Weld on galv/black iron exhaust riser

May 8, 2014
31
sailboat about 37' SE US
I'm replacing my steel pipe exhaust riser with another one and want to know if there is any problem welding the water injection nipple to the pipe.

Plan on using galvanized or black pipe and instead of a T, i am thinking of just welding on a nipple for water injection downstream from highest point. I know SS has problems with welds in exhaust risers, but does mild steel also have issues?

thanks
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
as cheap as it is going to be why worry you can always do it again when it goes bad.... you can weld ss to black iron if you use 309 stainless filler rod if you are stick welding... if you are tig welding use 316 filler rod
 
Jan 22, 2008
1,666
Hunter 34 Alameda CA
I'm replacing my steel pipe exhaust riser with another one and want to know if there is any problem welding the water injection nipple to the pipe.

Plan on using galvanized or black pipe and instead of a T, i am thinking of just welding on a nipple for water injection downstream from highest point. I know SS has problems with welds in exhaust risers, but does mild steel also have issues?

thanks
My water injection nipple has gotten plugged on several occasions with mud. I'll start the engine and no cooling water comes out of the exhaust. I shut down and after removing the hose, find the entire nipple is blocked. I remove it and have to use a screwdriver and ice pick to chip stuff out as its like concrete. I'd rather not introduce that stuff into the exhaust/muffler, so I prefer the ability to remove it. You could weld a female 1/2 coupler on the exhaust and then be able to remove/replace a bronze barbed male adapter.

Just my $0.02.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
My water injection nipple has gotten plugged on several occasions with mud. I'll start the engine and no cooling water comes out of the exhaust. I shut down and after removing the hose, find the entire nipple is blocked. I remove it and have to use a screwdriver and ice pick to chip stuff out as its like concrete. I'd rather not introduce that stuff into the exhaust/muffler, so I prefer the ability to remove it. You could weld a female 1/2 coupler on the exhaust and then be able to remove/replace a bronze barbed male adapter.

Just my $0.02.
that's a good suggestion allan or he could find a i/2 inch female welding boss and weld it on they are a lot thicker in the wall construction and will hold up better
 
May 8, 2014
31
sailboat about 37' SE US
Ah, yes, allan, that is a good idea. I'll look for one. Thank you for the advice.
 
May 8, 2014
31
sailboat about 37' SE US
OK, let's take this a step further.

Assumption 1: black iron or galvanized pipe are the only types of pipe appropriate for exhaust riser.
Assumption 2: I know how to weld (stick weld)
Assumption 3: zinc fumes can be mitigated during welding if I chose galvanized pipe.

So, once i have a pvc mock-up and see that the angles are not exactly square, why should I not just get some pipe and fittings, then cut and weld them together to make the riser have the perfect angles out of the flange and into the water lift?

I know that SS weld joints have a big problem with crevice corrosion, especially in an exhaust system, but are there any deficiencies created during welding of black iron/galvanized pipe that make the weld joints inferior to the non-welded pipe, in the context of the exhaust riser?

Right now, my pvc mock-up shows that the downward part is not directly over the intake of the waterlift and it is not parallel to the intake of the waterlift. It's off by about 1/2 diameter (1.5" pipe) and the angle is, maybe, about 15 degrees out of plumb.

Would it be simpler and more reliable if I threaded the pipe and fittings together and got a length of hose (hump hose or whatever) to bend over from the exhaust riser down into the waterlift intake or cut and weld the pieces so the down part of the riser meets the waterlift directly form above and parallel?
 
Jan 22, 2008
1,666
Hunter 34 Alameda CA
that's a good suggestion allan or he could find a i/2 inch female welding boss and weld it on they are a lot thicker in the wall construction and will hold up better

Nice Woodster. I wasn't aware of that specific piece.
 
Jan 22, 2008
1,666
Hunter 34 Alameda CA
OK, let's take this a step further.

Assumption 1: black iron or galvanized pipe are the only types of pipe appropriate for exhaust riser.
Assumption 2: I know how to weld (stick weld)
Assumption 3: zinc fumes can be mitigated during welding if I chose galvanized pipe.

Yes, but are they mitigated during engine running?? Stick with black iron if possible.

So, once i have a pvc mock-up and see that the angles are not exactly square, why should I not just get some pipe and fittings, then cut and weld them together to make the riser have the perfect angles out of the flange and into the water lift?

I know that SS weld joints have a big problem with crevice corrosion, especially in an exhaust system, but are there any deficiencies created during welding of black iron/galvanized pipe that make the weld joints inferior to the non-welded pipe, in the context of the exhaust riser? I don't see why welding after screwing the pieces together would compromise the integrity of the materials. It would keep them from loosening with vibration. I've seen lots of black iron gas pipe that was welded.

Right now, my pvc mock-up shows that the downward part is not directly over the intake of the waterlift and it is not parallel to the intake of the waterlift. It's off by about 1/2 diameter (1.5" pipe) and the angle is, maybe, about 15 degrees out of plumb.

Would it be simpler and more reliable if I threaded the pipe and fittings together and got a length of hose (hump hose or whatever) to bend over from the exhaust riser down into the waterlift intake or cut and weld the pieces so the down part of the riser meets the waterlift directly form above and parallel?
The hose interface makes the most sense.


Check out this beauty that saved us on a cruise out. I know I used galvanized and after a week it pretty much burned off. In retrospect it probably wasn't the best decision.
 

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