La Pavoni Europiccola boiler red rot

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Yotam

Postby Yotam » Jul 03, 2019, 1:03 pm

So... The other day I got around to descaling my recently acquired 76' Europiccola, there was a good amount of scale, but i've seen much worse in these forums. The water that came out were all blue, and I noticed that there was a little brown spot on the outside of the boiler, with the chrome peeling off. So I took the HE off again to inspect, and sure enough there was a red spot on the inside. From what I understood from this post and this post from the late Dr. Plavis' explanations is that hard water with chloride were used in this machine; furthermore he indicated that there wasn't much to do other than polish it out and applying a strong sodium carbonate solution -- I assume just leave in the boiler for a while?

Has anyone had experience with this? Will this get worse, or will the metal stabilize as copper with sodium carbonate and the polishing?

Here is the spot on the outside (I removed the loose metal):
Image

Here is a picture before polishing:

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And here is the area after polishing:

Image

OldNuc

Postby OldNuc » Jul 03, 2019, 1:07 pm

The heating element is either touching the boiler shell or it was bridged with hard scale. The copper will be fine as long as it is not cracked.

Yotam

Postby Yotam » replying to OldNuc » Jul 03, 2019, 1:38 pm

Thank you! You've put my mind at ease. There are no cracks, and I touched up the outside spot with some high temp silver paint.

The boiler is not touching the side now, I checked the clearance with a bamboo skewer. Perhaps it was before because someone used a rubber gasket for the HE that was thinner than the thick flat one -- so the HE was at a different position. I wouldn't rule out scale as there were some spots with a thick buildup.

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drgary
Team HB

Postby drgary » Jul 05, 2019, 2:54 pm

It looks like you may have a pinhole in the boiler -- hard to tell by your photo. There's a type of sealant that wicks into the pinhole and seals it, Loctite 290.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

Yotam

Postby Yotam » replying to drgary » Jul 13, 2019, 11:26 am

I've double checked, there's no pinhole, the brass got dezinced and there's a patch of copper there now. On the outside of the boiler some of the copper oxidized (maybe .1 or .2 mm). Other than that it seems fine. Is Loctite 290 food safe? I was leaning towards silver soldering if there was ever a problem with it.

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drgary
Team HB

Postby drgary » Jul 13, 2019, 11:46 am

It is NSF / ANSI 61 certified. As I understand it this relates to its being used with potable water and storage of chemicals that are outside our interest here. The bottle shows it can be a skin and eye irritant, so I wouldn't leave a dot on my hand after applying it. When I've used it, it plugged tiny pinholes and dried, and I believe the NSF/ANSI certification relates to it not leaching into potable water within its temperature range.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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Paul_Pratt

Postby Paul_Pratt » Jul 14, 2019, 6:11 am

I would not risk silver solder on that unless you plan on rechroming the boiler. A soft lead-free solder can be used and you should be able to use it without ruining the chrome. I think there is something there that needs attention.

Yotam

Postby Yotam » Jul 14, 2019, 12:38 pm

drgary wrote:It is NSF / ANSI 61 certified. As I understand it this relates to its being used with potable water and storage of chemicals that are outside our interest here. The bottle shows it can be a skin and eye irritant, so I wouldn't leave a dot on my hand after applying it. When I've used it, it plugged tiny pinholes and dried, and I believe the NSF/ANSI certification relates to it not leaching into potable water within its temperature range.


I got the boiler up to pressure and sprayed water around the that area, no leaks, no steam. The copper seems to be solid. I will keep the loctite method in mind if any issues would arise. For larger holes, would you ever consider using an epoxy putty:
https://www.permatex.com/products/adhesives-sealants/epoxies/permatex-steel-weld/

Paul_Pratt wrote:I would not risk silver solder on that unless you plan on rechroming the boiler. A soft lead-free solder can be used and you should be able to use it without ruining the chrome. I think there is something there that needs attention.


I tapped the copper, it is very solid. Other than drilling out that whole spot (about 3-4 mm in diameter), performing high temperature bronze brazing, or soldering a small brass plate on the inside of the boiler -- I don't see any solution to that copper spot. Having said that, the metal is very solid, and I don't see a reason to touch it. From what I understand copper is softer than brass, but as long as it holds I don't want to do anything to make a problem where there isn't really one... like OldNuc said, if there is no crack in the metal not to worry about it. Would you suggest removing the copper sooner rather than later?

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drgary
Team HB

Postby drgary » Jul 14, 2019, 12:48 pm

Yotam wrote:For larger holes, would you ever consider using an epoxy putty:
https://www.permatex.com/products/adhesives-sealants/epoxies/permatex-steel-weld/


I don't know about that Permatex product. For a larger hole in a pressure vessel, I would hesitate to do anything other than a proper metal fix, such as the one that Paul Pratt suggests. This may get theoretical compared to your issue. There are some boilers that are getting lots of pinholes, which indicates that the entire boiler wall may be degrading, so it's time to replace.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

OldNuc

Postby OldNuc » Jul 14, 2019, 5:35 pm

A pinhole in a pressure boundary can be repaired by many means. The actual pressure in pounds/sq in is minuscule with a pinhole. Brass takes on a copper color if overheated but it is not markedly weakened or destroyed. as ther are no physical signs of a actual leak then it is a cosmetic defect in the chrome. Most likely that is a copper and not brass shell. As to repairing the coper spot StayBrite 96/4 would be my choice and that is going to require heat at 431F which can be destructive to surrounding chrome, best to leave it alone as spot heating copper is a real challenge.

These things do get eaten up from aggressive chemical cleaning and/or water quality issues.
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