Exhaust Pipe Rust Through - Need a Source

[Four Suns]

I could use some help here.... As usual, right before a big trip, something pops up that needs to be fixed. First a cracked coolant tank bracket and now... rust through on the exhaust pipes.

The mechanic today had to take off the metal exhaust pipes to get behind the engines and get the cast coolant reservoir off so he could get this 49 cent bracket off. The new brackets the machine shop fabricated (see my other post) look great. What he found on the exhaust pipes, however, was rust through. These are straight stainless pipes that are 28" long and 8" in diameter and connect a blue silicone elblow from the engine (where the raw water is dumped into the exhaust) to an 8" black hose/pipe that connects to the water lift mufflers. It appears part of this stainless pipe sits in the water all the time and has rusted through. These holes were under the black exhaust hose connected to the water lift muffler so the only reason this was caught was because they were removed and inspected.

This is a simple part... straight stainless exhaust pipe that is 28" long and 8" in diameter... I need it by Tuesday... We are leaving for our month on the bay on Thursday and I want to sea trial everything before we take off... Anyone have any secret sources?

Also, I'll look at this later on "why" it happened but right now I need to just get these pipes replaced or I'm in deep doo doo with the family.

 

[Turtlesboat]

what if you just had someone weld a patch over the holes until you can find a replacement?

 

[Four Suns]

We discussed that today and I might have to do that... boy... that'll will look like crap though.

This pipe should be connected to the boat's bonding system... welding a screw terminal on the outside and connecting a green wire to it needs to be done as well.

The original pipe was made by DeAngelo Marine Exhaust out of Ft. Lauderdale and it has a part number stamped on it. I called them today at 4:00 and the receptionist put me in someone's voicemail and they didn't call back.

 

[Turtlesboat]

I think only you would know it was there. Send them up here, there are guys that fixed my exhaust on my jeep for $25 after I ripped a hole on a rock off roading. little patch welded on and bada bing, back on the road. probably last a couple of seasons until you can hunt down replacements.

 

[fwebster]

Gary,

Find someone locally who can TIG weld (heliarc).......a guy who builds towers, repairs aluminum tanks or boats, etc.. I know this isn't aluminum, but the heliarc process is the essentially the same and its the TIG welding machine we need. I really don't see anything there that makes me think a good welder cannot get you by until you can research the problem and get a better solution.

These tubes are also probably in stock at DeAngelo if you can get to someone who can approach this with a sense of urgency.

If we knew where Mr. Murphy('s Law) lived we could put a contract out on him.......... I'd hold him if you would shoot the gun!

 

[comsnark]

If it makes you feel better. . . .I had bought a jetski with a bulged rubber exhaust pipe. It was reinforced with duct tape. :smt119

After 5 years . . .I finally replaced the exhaust pipe this spring; even though the tape was holding up just fine. :grin: (this ski sees light use -> it is my backup machine only used when I have lots of guests).

I would call the welder. . . .and acquire proper parts for a more leisurely repair later.

 

[Four Suns]

You're right guys... I just need to get a patch welded in and research the problem and fix it right. This just caught me off guard today as I think those pipes should last a looooong time.

 

[Turtlesboat]

oh by the way, I was joking about sending them up here. :lol:

Shipping would cost too much, plus this weekend is my big night cruise.

 

[Four Suns]

I didn't sleep at all last night thinking about these stupid pipes... Now here's how you know you have a boating addiction problem when you "feel guilty" and wonder all night "what could I have done different" and "how could this happen to my baby"... etc...

It's interesting to note that some things on the engine are connected to the bonding system via green wires or they have zincs directly in them. Each engine has 7 zincs along with various green wire connections to the bonding system. This tube has nothing and is isolated with exposure to saltwater with the bottom few inches sitting in saltwater all the time. Could this be the issue? Should there be a green wire connection here or maybe even a zinc?

Add this little item to the list of things to look for when doing a survey on a 480 DB with Cummins QSM-11's.

