Fischer Mama Bear Question

I think this was a double door model - that would mean 8" pipe

Craig will know more about it but if I remember correctly the Fischers had a goofy flue coller. A six inch pipe fit over it instead of into it so they leaked creosote onto the top of the stove or out on the floor if vented from the back.

Some people crimped a six inch pipe down so it would fit into the collar like all good connection should and pinned them with sheet metal screws.

Hmmm.. Just saw Craig's post. My memory must be shot. I thought the Mama Bear was six inch.

Never mind.

Correct - they used pipe that was too small - you needed to get an adapter or do a super crimp. Old Mill stoves did the same thing - we had a special technique we called the "Old Mill Crimp".

I think Fishers came in both single door and double door versions. Most single doors were 6", while double doors were 8".

Yes, you have to double and triple crimp.

First, you go around (with hand crimpers) and crimp it well...then go around again. The third time go around and slightly angle the crimpers so the crimp tapers inward a bit - to make it smaller. Of course, this is no good yet because a crimped end shaped like a nose cone will tend to slide up and out when it heats...

So,

for the final crimp, go around and break the crimp back so it is somewhat parellel to the rest of the pipe....if you did your job correctly it will be parellel, but smaller.

Use furnace cement and drill a couple holes through the flue collar for sheet metal screws for the best fit and hold.

Harbor Freight has them. So does any place that sells equipment for duct work.


http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93192

Get Malco brand if possible - also, at least 5 blades - the ones with 3 blades are for gutters.

Most Plumbing and Heating supply houses will have them.

http://tinyurl.com/z89xw is one on Amazon.....the pic actually shows the middle stage of that Old Mill Crimp.