And that is a great question 62MaxWagon. I (and Waldron's do I believe) use a 304 st. st valve plate mating with 409 st. st. tubing. The dissimilar materials keeps the sticking from occurring; indeed, it did in 1969-1971 when the parts were all 409 st. st. Both of these stainless steels are resistant to rusting all the way away. St. st. 409 builds up a surface condition of light discoloration/oxidation that then tends to stay put.

With the new fuels we have, the issue is not like it used to be in 1970. Plus, none of us fire up the car and listen and then shut them off. Okay, so I do to show off the mufflers' sound but I have no worries about them sticking as know what I did to them internally. Most of us tend to drive the cars and evaporate the moisture from the mufflers more so then what people used to do when these cars were new and used for transportation. A small hole will help if you just start and then shut the engine off.

My mufflers are now going on 6 years old. The originals in 1970 lasted about two to four years max (I heard) but tended to stick and required you to tap the end now and then to break them free. The new generation versions do not.

The cool thing is they stay closed while they sit and when they open or close upon driver control, they chatter briefly while seating and unseating the valve. The videos may allow you to hear the very brief rattle. That comes from the plate being free to float on its shaft letting it always take the correct angle needed to seat. This slight chatter also tends to polish away anything that may be starting to build up and change the surface and cause sticking issues.

The actuator is the part than can wear out but it is outside and easy to replace. A few of the very early ones needed a modification to the rivet that held the arm on the rubber diaphragm but that part is well understood and the engineering change was instituted several years ago.

I have attached the original patent illustration. You can see how they worked originally. The changes we made simplified them and made them much better, longer lasting, louder when open, and quieter when closed. Plus they flow more exhaust gases when open, and the new materiel we used makes them virtually "forever" mufflers, not short lived ones like they were in 1969-1970.

Tom Hand