In a previous thread http://www.mapletrader.com/community...ead.php?t=4532 I posted my home made brake for bending flues. Now will post the process I followed to make a flue pan. It is not done yet - so this will be a work in process.
I bought a 4x8 sheet of 20 gauge mill finish stainless for my pan, and I wanted to use it to the best advantage. I had a 9" strip sheared off the long edge, leaving me with a 39"x96" and a 9"x96" piece.
The pan is 39" long x 19" wide, with 9" sides and 6@5" flues, 2 in each of 3 sections.
I carefully marked both the top and the bottom side of the sheet at every bend location - some marks are on the top, others on the underside - along both edges of the sheet. I have a sketch somewhere that I will scan later and attach that shows the design.
First - Pictures of the brake (again)
The brake is primarily made of 3x3 angle with a 3" x 1 1/2" channel for the bed so that the flue can slide over it for the next bend. I have 2 hold down bars - one a 3x3 angle which permits overbending, and the other a 3/4"x 2" bar to fit down in the flues. The first shows on 2 of the pictures, the second on the last. Since this picture I modified the 3/4" bar to add a strip of 1"x 1/4" flat bar offset towards the front to provide some stiffening and allow a slight amount of overbend. It helped but was not enough - see below for the solution.