Fisher catalyst mod

[albert_k]

Hi gang!
i’ve got a Baby Bear in a Northern Minnesota cabin that’s about 320 ft.² and not terribly well insulated. As you expect, I struggle from burn times at night in this little stove. While installing the baffle upgrade last week, I came up with an idea for a removable catalyst, and I thought I would throw it by you. currently the baffle plate goes from below the rear exit, Slanted upward toward the rear upper joggle in the middle top plate. This allows the necessary 2+ inches of air gap for me. However, as I was thinking about it, I could cut a round hole in that plate toward the front of it and install a round catalyst. I can then install a second smaller plate (about 13” wide by 3” deep in front of it that acts as a bypass when tilted up, and closes of the 2” exhaust gap when down, forcing the exhaust through the catalyst when operated. The only exterior modification I would think I would have to do would be to drill a hole in the side of the stove, right where the low deck joggles to the high deck. install a small but heavy duty steel tube with a joggle bend on the inside to raise and lower the bypass plate when rotated. this tube would protrude a couple of inches out of the stove and have a handle.. the end of the tube sticking outside of the stove would be threaded and have a slot cut in it. A threaded knob would then be installed in the end of the tube. Similar to the front air inlet, as you unscrew the knob, more air gets into the catalyst. thoughts?

 

[MongoMongoson]

If you are looking for a metal working project and enjoy experimentation, then I say go for it. Any hole you put in the steel body can be filled if it doesn't work out. It sounds like something that will take some experimentation and fiddling. If that is what you are after, you can stop reading right here and just get to work.

Otherwise, I have other suggestions.

I would think you should be able to roast yourself out of the place with a baby bear if it is only 320 sq ft. I know the stove is small but even so, the space you are heating is tiny... before you go to bed, do you have a nice coal bed established?

If you don't want to do the old smolder/creosote factory with your old style stove, one thing you can do is to get a nice big pile of coals built up and have those carry you through the night. You might need to have the windows open while you are building your coal bed by feeding in lots of hardwood as your flames burns down and you want to make more coals. What are you burning? I burn popple for quick max BTU output without coal overload, but sugar maple and ironwood to build overnight coals.

With such a small space, it will be difficult to get a stove (new or old) with a firebox big enough to carry you through the night that is not so big that it turns the place into a sauna while you are feeding it. Consider sealing the place up and insulating it rather than trying to modify your stove.

My place in the UP isn't much different than yours. I have 400 sq ft and use an old Quaker Buck to heat it. I have the advantage with that stove of having a deep firebox where I can build coals in the back and pull them forward before bed to have them burn through the night. Even so, it can be cold in the morning with just the wood stove burning.

I did not add insulation, but I did seal everything up inside and outside around the windows, doors, and ceiling to try to keep mice out. What a difference that made! I used Great Stuff with hardware cloth for big gaps and caulk for smaller ones. My main goal was to keep mice out (thus the hardware cloth), but while I was there with a caulk gun ready I sealed up any gap I could. It worked. Not one mouse for the last 3+ years. After I did it, I noticed the benefit of holding more heat overnight .