Sunday, June 29, 2014

The Replacement Forge Flue


The current coal forge flue and accelerator sections have been used since January 1999 - over 14 years.  It is deteriorating and may fail soon. From time to time sheets of rust fall off the inside surfaces onto the ash pile in the smoke collector.

I made the original flue from 18 or 20 gauge sheet and MIG welded all the seams.  I don’t have the time to do that again so I’m asking Kan FAB to cut and bend 16 gauge panels which will bolt together to form the flue.

This will be an experimental design. The smoke chamber was replaced several years ago with bolt-together 10 gauge panels and angle. That design has worked very well. http://persimmonforge.blogspot.com/2012/05/my-side-draft-forge.html

I designed the new flue panels so they can be assembled from the bottom, where they attach to the smoke collector, upward to terminate in a Vacu-Stack chimney topper. There will be five sections; the smoke accelerator, three rectangular duct sections and the adaptor section to mount the Vacu-Stack topper.  Angle tabs will be welded to provide linkage between the sections.  I plan to seal any gaps with silicone caulk
I haven’t decided whether to make the flue sections with four separate sides or with two-side units which would require just half the seam sealing but double the weight of the panels.  Another alternative  would be to form the back and sides as one piece and just bolt on the front.

Also, I haven't made a final decision about incorporating a damper.  With the ability to remove individual panels that could be added later.


The way this year is working out I will not get this job done until it is cooler and drier in the fall.  I plan to borrow a scaffold  from a chimney sweep friend and set it up outside the shop.
10 gauge and angle smoke collector.

Five-section replacement flue.

Vertical flange and angle-tap joinery.

Smoke accelerator

Vacu-Stack mounting section

1 comment:

  1. Wow! What an amazing design you got there. You really covered all your bases with the design. I think adding the damper will be fine. Anyway, I hope the construction of the new flue for your forge will go well. Thanks for sharing! All the best!

    Rosemary Bailey @ WABI

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