wigglywalker

There is a place in NH that is using an old water boiler, he has a 30~40' 2" copper coil? on a 250 gallon still. i am sure if you have a larger still steam would start to make more sense? seems to work for him, he also has a frankinstien hot water heater connected to it, not sure if it is to superheat or a buffer tank? i do understand that to change phases from water to steam requires 970 BTUs per lb. so it is kind of a waste of energy if you don't need it? i am sure heat up time is a factor, but as i type this i am trying to think how to pipe our new steam boiler...

I am not tiring to sound rude when I say this.

Joining copper to stainless is hard to put together if you a novice welder. But for someone that is a really great tig welder they should be able to do it. Even if that person has never done that weld before it is easy to learn.

depending on the process you can use :

1. 316l ss filler

2. 312l ss filler

3. regular copper ele wire (but it contains oxygen) not the top choice

4. Di-oxidized copper tig filler (super good, plus can be ground to make the pieces look like one)

5. not a welding process but you can use the tig welder / silicon-bronze ( a very ductile joint) very go

While searching to see which filler to use i came across a post on some other site saying to watch out for different expansion rates of metals (copper/stainless) the issue was with the welds cracking at heat up/cool down. they recommended using silicon bronze vrs the parent metals. i think the site was something to do with NASA so i am sure the temperatures are not near what we are dealing with but I switched to silicon bronze after reading that when joining copper/stainless.

Copper sheet thickness.