Food grade copper joining method

Was curious how to join two peices of copper or brass to where you could use it to heat (180c) and drink from. Similar to a coffee maker.

Wouldn’t silver solder work, similar to copper water pipes? If it’s safe enough for water should be good enough for hot drinks.

We use to make aircraft hot water tanks in house at global engineering they had a stainless steel tank a electric heat pad a fireproof insulation wrap and another metal tank on outside.
We used a silver solder on outside tank but not on the tank that you drink from we tig welded that one

I’ve watched too many plumbers fixing potable water lines, The roll of solder was common acid core solder. Since this device is staying on earth, does it need the engineering spec for the low pressure at 30+ K altitude?

Would a lead free solder work, just as well? 180° C is not that hot compared to 300° C to melt solder.

John

I was always told that you have to be careful when making distillation systems because sometimes you can leach lead from the system into the product. That’s why sometimes the light the moonshine to show you that it doesn’t have a lead content.

This is going tward a coffee brewing system, and on another thread there was discussion about particulars about welding materials, so I thought I’d ping my the community to see what the best way to make a hot copper cup of as kava was.

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The majority of commercial coffee brewing systems I have worked on or looked at that have any copper or brass use brass ferule compression fittings at the ends of copper tubing in the heated water path, but occasionally brazed connections for vent and overflow lines that are not in the potable water path. I have also seen hard, lead free solder used, but those are always the source of corrosion issues. Almost all modern machines use no copper or brass and use plastic and stainless steel instead.

Mike

Dissimilar metals?

I could do it all in one metal. I considered doing it all one piece initially

Yep. Copper vs yellow brass is tiny electrochemical difference. Copper vs tin, or zinc is bad. It’s a mistake to treat water as if it is non-conductive, especially hot tap water. Even aside from corrosion and erosion, the dissolved metal salts add undesirable taste to coffee, and I’ve even seen coffee turn violet when powdered creamer was added because of mineral content.

Isn’t water a poor conductor itself it’s the stuff in the water that makes it a conductor i.e. 100% distilled water poor conductor?

Extremely pure water is an extremely good insulator. It’s commonly used in high voltage switch gear as it is superior to even inert gases or a vacuum in arc over properties. But that’s not just ‘distilled’ water, which I’d never use to make coffee anyway. It takes deionizing and degassing to get water sufficiently non-conductive to be a good insulator.

Dihydrogen monoxide is not to be trusted
https://www.dhmo.org/facts.html

So you think compression fittings would work best? And just not do any kind of welding at all? Or is there a safe way to like…

Is tig welding an option ?

Yes. Compression fittings.

I just had a 1997 BUNN 3 burner restaurant maker apart for another reason and there was no visible corrosion of the fittings or the copper line that leads from the heated stainless tank to the head. That machine has probably made 20,000 full cycles and that style maker keeps the water tank heated continuously.

Did you mean 180 degrees Fahrenheit. Or is this for use at 150 psia? 300 foot depth diving chamber?

Mike

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Heat comes from a butane torch…

If you use compression fittings make sure you use copper olives, the plastic ones don’t hold up well under high temps.