I have read a few things on this site describing building an exhaust assemby using black pipe from Home Depot. I want to do this as my exhaust elbow needs replacing. I plan on using 1 1/4 inch black pipe and black pipe ells and 45's. My question is, can I simply assemble the niples and couplings using never seize and a pipe wrench and vice or do I need to weld (braze)each connection?
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no welding necessary
Just tighten it up so you won't have any exhaust leaks and you're good to go. I have heard not to use teflon tape here because at high temperature it might emit a noxious gas. I don't know about never seize.
Just tighten it up so you won't have any exhaust leaks and you're good to go. I have heard not to use teflon tape here because at high temperature it might emit a noxious gas. I don't know about never seize.
sounds good, but...
Since black pipe is iron I'd inspect it from time to time to insure that it wasn't on the brink of corroding thorough. Besides the obvious risk of carbon monoxide the system would begin to leak large amounts of water into the engine compartment. It's a good idea but I'd inspect it at least annually for corrosion. Just my two cents. Good luck with the project. Mike
Since black pipe is iron I'd inspect it from time to time to insure that it wasn't on the brink of corroding thorough. Besides the obvious risk of carbon monoxide the system would begin to leak large amounts of water into the engine compartment. It's a good idea but I'd inspect it at least annually for corrosion. Just my two cents. Good luck with the project. Mike
Schedule 80
ABYC Section ‘P-1", Exhaust Systems specifies a minimum of Schedule 80 (extra heavy wall) pipe for THREADED Exhaust Systems. Table I lists permissible materials. By comparison: 1-1/2" Dia. Schedule 40 pipe has a wall thickness of 0.145". The required 1-1/2" Dia. Schedule 80 pipe has a wall thickness of 0.20" (more than 1/3 thicker). The exhaust system must be leak tested to 4 psi (28 kPa).
ABYC Section ‘P-1", Exhaust Systems specifies a minimum of Schedule 80 (extra heavy wall) pipe for THREADED Exhaust Systems. Table I lists permissible materials. By comparison: 1-1/2" Dia. Schedule 40 pipe has a wall thickness of 0.145". The required 1-1/2" Dia. Schedule 80 pipe has a wall thickness of 0.20" (more than 1/3 thicker). The exhaust system must be leak tested to 4 psi (28 kPa).
Home Depot
Consider that I'm not a mechanic, so take this for what its worth. Home Depot has about the lowest quality of anything you can think of. It sells inferior lumber and supplies as well as inferior ropes, etc. Do we even know where the iron pipe was manufactured, starting with the raw materials? Do you really want this on your boat? Just my 2 cents worth. Tony B
Consider that I'm not a mechanic, so take this for what its worth. Home Depot has about the lowest quality of anything you can think of. It sells inferior lumber and supplies as well as inferior ropes, etc. Do we even know where the iron pipe was manufactured, starting with the raw materials? Do you really want this on your boat? Just my 2 cents worth. Tony B
Black Pipe
Three years and looking goood on my C-30. I'd do it again. My black pipe screwed right into the exhaust manifold. I used no sealants, just screwed it tight. Wrap the pipe with fiberglass exhaust wrap. It takes about 20' of 2 inch wide wrap. Sean
Three years and looking goood on my C-30. I'd do it again. My black pipe screwed right into the exhaust manifold. I used no sealants, just screwed it tight. Wrap the pipe with fiberglass exhaust wrap. It takes about 20' of 2 inch wide wrap. Sean
Pipe Dope
I worked for a gas utility for 34 years and have used pipe dope for all connections of black iron pipe. It's not only for the leak value but also for the lubricted effect of the threads. Most of the pipe dope is able to with stand high temps of the exhaust system. Those that are put together with no dope after awhile become so tight and siezed that it takes a 36" wrench just to get them a part. I have to rebuild my exhaust system for a Universal M-18 and I'll use the anti seize on the bolts and nuts at the manifold connection and dope for all the others then wrap it in the heat sheild from K S auto the 1" is easier to wrap than the 2". This can all be done out of the boat and then insalled. Good luck and happy sailing.
I worked for a gas utility for 34 years and have used pipe dope for all connections of black iron pipe. It's not only for the leak value but also for the lubricted effect of the threads. Most of the pipe dope is able to with stand high temps of the exhaust system. Those that are put together with no dope after awhile become so tight and siezed that it takes a 36" wrench just to get them a part. I have to rebuild my exhaust system for a Universal M-18 and I'll use the anti seize on the bolts and nuts at the manifold connection and dope for all the others then wrap it in the heat sheild from K S auto the 1" is easier to wrap than the 2". This can all be done out of the boat and then insalled. Good luck and happy sailing.
