Making your own exhaust elbow - why not

[skyflyer]

About the time my boat was made the manufacturer changed engine supplier and as a lift loop was required, the engine being well below the water line, they had made a fairly basic exhaust elbow, like this one

The water injection point is on the opposite side of the tube to the writing C-320
Before use, of course, it has to be lagged between the engine exhaust port and the water injection point, to protect against heat

Since then those nice people at Yanmar have made some standard parts to do the same job, like this

The entire assembly will cost upwards of £500 to replace!

So - following suggestions in this forum - I got in touch with Ben Cotton in the US and he will custom build one in the same style as the original for around $200 but because it S a custom build we are having problems with measurements - ideally he'd like the old one to work from but obviously that isn't really practical due to the distance and time it would take.

So i got to wondering why couldn't I get a welder to make up one for me, in the UK for scratch?

Even more so when I found that this part, in 316L stainless

costs just £5.50 !

How difficult can it be to put something like this together. Essentially the materials are going to cost under £30.

What am I missing?

Where do i finda competent welder who can make good gas-tight joints - is that the catch?

 

[Heckler]

About the time my boat was made the manufacturer changed engine supplier and as a lift loop was required, the engine being well below the water line, they had made a fairly basic exhaust elbow, like this one

The water injection point is on the opposite side of the tube to the writing C-320
Before use, of course, it has to be lagged between the engine exhaust port and the water injection point, to protect against heat

Since then those nice people at Yanmar have made some standard parts to do the same job, like this

The entire assembly will cost upwards of £500 to replace!

So - following suggestions in this forum - I got in touch with Ben Cotton in the US and he will custom build one in the same style as the original for around $200 but because it S a custom build we are having problems with measurements - ideally he'd like the old one to work from but obviously that isn't really practical due to the distance and time it would take.

So i got to wondering why couldn't I get a welder to make up one for me, in the UK for scratch?

Even more so when I found that this part, in 316L stainless

costs just £5.50 !

How difficult can it be to put something like this together. Essentially the materials are going to cost under £30.

What am I missing?

Where do i finda competent welder who can make good gas-tight joints - is that the catch?

I did it myself for my MD22. Used basic elbows, available in 316 SS from an outfit in Chester. Got a local welder to weld it. Used an inj bit from ASAP. Was quite straight foward. Motored across Biscay for two straight days. No issues
S
PS I actually used 1.5" threaded bits and only welded to the flange

 

[NormanS]

I was suspicious about the condition of the exhaust elbow on my Volvo MD22 (Perkins Prima). I toyed with skipper_stu's idea using a water cooled elbow from Asap. On further investigation, the actual elbow still has some life left in it, but the water injection elbow was totally rotten, and actually fell apart in my hand. This small water elbow is apparently made of something more expensive than gold, so I made one myself.

To be on the safe side, I fabricated a mild steel exhaust elbow, with water connection, which is lying in the bottom of a locker, so that if or when the original cast elbow fails, I can easily replace it.

 

[Spyro]

I've wondered why if ben Cotton is making them in the US and obviously making money then why is someone not doing it in the UK. Once a small enginnering outfit had the measurements they could rattle them out in no time. Must be money to be made at the rate the yanmar ones need replaced.

 

[skyflyer]

I've wondered why if ben Cotton is making them in the US and obviously making money then why is someone not doing it in the UK. Once a small enginnering outfit had the measurements they could rattle them out in no time. Must be money to be made at the rate the yanmar ones need replaced.

my thoughts entirely - I have been in touch withs several outfits that do "custom" car exhausts, but when you get don to the nitty gritty they all seem to end up being not that 'custom' at all, in as much as they have several patterns and jigs for particular cars, and use a standard material of a standard diameter in a standard wall thickness.

I think this is borne out of ignorance of what we boaters have to pay for our OEM exhausts. The auto-shops think if they do what I want it will cost more than £50 and I wont want to pay that much!

 

[earlybird]

My high-rise elbow is mainly home-made as its an unusual shape and fits into a tight space.
Four elbows and a piece of tubing, all 1.25" sch.10 S316 cost about £35.
I took the tacked assembly to a local firm of specialist welders since I had no TIG equipment. They charged me £100 for 9 welds.
I'd expect welders to be found fairly easily, food and dairy industry make much use of SS plant.
Having said the above, there's still a need for making the mounting flange, cutting and prepping any straight pieces and drilling for the injection point. S316 isn't the easiest material to work.
I'm fortunate in having a lathe etc. but this work probably took 15 to 20 hours. Paying for that could be quite pricey.
Commercial one-offs will therefore tend to be costly.
Now in its 3'rd season and going strong.
Add; I'd be cautious about car exhaust firms. Much of their material is thin wall S304. any welds might not stand up well to warm salt water in the medium term.
Best to use S316 in this application IMHO.

