Copper water coils - Why not ??

I have water coils in my stove made out of stainless steel.

My question is, why aren't they made out of copper? Copper can be bent with minimum kinks, if water is constantly running through it, the piping shouldn't get hot enough to even set off a pressure relief valve?

So I'm just wondering why I never hear/read of people using copper water coils inside of coal stoves?

Any takers?

Because they'd melt the second water stopped flowing through them, would be my guess.

Even if it won't melt because its full of water moving all the time and pulling out the heat, it would work harden over time and crack quite easily. Malleable metals don't have a big tolerance for high temps.

I made a copper coil for my ulefos wood stove years ago, even the return bends were soldered with 95/5.I used it for DHW in a 40 gals stone lined storage tank right behind the stove.I used it for 9 years and it looked like new when I took it out.
BTW it was a gravity system,no circulators.
DON

BIG BEAM wrote:I used it for 9 years and it looked like new when I took it out.

LOL...Made fools out of us, eh Coaledsweat?!?

It will work in a wood stove but with coal the nitric and sulphuric acid in the flue gases and fly ash respectively will eat copper within a very short time. Just like people that have acidic potable water usually have problems with there copperpipes developing pin holes over time but the heat accelerates the process.

And this coil was about 6" above the top of the wood when loaded.It made LOTS of HW.The top of the tank was 190F and the return water( bottom of the tank would cool to 150F ish.Tank had no insul I thought heat lost in the house was not lost.I used a tankless coil in the boiler in the summer.
DON

jpen1 wrote:It will work in a wood stove but with coal the nitric and sulphuric acid in the flue gases and fly ash respectively will eat copper within a very short time. Just like people that have acidic potable water usually have problems with there copperpipes developing pin holes over time but the heat accelerates the process.

That may be true with the acids,But most of the pin holes I've seen in copper pipes was because they used M copper tube for water lines.L copper tube is for domestic water and K for under ground.I bet if you could find some thick fittings and used K copper tube it would last a long time.Just a guess.
DON

I'm trying to remember if a thing caller a crows foot was made out of copper or iron pipe.They were used in coal and oil furnaces to make DHW and then you would set up a range boiler(type of storage tank I used on my wood stove set up)for DHW.
This was back in the 20's and 30's.
BTW my grandfather and father were plumbers as I am.And I'm 54 yrs. old
DON

They had to be made of galv pipe because copper wasn't around until 1939 and wasn't widely used until after WW II.Good to get my brain going again.
DON

BIG BEAM wrote:I'm trying to remember if a thing caller a crows foot was made out of copper or iron pipe.They were used in coal and oil furnaces to make DHW and then you would set up a range boiler(type of storage tank I used on my wood stove set up)for DHW.
This was back in the 20's and 30's.
BTW my grandfather and father were plumbers as I am.And I'm 54 yrs. old
DON

IIRC they were cast.

I built a copper coil that I installed in a hand fired stove and actually had the coil buryied in the coal bed. This provided gravity heat in my living room about 5 years until I installed the central furnace. I silver soldered the joints and never had any leaks or problems.

Yeah coaledsweat I think you're right.Thanks
DON

Interesting discussion.

I've soldered many copper pipes and anyone who has done it will tell you that even if there's the slightest bit of water laying in the pipe, the solder will not hold.

Also, solder melts at roughly 300 °F. Water boils at 212°F In short, your pressure relief valves would blow before the soldering failed.

Now the pipe itself, the thicker the better but I have no idea how the acidity would effect the copper.

The idea of burying the coil in the coal, thats an idea.

Keystoker uses copper water coils! But it looks like it is not in direct contact with the flue gas.

http://www.keystoker.com/coaloilboilers.html