Exhaust Elbow
No one seems to be describing a water injection exhaust with an exhaust elbow fitting. Typical original equipment exhaust systems on the smaller diesels would incorporate an exhaust elbow where seawater from the downstream side of the water lift muffler is introduced into the exhaust to cool it. Why would you want to do a Rube Goldberg installation on an exhaust system and risk higher heat and/or exhaust fume problems. The exhaust elbow and water injection nipple on my 2GM20F are 20 years old and have needed cleaning once to remove carbon build up in the exhaust elbow 'U' shaped casting.
No one seems to be describing a water injection exhaust with an exhaust elbow fitting. Typical original equipment exhaust systems on the smaller diesels would incorporate an exhaust elbow where seawater from the downstream side of the water lift muffler is introduced into the exhaust to cool it. Why would you want to do a Rube Goldberg installation on an exhaust system and risk higher heat and/or exhaust fume problems. The exhaust elbow and water injection nipple on my 2GM20F are 20 years old and have needed cleaning once to remove carbon build up in the exhaust elbow 'U' shaped casting.
Water injection
I did mine with HD parts and incorporated water injection 2 years ago and it is still working great. PO told me he did it when he bought the boat and it lasted to when I bought it 12 years later. I replaced because it was clogged which will happen on any system. I paid about $100. My friend paid $1000 to the local yard. Tim R.
I did mine with HD parts and incorporated water injection 2 years ago and it is still working great. PO told me he did it when he bought the boat and it lasted to when I bought it 12 years later. I replaced because it was clogged which will happen on any system. I paid about $100. My friend paid $1000 to the local yard. Tim R.
Thanks for all responses
Wow, great responses! I appreciate you all taking the time to advise me. I will use schedule 80 black pipe, I have a scource already, and I will of course incorporate water injection on downhill side and 1 inch glass wrap. Thanks again for the help mates.
Wow, great responses! I appreciate you all taking the time to advise me. I will use schedule 80 black pipe, I have a scource already, and I will of course incorporate water injection on downhill side and 1 inch glass wrap. Thanks again for the help mates.
home depot quality
seems to be bottom of the barrel here in michigan, lumber warps almost as you're loading it on the truck. every bolt I've ever bought from them seems to have issues of some sort or the other, nuts fit loosely, or bind up halfway up the bolt, don't get any hardware or lumber there, regular lumber yard when quality is an issue, or menards when price is, qualities the same as home depot, but price fits it. when sorting lumber it's common to have someone say to pull out all the home depot boards, which is to say get rid of all the warps and splits, and so far I've never heard anyone ask what was meant. A home depot 'huh?' quite often you'll see them with odd sized lumber for sale at nice prices, last I saw was 2x4 7ft for $1.98, why? what good is a 7ft 2x4? too short for cripples, too much scrap when cut for blocking or sills, no good for studs etc, strangely, every time I see them the 2x4x7ft sign is on the back, with a 2x4x8ft sign sitting on the floor in front of the stack. Black iron does work well as an exhaust system, anti sieze works wonders, use it all the time on exhaust manifolds for offroad/mud run trucks, never had any issues with it. Always made me wonder though, as most anti sieze compounds are copper in a grease base, grease alone doesn't work, and putting different metals together is the surest way to sieze it up, so it always leaves me saying huh? Ken.
seems to be bottom of the barrel here in michigan, lumber warps almost as you're loading it on the truck. every bolt I've ever bought from them seems to have issues of some sort or the other, nuts fit loosely, or bind up halfway up the bolt, don't get any hardware or lumber there, regular lumber yard when quality is an issue, or menards when price is, qualities the same as home depot, but price fits it. when sorting lumber it's common to have someone say to pull out all the home depot boards, which is to say get rid of all the warps and splits, and so far I've never heard anyone ask what was meant. A home depot 'huh?' quite often you'll see them with odd sized lumber for sale at nice prices, last I saw was 2x4 7ft for $1.98, why? what good is a 7ft 2x4? too short for cripples, too much scrap when cut for blocking or sills, no good for studs etc, strangely, every time I see them the 2x4x7ft sign is on the back, with a 2x4x8ft sign sitting on the floor in front of the stack. Black iron does work well as an exhaust system, anti sieze works wonders, use it all the time on exhaust manifolds for offroad/mud run trucks, never had any issues with it. Always made me wonder though, as most anti sieze compounds are copper in a grease base, grease alone doesn't work, and putting different metals together is the surest way to sieze it up, so it always leaves me saying huh? Ken.
Ken, can't relate.