 

[Poecheng]

Have a read on the MOBO forum of a long thread by Jimmy the Builder http://www.ybw.com/forums/showthread.php?415621-Back-to-the-UK-for-a-winter-refit/page77
(try post #769)
He had a specialist piece made by Pipecraft.

 

[skyflyer]

Have a read on the MOBO forum of a long thread by Jimmy the Builder http://www.ybw.com/forums/showthread.php?415621-Back-to-the-UK-for-a-winter-refit/page77
(try post #769)
He had a specialist piece made by Pipecraft.

Interesting as Pipecraft was one of the first i contacted and theywerent interested - too small a job I guess

 

[Floyd Raser]

I've wondered why if ben Cotton is making them in the US and obviously making money then why is someone not doing it in the UK. Once a small enginnering outfit had the measurements they could rattle them out in no time. Must be money to be made at the rate the yanmar ones need replaced.

Classic car clubs sometimes have hard to get exhausts made in batches to make it economical. Asking for 10 may get them to prick their ears up.

 

[toad]

I made one out of scaffolding tube once, it outlived the engine.

 

[LadyInBed]

I went to a metal fabricator in my local town with an old elbow and got one made up in stainless, it cost about £20.
It's well worth finding a local small welding Co that will do small lunchtime jobs for beer money.

 

[cliff]

Best to use S316 in this application IMHO.

Nope - Best to use 316L in this application

 

[jimmy_the_builder]

Have a read on the MOBO forum of a long thread by Jimmy the Builder http://www.ybw.com/forums/showthread.php?415621-Back-to-the-UK-for-a-winter-refit/page77
(try post #769)
He had a specialist piece made by Pipecraft.

Yep, I had a brilliant job done by Pipecraft, and I'd completely recommend them - details here:

http://www.ybw.com/forums/showthrea...e-UK-for-a-winter-refit&p=5256145#post5256145

 

[GrahamHR]

I've been thinking along the same lines but about the water inlet hose on my D4. I've put a T piece in so I can run it out of the water on a hose / flush it with fresh water when it's afloat. I always worry about plastic T pieces ( even though I am a materials scientist and know a properly made one is very safe !). I was thinking about a custom made silicone inlet hose with an integral side inlet ; cheaper I'm sure than the stupid £140 + price VP want for the original rubber one. They should have fitted one as standard with the side inlet blanked off, so they could supply an optional flush kit at a stupid price ( Standard by the way on US VP V8 and V6 petrol engines since 2003 !)

 

[Sinbad1951]

15 years ago I went to a pipe supplier and bought several bends and a straight piece of 316L pipe. I cut the bends with a hacksaw with a special stainless cutting blade and then created a shape very similar to the OP's first pic. I marked each piece with tipex so that the welding was done at exactly the right place to maintain the curves and shape. I took these cut pieces to a steel machinist which does agricultural work (milking parlours are all stainless and welded) Not only did they produce an excellent water injected elbow but the had enough bits left over they created a duplicate. Total cost £180.
The spare is still in my garage and the original is still perfect. The alternative was a quote from Halyard for £500+

 

[rogerthebodger]

This is my home made exhaust injection elbow and even a home made water cooled manifold

 

[Graham_Wright]

Warren Engineering in Tewkesbury and DC Welding in Ledbury.

 

[Alpha22]

This is my home made exhaust injection elbow and even a home made water cooled manifold

Nice job. (Was the picture taken by a home made camera by any chance?)

 

[Niander]

Any old stick welder will do using S/S rods just need a good welder or learn.

 

[usernamenotvalid]

I spent almost twenty years welding 316 stainless steel bushing pads directly onto mild steel transformer tanks(3-8 mm ss to 3-10 mm ms) with mild steel mig wire and a lot higher argon content gas than I ever remember using in the UK in the eighties. But this gas mix was just what we normally used on mild steel. Got an occasional "blowhole" but that might have been one in ten feet of welding! Even that odd blowhole we could only put down to air being sucked through the back of the unwelded side. So probably not related to mixing metals. Easily Fixed anyway. The steel was powdercoated outside, stainless open to weather. Many located in coastal areas. Never once heard of a failure.
I know they're not getting hot salt water pumped around in them but twenty years old and they looked like, and indeed were as good as new when cleaned up. I would happily have half a dozen steel or galv elbows made up and have spares forever. The scaffolding fittings mentioned earlier sound like the way to go.