Since I had no Cafiza on hand, I swabbed the interior of the boiler down with a baking soda solution. Two applications appear to have stopped the oxidation.

Thanks for the explanation, Richard.

Regards
Timo

Now, if the nickel plating on the interior of the boiler is active (i.e. not passivated), and the heating element is copper, and there is no sacrificial anode, then, according to this Chart of the Galvanic Series, it is only a matter of time before the nickel plating inevitably corrodes because copper is nobler than active nickel.

Can nickel plating on the interior of the boiler be passivated (in a food-safe manner) so that it is nobler than the copper element? Or, are sacrificial anodes available pre-fab in a standard BSP or NPT thread appropriate for a 3liter boiler?

EDIT: The answer is yes. E.g. at McMaster:

3606K6
Zinc Corrosion-Inhibiting Rod 1/4" NPT, 3" Rod Length, 3/8" Rod Diameter
In stock at $5.88 Each


Now the question becomes, is this kind of zinc rod appropriate for a potable-water system?

Regards
Timo

Hi Tim,

Hi Richard,
The specific wear-issue I was trying to solve is the deformation of the slot in the fulcrum mount and the wearing thin or even the wearing-through of the brass at that location. The abrasion there is much exacerbated by the thousands of pounds of force applied to the hardened steel pin and then to the brass, via the lever. If Delrin is harder than brass (I think it is), it might make a decent slot liner. I don't know how thin it can get before it looses its strength. Perhaps something like this, but less ovoid and more lozenge-shaped:

Well Tim, brass by its nature does work harden and develops a very hard layer on the surface and to a depth determined by the force ( No, I cant give you a formula! )
Delrin is a good bearing material for a radial bearings or rotational bushing but can be pressure cut. ie. A cut made by displacing the material by extreme unit are pressure. Thats what a knife does. Applies the greatest pressure to the smallest area.
The deformation of the slot is mostly just plain pressure bending of the material, by and after wear has reduced the thickness of the parent material.. Unless a stainless steel insert were placed above the slot there is no way that abuse will not deform it. I can not think of a fastening system to accomplish such a feat. But, that said, I would suppose a hardened 440 series Stainless steel bar could be inserted and J-B wWelded in place in the top of the slot.
I would believe that the lubrication of the pin roller tube would be of immense value. That changes the force from a pressure friction to a rolling pressure and would reduce the scraping of the top of the slot. But, within the slot and supported by the parent material.

Teflon-coating of the piston cylinder is something I would consider; you know the EPA's take on brass in potable water systems.... Wink I have been reading about electroless nickel-teflon coatings, but will look for Magnaplate.

BTW, the company that originally said it would take on the job of replating my boiler has gone incommunicado. Can you recommend another who might have experience with Magnaplate?

Regards
Timo

The materials are applied by select electro-platers around the country.
This is Magnaplate' url
http://www.magnaplate.com/
andhttp://www.magnaplate.com/solutions/certification.html
enjoy!
richard

espressme wrote:

timo888 wrote:Teflon-coating of the piston cylinder is something I would consider; you know the EPA's take on brass in potable water systems.... Wink I have been reading about electroless nickel-teflon coatings, but will look for Magnaplate.

BTW, the company that originally said it would take on the job of replating my boiler has gone incommunicado. Can you recommend another who might have experience with Magnaplate?

The materials are applied by select electro-platers around the country.
This is Magnaplate' url
http://www.magnaplate.com/
andhttp://www.magnaplate.com/solutions/certification.html

Thanks for the certification link.