Thanks for the explanation of what to expect from those 30 mm nuts. I found out that the draw-bolt style that we both have was earlier production, with later ones using the bolt-on cap, similar to that on the steam boiler. Also steam boiler apparently was a not-uncommon fix for stripping the "crown" that was welded into the end of the boiler into which the end-cap bolts threaded. I've been literally having to dissolve "bladder stones" that were too big to fit through the ~1 cm hole. I've been using a roughly 2% citric acid w/v solution, available at home brewing shops, for the descale. There are probably faster acids or concentrations, but I've got time... Speaking of time, I decided I could no longer procrastinate and collected the proper equipment for such a task. I looked at the first photo and decided something was wrong. Let's see, big wrenches, penetrating oil, torch, beer. Hmmm, is it that you shouldn't drink and operate incendiary devices? Was it that I was about to wave a torch over the nut that had been doused in oil? The alcohol in the beer inflammable? The beer, yes, that was the problem. Hard to find good Australian beer here, but I did find a more appropriate lubricant... As fun as the torch would have been, the large wrench and a heavy rubber mallet took the nut off quite easily. I'm not sure your dispersion heads are significantly different than mine. I've got some of the holes on one that come up through the back side of the "sockets" for the removal pin spanner. I may try to take apart one of the groups tonight. While I probably could get away without re-chroming, there are a couple gouges on one of the groups where the cover scraped against the group, as well as some spots on the valve nuts where it looks like pliers were used instead of a spanner. At least you can get powder coat redone; someone screwing up the castings prior to plating scares me. Sounds like yours is going back together soon!