Our HD is great. No such problems. When they opened here a few years ago they drove the other guys out of business because of their lumber quality. I bought a quarter mile worth of 4x4 post for horse fence. All of them were perfect. I tried to sort so as to pick and choose but for the low price they were 'beating', I had to take the pallet. No sweat. Maybe you are seeing the dredges after people have sorted through the stacks? And I've never heard of a 7 foot 2x4. Weird. And it seems strange that your store could sell swill and not have it all come back to them,,,
Our HD is great. No such problems. When they opened here a few years ago they drove the other guys out of business because of their lumber quality. I bought a quarter mile worth of 4x4 post for horse fence. All of them were perfect. I tried to sort so as to pick and choose but for the low price they were 'beating', I had to take the pallet. No sweat. Maybe you are seeing the dredges after people have sorted through the stacks? And I've never heard of a 7 foot 2x4. Weird. And it seems strange that your store could sell swill and not have it all come back to them,,,
Don't weld
I rebuilt the exhaust elbow last year with black pipe. Fitted it all together, then had the connections brazed. In spite of it duplicating the 15 year old original of black pipe, it was off a bit. The rubber hose to the fiberglass muffler inlet was able to take up the slack, but would have eventually broken the inlet. Cut pipe, rewelded, again I was not happy with the ultimate fit. Redid the whole thing without the welding, was able to make minor adjustments to get a perfect fit. No leaks, no stress on the muffler inlet, and cost was about $10 here in Mexico (forgot about other assembly and welding costs) Works great, happy motor and skipper.
I rebuilt the exhaust elbow last year with black pipe. Fitted it all together, then had the connections brazed. In spite of it duplicating the 15 year old original of black pipe, it was off a bit. The rubber hose to the fiberglass muffler inlet was able to take up the slack, but would have eventually broken the inlet. Cut pipe, rewelded, again I was not happy with the ultimate fit. Redid the whole thing without the welding, was able to make minor adjustments to get a perfect fit. No leaks, no stress on the muffler inlet, and cost was about $10 here in Mexico (forgot about other assembly and welding costs) Works great, happy motor and skipper.
I'm a HD regular.
I've never been disappointed with anything I buy there. We have 2 that are nearby. I also buy regularly from the neighborhood lumber yard because their product selection, convenience, service and know-how is great (at somewhat higher cost). There is a niche for both.
I've never been disappointed with anything I buy there. We have 2 that are nearby. I also buy regularly from the neighborhood lumber yard because their product selection, convenience, service and know-how is great (at somewhat higher cost). There is a niche for both.
US made fitings
Black pipe is not all the same .The stuff HD sells is thin .the original 90o elbows where thicker and where rated for steem boilers you can find this pipe in old plumbing shops.I had a guy at a muffler shop make up a riser out of SS 11/4 muffler tube they use the stuff for the new super charger moters. John
Black pipe is not all the same .The stuff HD sells is thin .the original 90o elbows where thicker and where rated for steem boilers you can find this pipe in old plumbing shops.I had a guy at a muffler shop make up a riser out of SS 11/4 muffler tube they use the stuff for the new super charger moters. John
MIne is good after two years
but for the cost, I carry a spare set of parts just in case something fails. I drilled a spare injection pipe when I made the first one so I have a backup of that too without having to make it on the boat. I inspect it at each oil change: Remove the cooling water line and unscrew the double tapped bushing. Look inside and check for corrosion or coke buildup. Mine has a little corrosion but never has had coke buildup. 1 1/2 inch pipe not 1 1/4 on mine. I just used a little high temp (non teflon) antisieze from the auto supply store on each part and did not tighten them really tight with a pipe wrench. I used channel lock pliers to put it together but have a pipe wrench just in case. No welding on mine. You could weld the inside water pipe to the bushing but that might fail and I do not have a welder to fix it with on the boat. So I just got a double tapped bushing which I can replace easily. The only hard to find part is that double tapped bushing which a plumbing supply did have here. Mine cost about $7 and the rest of the parts a little over $10 as I remember. The engine runs much better than with a Yanmar part that one sob supplier quoted me at $480 plus tax. I hate Yanmar parts people.
but for the cost, I carry a spare set of parts just in case something fails. I drilled a spare injection pipe when I made the first one so I have a backup of that too without having to make it on the boat. I inspect it at each oil change: Remove the cooling water line and unscrew the double tapped bushing. Look inside and check for corrosion or coke buildup. Mine has a little corrosion but never has had coke buildup. 1 1/2 inch pipe not 1 1/4 on mine. I just used a little high temp (non teflon) antisieze from the auto supply store on each part and did not tighten them really tight with a pipe wrench. I used channel lock pliers to put it together but have a pipe wrench just in case. No welding on mine. You could weld the inside water pipe to the bushing but that might fail and I do not have a welder to fix it with on the boat. So I just got a double tapped bushing which I can replace easily. The only hard to find part is that double tapped bushing which a plumbing supply did have here. Mine cost about $7 and the rest of the parts a little over $10 as I remember. The engine runs much better than with a Yanmar part that one sob supplier quoted me at $480 plus tax. I hate Yanmar parts people.
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