Addressing Lead in pre-2014/2004 espresso machines

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#1: Post by baldheadracing »

A well-balanced article, I think: Get the lead out - by Michael Teahan for SCA's Coffee Technician Guild blog

Reminder that rpavlis (R.I.P.) recommended:
1. removing the surface lead from clean brass surfaces;
2. then coating the cleaned brass/copper surfaces with a phosphate layer.
His easy-to-follow procedures to do the above are in post #10 here

Note that the phosphate layer is needed with "rpavlis water" as his water will not form the calcium (scale) layer that traditionally built-up and blocked the lead in brass boilers, fitings, etc., from leaching into water.

(For the dates: 2004 was when regulations in the EC were extended to espresso machines (more-or-less). 2014 was when the regulations were toughened so that both the base material (e.g., brass) and the coating (e.g., Nickel, T.E.A.) had to meet regs (more-or-less), and there also had to be a paper trail. This prompted a switch to stainless steel, as SS is less expensive, but SS can have its own issues.)
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada
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baldheadracing (original poster)
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#2: Post by baldheadracing (original poster) »

Sources for the chemicals rpavlis uses:

For "cleaning" the lead off of a brass surface:
Two parts: White vinegar - any grocery store. Don't get any fancy vinegar, get the one that usually the least expensive
One part: 3% Hydrogen Peroxide - any pharmacy/drug store

For the phosphates:
Sodium phosphate - any pharmacy/drug store. It is sold under the brand name "Fleet Saline Enema" but any Sodium Phosphate enema will do. You can also get Sodium phosphate powder off of Amazon, etc., but do you need a pound? A single Enema has about 30g of Sodium Phosphate; that's enough for about 3/4 US gallon of solution.
Potassium phosphate - amazon

Bicarbs for water:
Sodium Bicarbonate - baking soda, (not baking powder). Any grocery store, but doesn't taste as good as potassium bicarb to me.
Potassium Bicarbonate - Amazon or brewer's supply. LD Carlson brand comes in 1lb for $9 or 2oz for $5. Two ounces is good enough for about 100 US gallons.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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#3: Post by baldheadracing (original poster) »

It was time to clean this portafilter, so I decided to try the rpavlis' phosphate coating procedure. Here's the test subject, from a 1985 Elektra Micro Casa a Leva. I don't use this portafilter very much; it's seen maybe 25 shots in the past year.

I cleaned the portafilter with Cafiza in an ultrasonic bath. That's normally good enough but I also did some scrubbing with Bartender's Friend (Oxalic acid).

There was still some cupric oxide left on the surface so I did a quick 10-minute dip in citric acid. Normally this would be bad:
rpavlis wrote:Take care NOT to allow strongly acidic things to be in contact with brass or copper things.
... but the portafilter is going to be in acid in the next step anyway.

Solution preparation. First the phosphate solution:
rpavlis wrote:I normally put a gram or so of one of the potassium or sodium phosphates into about 100 mL of water,
I need 300ml of solution, so about 3g of phosphates. The enema has 27g of sodium phosphates in 118ml solution. I used 13ml enema with 287ml distilled water.

Second, the acid solution:
rpavlis wrote:White vinegar is typically somewhat over 1.0 M acetic acid, usually about 5 to 6%. Mixing vinegar and 3% hydrogen peroxide at a ratio of 2 parts vinegar to 1 part 3% hydrogen peroxide works well.
... so that's 200ml of vinegar and 100ml of hydrogen peroxide. Note that when the vinegar and hydrogen peroxide combine, they form a solution of vinegar, hydrogen peroxide, and peracetic acid. Peracetic acid is highly corrosive and should be used in a well-ventilated area (you don't want to inhale peracetic acid fumes).

After a couple minutes in the solution, some green stuff formed.

A quick stir and the green was gone. Note all the small bubbles forming on the surface of the portafilter.

After a rinse, it doesn't look like the acid dip did much:

However, the acid did remove metal. Note the colour of the acid solution. (The portafilter is in the phosphate solution.)

Done! Note that the portafilter is no longer a brass colour. It is more golden in shade. I've seen the same colour in Soviet-era military medals.

All back together and ready to use.
rpavlis wrote:Do NOT dry the surfaces that will touch food or drink with anything that is abrasive, even polishing compounds after these treatments. Most metal phosphates are extremely insoluble and tend to coat the brass surface and protect it from external things.

Colour comparison: Coated with phosphate vs. cupric oxide (black) patina. (Both protect brass and copper.) I'm not sure what my phone was doing, but the ferrule on the portafilter is the right shade of the phosphate-coated brass. On the Penny bottomless portafilter, the lug and the handle bit are the usual colour of brass. Thus, I'm not sure if I would do this procedure on brass on the outside of a machine, but I will start doing this procedure on the internals of my older machines.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada