I have the aforementioned espresso machine and it sees daily use as I would hope all home machines do. My machine sits under a cabinet in a dry corner of the kitchen, next to my grinder.

As my machine is only 1 year and a couple months old, I tend to baby it and clean it more than any other appliance we have much to my wife's chagrin.

The other day I noticed some spotting on the surface of the inside panel of the machine where the warming rack is and where you generally keep your cups waiting. I thought perhaps I had spilled coffee somehow, but then realized the impossibility of this happening. I attempted to wipe of the spots, but then I believe I came to the conclusion that this is rust? Is that possible? I know the panels are supposed to be stainless steel, but the inside of the panel is completely different from the outside and I don't think it is treated the same way.

Is this a serious issue and what should I do?

underside of warming tray


panel shot (all affected areas are in the same location)

I agree it looks like rust. I'm guessing the stainless steel was only polished on its outward face. Stainless steel comes in different grades to meet different design needs, and with differing anti-corrosion properties as well. This may help: http://www.stainless-online.com/why-sta...inless.htm

The photos appear to be of the rear right corner of the machine. The water reservoir is here so it may be a very moist area. However, I would say the rust you see is atypical. I have zero on my 1.5 year old machine in any location. It looks like you maybe got unlucky with a few sheets of either poor quality SS or it has been processed improperly and lost some of it's non-rusting atomic properties. Seeing as there are no welds and only bends in those general locations, my guess would be the former. I'd contact your vendor to see about panel replacements.

Have you contacted the vendor you purchased it from? They can check with the manufacturer to see if there was/is a known issue with the steel used in that particular production run. I'd start there. This does not look like the norm. My Isomac is 8 years old and doesn't have a speck of rust anywhere.

Just to note, all welds are subject to rusting. Different machines have different grades of stainless. The Isomac Tea and Millenium use a higher quality stainless when compared to the lower grade stainless on the Venus, Super Giada or Maverick lines. I just want to mention this because I do not want future readers to think all Isomac espresso machines have the same grade.

Although I am not a metallurgist, I have learned that non-rusting stainless tends to be thicker walled because it does not have the structural integrity of a stainless steel that rusts (which have thinner walls).

There are many formulas for stainless as well as treating methods. One thing to keep in mind, stainless steel is not rustless steel. It is very rust resistant but there is a reason it is called stain-less steel, not rust-less steel. I am no blacksmith but, the big thing that make carbon steel stainless steel is the addition of chromium (as in chrome plating). It makes the steel less reactive but the chromium content can vary. The more chromium, the less reactive it is.

The rust on the brushed portion could easily be due to contamination from regular steel if it was brushed with a steel wire wheel. I can't tell what the rust is coming from on the thicker component in your picture. Is that area painted?

I just purchased a one year old Duetto this weekend. When I got it home, it looked like the previous owner had never cleaned the thing (well, they certainly had not cleaned the shower screen, YUCK!)

Once I took the lid off, it looked as though they had splashed water all over the thing inside. There was surface rust all over the place on the case (but not the frame), oxidation all over the steam boiler, and the steam and hot water valves were corroded.

The exterior was fine, so I spent about 5 hours cleaning the thing top to bottom. I took off the "skin" and disassembled it, and used Barkeeper's friend and liberal elbow grease to clean up the surface rust where I could. It cleaned up really well, and then I dried it and hit it with an application of Tuf-Glide that I keep around for firearms.

To be fair to the previous owner, it is pretty easy to splash water around when trying to fill the reservoir (even with a funnel), so I plan on just being vigilant about cleaning up spills. Only one small portion of the rust was anything but superficial surface rust, so I'm not too worried about this thing rusting out from underneath me.