After descaling, the inside of my 1970s era Oly Club boiler is the color of Georgia red clay, while the outside is a silverish yellow. Are there two different brass alloys here? Is this a yellow brass boiler lined with red brass?

Regards
Timo

Although I'm no expert, I doubt they fused two alloys when building the tank. Instead I would guess that leaching either from the metal to the water or water to the metal has caused the internal surface of the boiler to change color.

The color says Copper........? Perhaps?

'Q' wrote:Although I'm no expert, I doubt they fused two alloys when building the tank. Instead I would guess that leaching either from the metal to the water or water to the metal has caused the internal surface of the boiler to change color.

My neighbor, who is pretty experienced with metals, agrees with you. He says the zinc has probably leached out over the years. See selective leaching.

Regards
Timo

mogogear wrote:The color says Copper........? Perhaps?

I was hoping the interior was copper plated, but I gather not. Haven't heard back from the company that does FDA nickel plating.

Regards
Timo

timo888 wrote:I was hoping the interior was copper plated, but I gather not. Haven't heard back from the company that does FDA nickel plating.

Regards
Timo

Hi Tim,
What has happened is that you have "pickled" the surface with the cleaner. That removes all the elements other than copper from the surface. During smithing of copper, bronze, and brass; that is the usual effect after annealing when the fire scale is removed by acid etching. But, that is not the only process which does that.
That pure copper surface is only a few molecules thick.
richard

Good news Tim- Plating is usually only a few molecules thick- you now have a copper plated boiler -! a patina will form quickly and all will be fine

I am considering gold plate on top of a nickel substrate

espressme wrote: What has happened is that you have "pickled" the surface with the cleaner. That removes all the elements other than copper from the surface. During smithing of copper, bronze, and brass; that is the usual effect after annealing when the fire scale is removed by acid etching. But, that is not the only process which does that.
That pure copper surface is only a few molecules thick.

What is that whitish-gray powdery coating that keeps appearing?

Regards
Timo

timo888 wrote:What is that whitish-gray powdery coating that keeps appearing?

Regards
Timo

Hi Tim,
IIRC
Most often, I would believe, that residue would be a tin/zinc oxide ( depends upon the material spec.) And it takes a couple of applications of scrubbing wih Cafix®, Cafiza® or a similar ( Trisodium phosphate,) no foam, custom coffee cleaner to stop the process.

Chemically, the "base" ( alkali ) of the cleaner neutralizes the acidic metallic / acid compound residue from the use of the pickle/acid cleaner. In a washing machine you do the opposite and add a mild acid (white vinegar works)to remove/neitralize the alkali of the detergent during the second rinse cycle. Cheaper than fabric softener.

Hope that helps!
sincerely
richard
PS. Other opinions requested!

PPS What is now sold as TSP® is not! They ( present conglomerate ) copyrighted the chemical name and substituted a detergent. If you read the box, It says "No Phosphates!" Some paint stores have the real thing.