I recently acquired a used 2004 La San Marco Practical 85 S (one group) from a restaurant supply auction. This is my first BIG project, so I've been doing a LOT of reading on H-B. When I fired it up to test the heating element, pump, etc. everything functioned well except for a lack of water coming from the brew head (I have, since, figured out that that was caused by, at very least, a HEAVILY scaled-up L-Heat Exchanger Tube - so gunked up that I'm going to replace it rather than try to descale it!). Anyway, I've taken, probably, 200 photos of the teardown already and I'm planning a much more thorough documentation of the teardown and rebuild at some later point.

In the meantime, though, I have a question about descaling. I have read quite a bit on H-B about how descaling can remove chrome plating from parts - that seems uncontroversial. There are three hydraulic parts in the LSM that I have that seem to have some sort of plating on them (besides the group head, of course): 1) both the upper and lower circulation tubes look like they are chrome-plated (but, I'm not sure), which I am less concerned about, and 2) the boiler is nickel-plated.

While taking the boiler apart for a good, total descale, I saw that it is both 1) in great shape inside the boiler and 2) really scaled/mucked up in the heat exchanger itself. I was going to go ahead and give everything a good descale bath for safety-sake, but, I'm wondering if this is going to 1) strip the nickel plating and if it WILL strip it, if 2) there are any precautions that I can take to avoid this happening (lower proportion of citric acid? shorter time in the solution?)?

Thanks!

You don't seem you be getting much traction on this, so I'll toss in my fairly nubee two cents worth.

For chrome or nickel, and possibly other, plated parts, a 50/50 white vinegar solution seems to be best. I just did one on the Giotto project and it came out fairly good. A little bit of pink showed up(after 4 soakings,including 2 in citric) that polishing mostly removed. My guess is that most of the pink was due to the citric.

I just acquired a La Cimbali Junior that appears to have a plated boiler and am planning on trying just vinegar this time.

Thanks for the recommendations, David. Right now I'm having trouble removing one of the external fittings that holds the heat exchange tube inside the boiler, so, I'm trying to do a bit of delicate, in situ descaling. If that fails (and, I suspect it will) I will probably be dumping the whole thing in a 50/50 vinegar bath and see how it goes. I'll follow-up since others might look for this information at some point in searching the H-B archives ...

Sounds good, unfortunately I have no experience with the La San Marco line. Hoping a decent fixer-upper falls my way at a good price, as I do like the look of the things.

Hi Jack,
In answer your question on my thread about the 85 Practical, there were not any reverse threads but if I recall correctly I had to use quite a bit of force when removing the heat exchanger.

Also the boiler you see in my images was soaked in a citric acid solution for many days without damage to the nickel, though I did keep an eye on it. I have found that the acid will deposit a thin coating of copper onto chrome and nickel surfaces but this easily comes off with some steel wool.

Thanks so much, Larry! I was able to very slowly and carefully and systematically descale each bit-and-piece of the boiler without soaking the whole thing in descaler (which, strictly, would have been unnecessary since so much of it was nearly immaculate when I opened up the boiler). Since I was having such trouble with the heat exchange tube, I ended up plugging one end with a wine cork and filled it with a stronger-than-normal citric acid solution (since that tube was, by far, the location of the worst scale in the whole machine), pouring in hot solution, letting it sit for a few hours, then flushing it, and using a pipe-cleaning brush to scrub it out ... then repeating the procedure several more times. In the end, it turned out great -- absolutely no scale left in there.

The last big descale/cleaning challenge will be the group head (which, I just removed from the frame last night). Hopefully no other weirdness ...

Cheers!

Sounds like you are making good progress, have fun!