On the good news side, the Rydlime flush I did seemed to work. With the cooling system all taken apart, the heat exchangers (aftercooler, oil, coolant, fuel) were like new. Granted I didn't get to peek on the coolant side of the coolant heat exchanger, but we are going to do a flush with Restore when the thing goes back together...

tick tick tick... gotta leave on the boat Thursday or I'm a dead man.

I'm going to go out and do a flush on my AC system heat exchangers today with some Rydlime.. I hope I don't find anything broken there as my wife likes to set the AC on 60 degrees... Ms. Ice Queen.

 

[fwebster]

I think your bonding issue is either an over sight or just cutting the cost of materials to closely either by Cummins or by Sea Ray.

Our boat is an older than yours and we do have 2 -6" DeAngelo welded stainless elbows isolated by rubber hoses in the exhaust plumbing on both engines and all have bonding wires on them. Would they have helped?.....perhaps. Should you incorporate bonding into the eventual replacement?....certainly.

If you have to get new ones made, the bonding lug should be a $3 add on. However, if you find a good welder and there is enough wall thickness left around the corroded area, the patched ones will be as good as new ones.

Stainless steel is just that. It is not impervious to rust and corrosion, but it takes a long time for it to show corrosion. Given enough time ...like imersed in salt water for 6 years and you will get some rust and pitting.

 

[Asureyez]

DeJa Vue!

FourSuns

WOW I went through the same issue a week before I'd planned to hed off to the Abacos. DeAngelo wanted a freaking fortune for a new stainless elbow and two weeks to make it, but would repair mine for less than 10% of the cost of a new one in two days, but no warrantee. Heck that was a no brainer ... the unit was patched inside and out, pressure tested then painted all pretty for $200 bucks, plus R & R.

Sure Like I wouldn't try a repair first and just go for a new part at $2300 a copy.

If I couldn't get it welded in time I intended to epoxy patch it with west epox and glass, sand it down, epoxy glaze it and put it back on and monitor the CO.. But I was able to ge tit welded ASAP.

I've put nearly 60 hours on that new elbo and its still tight and leak free. If I get another 100 hours out of it I'll be so far ahead its silly to think I could have bought a new one.

I have patched a riser on a small Yanmar in my past boating life with petit epoxy putty and glass fiber, and that patch held for 5 years!

In your shoes I'd patch it, but do have the repair shop pressure test it so you don't off yourself from other leaks just about to pop.

When you want some help with DeAngelo, I pass their Lauderdale shop several times a week. I can stop in no problem. I can walk in your elbos for repair later if you want.

Good Luck

 

[Four Suns]

Just got back from working on the boat today.... It is looking sweeeeet for the trip.

These are not the elbows but just straight stainless pipe. The elbows are fairly complex with internal baffles for the raw water return and stuff. I can see those things being expensive. Fortunatly, these are just plain ole' 8" x 20" stainless pipes. No sensors, no gingerbread.... Surely these are not $2300 items... I just spent that on raw water pumps... SURELY THESE ARE NOT THAT EXPENSIVE (trying to convince myself).

I looked at them again today and the starboard engine is the only one with this rust through. The other one looks fine. There is also a lot of metal left and the damage is very localized so I think the thing to do is repair it. However... it's right under the hose clamp so the welded patch is going to have to be ground down smooth to get a good seal. I assume they will cut out this rust and put a patch in it.... but I'm not a welder. I think that's really the thing to do. Heck... surely there are welders in this area with the Newport News shipyard and all...

As a note, there is a bonding connection on the stainless elbows but not on these pipes... I'm going to have lugs welded on each one and connect them to the bonding system in hopes that will slow down this process.

 

[Asureyez]

Less Pricey for sure

Yes, your stove pipes should cost less a lot less, but a weld will be just as satisfactory. Make sure the shop that does the weld uses the correct rods for use in constant contact to salt water ...

When it comes time to get new ones, there is a new shop here in Lauderdale owned by expats of DeAngelo that are more aggressive on price and delivery.

These tubes on my buggy are made of fiberglass ...

