Schrader stove starter collar

I'm trying to vent an older Schrader stove and the starter collar is an odd size, I measured 7 5/8". The 8" stove pipe is not a good fit and crimpiing it doesn't help either. I replaced all of the original single wall pipe that the customer had put in originally (he had a chimney fire) and used double wall DuraVent 8" going from the top of the stove to the ceiling support box. The rest of the way up I used 2100 degree pipe. I tried an adapter that DuraVent makes a double wall that's 7 1/2" (inside at bottom) X 9" (outside at top) but still I'm still having the same issue.The height of the venting is more than the mininum height and runs all the way above the peak of the roof, but we're getting a down draft (only when raining) and theres a leak at the starter collar. Does anyone manufacture pipe for this stove anymore? I think the best option is to replace it (the stove)due to the lack of efficency, but the customer wants to keep it. Any help would be appreciated.

webbie said:

I have actually been able to crimp to fit them - but it's not done in the standard way.

You have to use 24 ga (not 22) stove pipe and go around it a couple of times to really make it smaller. Then, once it's really crimped, you go around and bend it somewhat straight (when you crimp it hard it will be like a cone on the end, so you want to make the lower edges straighter - lining up with the regular pipe, but in a smaller diameter. Then use furnace cement as well as a screw or two.

Click to expand...

Are you using single wall pipe when doing this? We need to use double wall pipe due to clearance issues and the outer pipe covers the collar so I have no way to use furnace cement. I did try to put furnace cement (to cover the gap) from the inside of the stove, it fell out after some time. I thought about trying some self adheasive window gasket around the crimp. Thanks for your help.