Can I use water heater exhaust pipe for a wood stove?

The Kni-Co wood stoves use a single layer galvanized exhaust that has to be burnt in. The galvanizing burns off, so you have to do it outdoors the first time. I want to reduce the 4" hole to 3", and use double wall water heater exhaust. It is only rated at 400 degrees, but I assume that is to protect the galvanizing. Can I get the permies forum seal of approval on this?

Hi Greg, what's your reason for going with double wall? You'll lose a lot of radiant heat, especially in the first 6' of pipe.

If it's just to protect a tent wall, perhaps an oversized double wall could be a sleeve that provides a heat shield for your single-wall pipe as it goes through.

I'm also worried that there will be slow offgassing from the double wall pipe. Unless you hit it with a propane torch, it might not be easy to fully offgass the zinc with just the stove heat.

This all hinges on where you plan to install this. Can you give us a bit more info?

(Aside: I just picked up a Camp Chef Alpine Heavy Duty Cylinder Stove for my tarp sheds and small shelters. Haven't unboxed it yet. I'm looking forward messing around with chimney experiments too!)

Douglas Alpenstock wrote:Hi Greg, what's your reason for going with double wall? You'll lose a lot of radiant heat, especially in the first 6' of pipe.

If it's just to protect a tent wall, perhaps an oversized double wall could be a sleeve that provides a heat shield for your single-wall pipe as it goes through.

I'm also worried that there will be slow offgassing from the double wall pipe. Unless you hit it with a propane torch, it might not be easy to fully offgass the zinc with just the stove heat.

This all hinges on where you plan to install this. Can you give us a bit more info?

(Aside: I just picked up a Camp Chef Alpine Heavy Duty Cylinder Stove for my tarp sheds and small shelters. Haven't unboxed it yet. I'm looking forward messing around with chimney experiments too!)

I didn't consider the radiant heat. I was just seeing that wood stove pipes are ridiculous priced, and seeing how kni-co uses galvanized...I thought why not. It is for a hot tent made for stoves.

Wood stove pipe can be pricey, but it's generally heavier and lasts a long, long time. There are also different grades (and costs) based on thickness -- thinner stuff used for utility stoves and very heavy stuff used for permanent installations in buildings.

Personally, I'm leery of using galvanized piping with a wood stove, since most of it is really thin and could fail during an overheat (say, in the event a stove door was left open). Maybe that is less of a concern with a tent sized stove.

It is my understanding that hot galvanized metal can give off toxic fumes.   You may want to check into that possibility.

John F Dean wrote:It is my understanding that hot galvanized metal can give off toxic fumes.   You may want to check into that possibility.

It's for a tent, and it is known to do a burn in outside.