[Cob] cob/earth oven also heating hot tub intake?

[KC Chandler]

On Thu, Dec 30, 2004 at 11:28:13AM -0800, Tys Sniffen wrote:
 
> I would like to build a cob baking oven and run copper piping through it,
 
Greeting to the coblist, 
My two cents worth:

Yes, the old woodstoves used steel (thick-walled) pipe (no point in galvanizing, it will burn off, copper is too soft). No, they are not going to explode or have a catastrophic failure inside your stove. 

The old water heaters had a safety valve of course, but, if you're simply circulating through your hottub, then obviously your hottub is a (very large) safety valve.

The pipes were plumbed at the side of the firebox, so were directly in the fire as old wood cookstoves had/have a small firebox.
You may have to replace them every few years, but, when they fail it's usually just a pin hole leak, and your ashes will be damp in the morning. If they're going to fail at a joint, it's probably something in your workmanship and you'll know it early. 

~KC