Originally Posted by Minnewaska
If you remove the elbow annually, clean it out and replace it, is the SS really necessary?
For SS to be effective, it requires the presence of oxygen so the chromium oxidizes and creates a protective barrier. Otherwise, its just brittle steel. Not sure how that would happen inside the elbow. I don't inherently understand the need for a SS exhaust elbow, which typically corrode from the inside anyway.
Has anyone ever thought of using high temp powder coating on the interior of an elbow?
We've replaced the elbow on our current and previous boat (both "Pathfinder" VW Rabbit based engines). In both cases, the original non-SS elbows were not plugged or built up, but had simply, as you say, rotted from the inside out. The first we built out of SS sched 40 pipe and fittings, and AFAIK
is still going strong 10-12 years later.. Our current one was fabbed with thinner walled tubing (to better match the exhaust hose ID) so I'll be keeping an eye on that; it's a year old now.