DIY secondary combustion tubes

I am glad I found this site through google. I am not new to wood burning I have been running a Vermont Castings Encore for years and the stove does a decent job.
I inherited my grandfathers 1979 Daka wood furnace due to unfortunate circumstances. I remember loading it as a kid and it really kept his large, drafty house warm. Overall it is still in decent shape, the inside was just steel and a bit warped from being over fired. I lined the both sides and back with firebrick and a piece of refractory sheet for the top. The ash grate was still in great shape because I think he replaced it a few years back. The bimetallic damper is still functional as well as the rear thermostat and blower. I really like the auto damper feature you just set to low, med, or high and forget about it as it opens and closes itself to what setting it on. The firebox lined is still huge 28x18x17.

my main question does anyone have any links to a DIY secondary combustion tubes or chamber? I have searched the net and this site and I have not found much. I am sure someone has taken their old 70's stove and made it more efficient. I played around with the fire brick set up and I think I can manage to add a catalyst but the burn tubes would be cheaper in the long run. I plan on keeping the Vermont Castings and running this into my AC system and it will do a better job of distributing the heat. Any help, links or advice would be appreciated. Great site!

I found this but it seems too simple?
http://www.youtube.com/watch?v=3YxrP_YHwJk

Do you see any problems with this? I have worked a stove with secondary air tubes but I have never owned one. If it were this easy it would seem like more people would be converting older stoves into more efficient burning stoves. If this will work as it seems to in the video, I will go buy some SS pipe today and metal bits and give it a try. The way the furnace is set up I could put quite a few tubes going from front to back with not much work. Will this work?

Awesome that is what I was looking for! I will combine a little of both ideas. I got off of the phone with someone at vermontironstove.com, they made those videos and they have tried many different variations and they have all worked well. The one I posted the link worked very well he stated but they generally don't do them like that because it detracts from the look of the stove. Here is another picture of another burn tube set up in an ELM stove. Those are unique looking stoves IMO.
look at picture 18
http://benchman.smugmug.com/gallery/8441935_7ZeEF#554806224_djiHD

It worked! I got the unit installed in the basement this weekend and once the tubes engage I see no smoke from the stack. I have no way to see in the box as it has a steel door

I drilled 6 holes in the furnace going from front to rear and tapped 3 SS rods in place. I drilled about 20 small holes in the portion of the rod that was exposed to the firebox. There is no way to control the airflow in the tubes at present, but I will work on this in the spring, if I even have to. I did place another piece of old ceramic refractory on top of the tubes to reflect the heat. In the spring I think I will morter some fire brick to the top of the furnace because the ceramic is pretty old and I do not want to shell out the $$ for a new piece.

I really have to get use to using this furnace vs the Vermont Castings. The furnace will heat the first floor, living, dining, kitchen and entry parlor up to 82 pretty darn quick. I have always relied on the heat radiating and rising to heat the 2nd and third floor but they are cooler now, I guess because of the radiant put out from the VC. My house on the top two floors have a seperate zoned Unico AC system installed so this spring I am going to have to figure out how to get more heat upstairs. I have four chimneys so I might just install the VC on the 2nd floor and get a small aspen for the third?? The 2nd floor was around 68 and the third 63 which is not too bad but the 2nd was usually around 72 with the VC and the third about the same.

All in all it was pretty easy to get an old non efficient stove more efficient. If you have one don't be afraid to modify it! All I did to mine is what he did to his in the youtube link I posted and it cost me about $12 for the mod, not including the morter and firebricks.

I will try and borrow a camera and get pictures but there really is nothing to see...just some tubes going through a balck box