Stainless exhaust manifold repairs?

[Steel N Time]

Seeking a little guidance from those who may have experienced similar or made repairs.

We have twin 12V71TI’s in our boat. The wet exhaust manifold come down from each turbo, tying into a cross piece that is graduated larger as it approaches an elbow, where is has a 10” straight section.

That is the exhaust manifold it then is connected with a short section of exhaust hose to the fiberglass pipe and mufflers headed out the stern. I noticed some leakage at the straight section directly after the elbow, probably mild corrosion that began at the welds.

The boat is in Mexico and sourcing materials and quality tig welder can be questionable, so I am exploring repair options.

One option is to take a small tig machine and two pieces of stainless tubing 10” diameter 10” long, cut off the straight section and weld new on….

Another option I was considering, but not sure if it is acceptable practice, would be to sand down the stainless and glass it. Fiberglass materials are readily available down there. Is this an acceptable idea? Will fiberglass bond to a roughed up stainless? I would wrap the entire circumstance for strength.

I used a piece of exhaust hose and some spare clamps as a temporary repair, so it is not leaking, but that was a temp repair only.

Any thoughts or feedback would be great! Thanks!

 

[Arc]

Glass over SS will fail and you will have a mess. Wrapping and welding will be a better repair . Tig welding SS is simple with very little practice needed.

 

[Steel N Time]

Thanks! That is what I suspected. Wrapping will not be the preferred repair, we will cut off the 10” straight section and tig on a new straight section so the diameter fits nicely into the hose.

Tig welding is not a concern and we have a small portable tig machine. We will source gas locally.

I just had a moment where I thought…. Hmm…. “What about glass”…. Easier and could be done in place… Easy is often not best. Hahaha

 

[Bmarler]

i always prefer tig for this sort of thing, but you could stick weld it too. if finding argon down there is an issue i wouldn't hesitate to stick it.

 

[KnotYet]

My concern would be contaminating the weld with soot from the inside of the tubing. If that area is cleanable in place then you should be OK.
Obviously bring along some 316 rod if you plan to use any filler.

 

[Steel N Time]

i always prefer tig for this sort of thing, but you could stick weld it too. if finding argon down there is an issue i wouldn't hesitate to stick it.

Thanks! My friend has a small tig machine that will be easy to bring down, the argon is readily available, so it should be easy enough… probably take 2 days max to pull exhaust, cut, weld, and put it back.. two engines, so 2X….


If fiberglass was a viable option the exhaust would stay in places and it sets up pretty fast, so it would be done much quicker…. General consensus seams this is not a great idea… I am sourcing 10” stainless tube now…

 

[Steel N Time]

My concern would be contaminating the weld with soot from the inside of the tubing. If that area is cleanable in place then you should be OK.
Obviously bring along some 316 rod if you plan to use any filler.

The entire exhaust manifold will be removed, a 10” straight section cut off and then a completely new 10” straight section welded back. It will be properly prepped. We will definitely have filler with us..

 

[BeeJay]

316l

 

[Steel N Time]

316l

Thanks! That’s what I’ve been looking for…

 

[mvweebles]

Surprised you're having trouble finding a competent welder in Mexico. For the most part, metals come from the US and aew expensive, but decent welding skills seem pretty common.

Out of curiosity, what part of Mexico are you in?

Peter

 

[Steel N Time]

Surprised you're having trouble finding a competent welder in Mexico. For the most part, metals come from the US and aew expensive, but decent welding skills seem pretty common.

Out of curiosity, what part of Mexico are you in?

Peter

We are in Nuevo Vallarta and we had some other stainless work done and there seems to be a lack of quality tig welding ability.


Mig and arc and a grinder and polish it up is available. I had a small fabrication job a couple years ago took multiple tries and return trips. The quality just doesn’t seem to be there. Materials are definitely tough to find as well. I have searched out brass fittings at multiple places and they seem to like hypalon style parts a lot..


This being a wet application with potential for leaks if not done well, I am managing the repair and don’t have time for multiple trips back and forth.


Around the docks and at the local ship yard it seems each person wants to help out their friend and you get led down a path of dead ends over and over…


Getting a wood rail was ridiculously difficult! Multiple “carpenters”. I made a template and went place to place. After 5 days the first guy didn’t use the template I made and simply eliminated the arch and made it squared off… it didn’t fit at all of course, then he said he would re-do it, then he wouldn’t return the bosses number…. The carpenters work through the lumber supplier and make doors, furniture and things like that… Finally after three months Anne who runs the wood shop got a guy to do it… We accepted the product, but it was done horrible, wood glued on the bias to save materials and use a bunch of short pieces….


Another example: We installed a new generator, I took a hydraulic crimper, quality ends, quality cable and planned on making nice new cables. I turned my back for a few minutes and the “electrician” had taken my cable and crimps out to the docks and beat them flat with a hammer as a crimping method… :-(


Basically, my experience for the last few years has been similar in many repairs. They get it done with whatever they have!


So… My friend and I will make this stainless repair to ensure no sinking due to leaky exhaust and a repair that lasts..

 

[Snapdragon III]

I just did the exact same repair you are thinking about on my tiny generator exhaust. It worked great, but it was a much easier project on a 1" exhaust pipe, than a 10" pipe would be. It was a big relief to be able to fix it for the price of a 6" SS nipple, and not have to get a whole new exhaust fabricated.

 

[Arthurc]

Steel N Time,
Are you sure the current pipe is 316? I’d double check, if everything is 316 then 316L is the right filler, but lots of stainless pipe is not 316 and they make a special rod for joining dissimilar stainless and or carbon which is 309L, I’ve used 316L rod to join 304 to 316 a bunch and it works fine but watch out for cracking.
Also make sure you bring stuff to passivate the welds after or you will have issues in the future, a wire wheel at the minimum but if you can get your hands on a tigbrush they work brilliantly.

Best of luck on the repair!
AC

 

[Steve1.0]

Basically, my experience for the last few years has been similar in many repairs. They get it done with whatever they have!

I've had very similar experience in the Bahamas.