the air so it is prepped everywhere.
Amswer - You will have to be creative on this...... you will have to a section at a time. Depending on your trailer type.. could maybe remove the outside bunk only to repair, then install back on then remove inside bunk and so on. Just a thought on this one. Post some pics of your set up and im am sure someone will come up with an idea.

3. - there are drains in the back of the pontoons- the pontoons are foam filled, someone said there were hatches you can open on the topside of the pontoon and you could put water in them and see where it leaks from...is that okay to do?
Answer - I am by no means an expert on this, But 5150 should have an answer.
My thinking is........
1. Someone foam filled the pontoons becouse they were leaking.

2. If you can get to the hatches - Have a look see and verify the foam

3. Pull the drains now and see if water comes out. With it not being in the water for awhile it should be dry. If it drains water then its taking on water and the foam is water soaked. Not good!

4. To check for leaks......No WATER - if they are foam filled...... do not put water in them... it will never dry out.....

5. If they are foam filled..... Chances are that no one will weld repair your toons with the foam in - em, I wouldn't

Hope this helps.... By the way in your case... BOAT does = Bust out another thousand!

vintage_car · May 17, 2012

Re: front of pontoons look etched

I found this site...contacted the admin to get more product info, but it looks like it might be a decent fix for my problem
http://www.theboatshopmotorparts.com/alumrepairinstruc

5150abf · May 18, 2012

Re: front of pontoons look etched

I built U tubes years ago that were foam filled btu have never heard of anyone foaming a round tube unless it was the previous owner and I have certainly never heard of hatches in the toons, unless you have access from the deck you would have to remove the tubes to get to the hatches.

Have you removed the plugs to see if there is any water in the tubes?

My concern with grinding out the welds and using epoxy is that it won't be stng enough, if this makes sense, a weld is mechanical bond and is very very strong, epoxy is a physical bond that just sits on top but really has no strength, if you grind out the strong bond and replace it witrh a weaker one I woudl worry baout eventually cracking the weld and taking on serious water.

If you absolutely don't watn to take this to a welder then only remove what weld you have to and use the stuff in your link.

Keep inmind I am at the manufacuring level and the fixxes I do have to be retail sellable so I don't ever cobble anything like this, as long as you don't take out too much weld and the foam isn't water logged you should be okay.

81 Checkmate · May 18, 2012

Re: front of pontoons look etched

Great advise 5150 - Dont want to loose the integerty in the weld!

looks like the product you found could be the stuff you need. Instead of grinding the affected welds smooth, try using a wire wheel on a 41/2" angle grinder to clean the welds up. Harbor Freight in your friend!

Do not get a carbon steel wheel! They make them in Stainless! Also do not get the cup type, get the disk looking type. As it will clean the metal better. Turn the grinder sideways and use the wheel on its end, instead of using it flat. Be sure to use the handle also....... Also please keep the guard on the grinder... this will help you out in the event of a kick back.

Use extream caution when using a wire wheel........ They can get cought up in loose clothing...... And by all means wear EYE and Hand Protection...... those little wires go everywear......!

Hope this will work out for you. Good luck and let us know how it turns out!

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