Water injection exhaust elbow

[CalicoJack]

During the summer (ha, ha) I needed to have a new elbow made quickly, so I had it made out of mild steel. Since then I have had a posh one made out of Stainless. Having now fitted the stainless one I was surprised how little corrosion had taken place in the mild steel elbow. I was wondering whether it would be worth getting the mild steel one galvanised, or whether this would just be a waste of time and money as it would not prolong its life sufficiently? Any thoughts?

 

[nimbusgb]

It's warm when you turn the engine off and it's not bathed in water so it dries off every time you use it. Even a thin mild steel car exhaust lasts 5 years or more.

A galvanised version might last quite a few years!

The Ali elbow on my 4-108 only lasted 20 years.

 

[vyv_cox]

There has been some discussion recently about the composition of production exhaust elbows. As far as I know, without having tested any, Volvo, Bukh and Yanmar elbows are all made from steel, of one variety of another. 300 series stainless steel is susceptible to corrosion by hot chlorides and you may well find that a mild steel one will last just as long.

So far as galvanising is concerned, I have no information. An opportunity for you to carry out some original research maybe?

 

[rob2]

Inside an exhaust elbow you've got a set of pretty aggressive environments! The inner pipe has burning exhaust gases inside it and seawater being sprayed on the outside - I wouldn't expect galvanizing to last too long in that regime. I was reminded, though, of being told that black iron pipes for seawater use are heated to cherry red and then immersed in oil to prevent rusting. Anyone care to try that?

Rob.