Heat Exchanger

[DirtyHarry]

Anyone have detailed beta on constructing a heat exchanger out of copper tubing or whatever for a canister stove. I know there were some threads about this before at some point, but I can't seem to find them.

[Dru]

buy some thick copper wire

pound it flat with a hammer

wrapit tightly around the canister about 5 times and have the end flare over so it sits in the burner. It should look like a big ol' cobra wrapped around the stove and ready to strike the burner. if its not wrapped tightly it will slide off the canister*.

 

don't wrap it underneath or your heat exchanger will burn a hole in your stove board. maybe it's OK in a hangoing stove.

 

the wraps make it hard to grab your stove until it cools down.

 

for less efficiency (full cannister) use less wraps

for more efficiency (almost empty cannister) use more wraps

 

practice in backyard so your exchanger doesnt blow up your stove leaving you stoveles halfway up the Nordwand of der Gross Shmeeb.

 

* you can put a wrap around one or two of the pot rests on the burner, just below the cobra head part, to stop the slide off effect

[DirtyHarry]

Thanks. Sounds simple enough.

[Dru]

 

Imagine the snake is coiled around your canister and the burner is under its chin. And imagine the tail isn't sticking out like that either. Just cut the tail off flush with the canister.

[fishstick]

A simpler method...

 

Buy copper tubing that is roughly 3/8 of an inch in diameter.

 

Cut to length. Sounds obvious, but in this case length depends up cartridge SIZE and stove model. See more below.

 

I pounded one set of exchangers with a hammer, but found squeezing the tubing in a vice did a much better job.

 

I used 3 L shaped exchangers per cartridge (on a bluet turbo 270).

 

I had an old OR water bottle parka sitting around, which made a superb insulator for the BIG bluet cartriges. I cut the parka in half along the zipper line, then split most of the stitching holding the end cap in place such that it would flap open. The parka is used INSIDE OUT, and the flapping end (can be closed with velcro is used hanging)(I just buried mine in the snow for stability) offers the ability to preheat the bottom of the cartridge directly with a lighter.

 

Simply slide the L shaped copper exchangers between the insulated parka and the cartridge at roughly equal distances. They should be as deep as the cartridge used, and stick almost to the center of the burner head. Avoid putting an exchanger near the control knob.

 

The entire system can be put together while wearing mitts.

The exchangers will turn the outer fabric of the OR water bottle parka slightly brown, but won't melt it or the foam.

 

The remaining half parka will work (not quite as well) for the smaller Bluet cartridges (extra (shorter) exchangers are needed).

 

An average meal will generate enough extra warmth that the cartridge is still warm to the touch 25 minutes after turning the stove off (in the CDN rockies). Still, I used it at temps around +3C and nothing blew.

 

I'm unsure if other cartridges will work with the OR parka.

 

GB

[Dru]

http://www.psychovertical.com/?lowtemptips

 

Andy Kirkpatrick tips

 

Just duct taping a shake n heat hand warmer to the cartridge base has worked quite well for me in the past.

[chris]

Does anyone have pictures of their set-up? For all the countless times I've read about this, I've never seen a photo of it. I'd like to see if what I've rigged is similar...

[jhamaker]

Tried it w/ wire - the heat never got as far as the canister on my Bluet. I had better luck digging a slot in the snow and sticking a candle under the canister.

[snugtop]

Here's a safer method than Dru's (if you have an extra lid or pot)--

 

If you can get it started, put a quarter inch of water in the bottom of one pot, or the lid of your pot. Heat that water up then put the canister in it.

 

You have to change the water every once in a while but it turns your stove into a blowtorch.