 

[Asureyez]

Less Pricey for sure

Yes, your stove pipes should cost less a lot less, but a weld will be just as satisfactory. Make sure the shop that does the weld uses the correct rods for use in constant contact to salt water ...

When it comes time to get new ones, there is a new shop here in Lauderdale owned by expats of DeAngelo that are more aggressive on price and delivery.

These tubes on my buggy are made of fiberglass ...

 

[Dave M.]

I didn't sleep at all last night thinking about these stupid pipes... Now here's how you know you have a boating addiction problem when you "feel guilty" and wonder all night "what could I have done different" and "how could this happen to my baby"... etc...

:smt009 I'm afraid your disease is not treatable.

It's interesting to note that some things on the engine are connected to the bonding system via green wires or they have zincs directly in them. Each engine has 7 zincs along with various green wire connections to the bonding system. This tube has nothing and is isolated with exposure to saltwater with the bottom few inches sitting in saltwater all the time. Could this be the issue? Should there be a green wire connection here or maybe even a zinc?

As I understand galvanic corrosion, it takes two different metals, in contact with each other and an electrolyte, to get galvanic corrosion. As I understand your description, this tube is not in contact with any other metal, so should not suffer from galvanic corrosion.

In the first picture of your post, I have wondered what the spiral dark lines are around the outside of the tube. Does the hose have an internal steel spiral winding inside the rubber compound to help it hold its shape? If so, then is it possible that the clamps over the hose have pinched the hose enough that the winding came through the hose on the inside and touched the metal tube and also the metal at the other end of the hose? If so, the tube would no longer be electrically isolated, and would be subject to galvanic action. Also, in that case getting the tube repaired you will only be fixing the symptom, not the problem.

Just a WAG, but thought I would mention it.

 

[Four Suns]

It is not a spiral seam. The seam is straight and runs the length of the tube and these holes are not around the seam. I saw this written up from David Pascoe's web site:

Leaks: Stainless exhaust system parts are welded, and welds are weak parts as far as corrosion goes. And many of them are only welded from the outside because it's hard to weld on the inside of a pipe. Ergo, leaks usually occur at weld joints. One very good thing about stainless is that it does not generally corrode, but rather pits in unexplainable random places. Meaning that there can be a little hole smack in the middle of a bunch of nice clean steel for no apparent reason. You don't need to know why this happens, only that it does. The really nice part is that Mr. Goodwrench can take that part off, back to his shop, and just weld that little old hole up. Presto! And put it back on. That part may last indefinitely. You like it and I like it.

 

[fwebster]

The dark spiral lines are more than likely residue from Mercruiser Perfect Seal (sealant) used in initial assembly. The residue becomes spiraled as the hose and tube are twisted when separating the 2.

The seam in Garys tube is just that. There is a seamless tubing and a seamed tubing.........seamless is a more expensive and is normally used when something must fit inside a tube. With seamed tubing there is a small seam inside the tube which prevents something from fitting inside........seamed tubing would be the better choice for exhaust parts since nothing fits inside and because of cost.

And, for once, I agree with Pascoe..........

 

[Dave M.]

OK guys. thanks! That makes good sense. That thought had been nagging at me for a while, so had to scratch the itch.

 

[never monday]

I don't understand why this wasn't in the bonding system. That part of the install would fall under the boat builder responsibility with guidance from the engine builder.
I'd guess the corrosion was from sitting in hot salt water without bonding.

 

[Four Suns]

Well... an update here...

I found a machine shop this morning that did stainless work and they said they could fix the pipe. They were going to media blast it and then weld a patch in and grind it down smooth on the outside. I get it back tomorrow and we'll see how they do. They also said it did not need replacing... but...

I got a call back today from the OEM on the part (Deangelo) and the price for a new one is $225.00. The guy left me a voice mail and said the original material was 225 but they had some newer alloy for $425 per pipe that would last much longer. They would would need some time to manufacture them and I don't have time right now. I didn't call them back yet... May do that after our trip but want to see how the welding turns out.

The "patched" pipe will have a connection to the bonding system.