Frustrating pontoon repair

[kevinwak]

I had a small crack in a pontoon on my boat. About 1-2” long on a vertical seam. In the past I have had horizontal cracks repaired and had no issues.
Well I took it to a friend who owns a pro welding shop and they said “no problem, we do stuff like this all the time”. Half a day later they say they are finished. I pick the boat up and their is a big ugly patch with welds that look like chicken poop all over it. Oh well, as long as it holds right? Wrong. I take it home and put 1-2 pounds of air in it and hear the leak right away. I take it back and they say sorry, we will get a tig in and fix it right. Didn’t I want it fixed right the first time? Now I am noticing an adjacent repair job done nine years ago is also leaking, even though it was good when I took it in.

Five days later they call saying the boat is done and it went really well. I go to pick it up, and it looks horrible, but am thinking as long as it holds who cares how it looks. Get home, park it in the drive and continue on my day. Next morning is hot and sunny after a day of rain. I am walking passed the boat and can hear air leaking. I crawl under and see bubbling from a weld on the opposite side of the pontoon from West they worked. One that has never leaked before. I call My friend and get excuses and he keeps telling me that the guys that worked on it are very experienced and there are no better in the area.

So I am finally smart enough to not take it back there, but am left with an embarrassment of a weld job that caused bigger leaks then what I took it in for.
Long story short. How do I choose a welder to do this repair.
Called a local boat dealer and they said they take all their repairs to this one local shop. Called them And chatted and they said they mostly use mig
Next called a local marine repair shop. They said they just bought a tig setup for aluminum and have a welder that they bring in to make repairs using their tig setup.
I am debating between these two or finding something in the city 3 hours away.

 

[kthompson]

I know aluminum welding is tough, thinner metal is tougher of any kind metal than thicker is. Agree the welds are rough looking but the best it looks in your picture it looks like the metal might be wrinkled a good bit. If so then that might be making varying distance in the gap being welded. Is it possible what ever caused the leaks you knew you had also caused some you did not detect or weaken the metal or seams which are failing as they are subject to new pressure test?

If my memory is correct I looked at a pontoon boat couple of years back and that company had theirs filled with foam. Found that interesting.

 

[PILOON]

Having done a lot of aircraft repairs I would be tempted to go the rivet patch route,

Shucks with countersunk rivets you would have to search to locate the patch but standard brasier heads would be even better.

We patched aircraft floats all the time and they never leaked either.

On the other hand the boating trade rarely crosses over to aviation so suitable trade personnel is not readily accessible.

 

[kevinwak]

I know aluminum welding is tough, thinner metal is tougher of any kind metal than thicker is. Agree the welds are rough looking but the best it looks in your picture it looks like the metal might be wrinkled a good bit. If so then that might be making varying distance in the gap being welded. Is it possible what ever caused the leaks you knew you had also caused some you did not detect or weaken the metal or seams which are failing as they are subject to new pressure test?

If my memory is correct I looked at a pontoon boat couple of years back and that company had theirs filled with foam. Found that interesting.

It was smooth. They added a patch when they blew through the tube. The adjacent welds didn’t leak before hand when I tested. I suspect they weakened as they are on the edge of the HAZ

 

[mercdv]

I'd maybe go with the shop that mainly uses mig if people recommend it. A proper mig weld on aluminum will hold up just fine. I'd be wary of a shop that "just bought a tig setup for aluminum and have a welder that they bring in to make repairs using their tig setup." That to me implies that they are new to the whole process and who knows about the welder's skill that they bring in to do the job. If you can, see if the dealer that recommended the mig shop has something that was recently repaired that you can inspect or see if the mig shop will let you come see a repair they are doing. That would be my first step.

 

[dragoneggs]

Having done a lot of aircraft repairs I would be tempted to go the rivet patch route,

Shucks with countersunk rivets you would have to search to locate the patch but standard brasier heads would be even better.

We patched aircraft floats all the time and they never leaked either.

On the other hand the boating trade rarely crosses over to aviation so suitable trade personnel is not readily accessible.

Yeah rivets and some polysulfide sealant will be much cleaner and do the job just fine.

 

[kevinwak]

I'd maybe go with the shop that mainly uses mig if people recommend it. A proper mig weld on aluminum will hold up just fine. I'd be wary of a shop that "just bought a tig setup for aluminum and have a welder that they bring in to make repairs using their tig setup." That to me implies that they are new to the whole process and who knows about the welder's skill that they bring in to do the job. If you can, see if the dealer that recommended the mig shop has something that was recently repaired that you can inspect or see if the mig shop will let you come see a repair they are doing. That would be my first step.

That is a great idea, checking past clients and actually looking g at the work.

Shops around here are primarily oilfield fabrication and the boats are more of a side job. The marine repair biz that bought the tig actually sounded knowledgeable in the process, I should also ask him for past references for the guy he uses to weld.

 

[RNeumann]

I’d call around for a shop that does tig and has some clue about AC balance. This shouldn’t be that hard.

Note in the video at about 2:45 in he discusses a very similar issue-

Aluminum Tig Welding: Setting AC Balance - YouTube

 

[kevinwak]

I’d call around for a shop that does tig and has some clue about AC balance. This shouldn’t be that hard.

Note in the video at about 2:45 in he discusses a very similar issue-

Aluminum Tig Welding: Setting AC Balance - YouTube

That was a really cool video. I learned a bit from it.

 

[yomax4]

Should have been an easy fix with the proper parameters. Funny they didn't leak test it after they welded it.