Anyone noticed how on cars radiators, after a period of time, the fins crumble away? There is a process, when getting a radiator re-cored, called flux paste and bake. Basically, what happens is the radiator core is 'painted' with soldering flux and the entire core is then baked, resulting in all surfaces becoming 'tinned'. This tinned surface prevents the copper from oxidising over time, alleviating the crumbling fins.
My 23 is pretty well all original. It has the original radiator [boiler]. From what I understand, the efficiency is markedly reduced when the fins are no longer tight on the tubes. My radiator has this malady. However, it looks very sound. I certainly do not want to recore it. What I'm wondering is if the core could be removed from the tanks, cleaned sufficiently to allow it to be flux pasted and baked, thereby getting a good bond betwix tubes and fins with an improved heat transfer then happening.
Here is part one of a multipart video showing the process of a new radiator.
Brian, as you mentioned, getting it clean. I think that would be the biggest problem. I try and do most of my own radiator repair and I always say clean, clean and then clean some more. Also baking the entire radiator will cause all the solder to turn loose and you don't want that to happen. Not saying it can't be done but probably not time or cost efficient . KGB