Electric Wall Heater Repair

[jakeru]

I did a quick welding repair job today on an old electric wall heater that had a damaged heat exchanger, which was obsolete (no longer available.) The ~50 year old heat exchanger became bent (not shown) due to excessive heating (from previously replaced components in the heater, such as the fan motor) and customer had cold straightened, leaving some cracks in the aluminum alloy I quickly and partially TIG welded (crack repair not shown.)

Curiously, the heat exchanger mounting brackets were also about 1/4" too tight, so I repositioned one of them by cutting it off from the rest of the sheetmetal frame (4.5" angle grinder w/ cut-off wheel) and re-welded the bracket back on to the frame in a new position. Resulting in the heat exchanger able to be installed without stress.

As the bracket / frame was pretty thin sheet steel (I didn't measure but would guess perhaps .050" or so), I used some aggressive pulse settings (minimum pulse background current, and minimum pulse duty cycle, and minimum pulse frequency) to minimize heat input and oxidation, while welding it up in one quick pass. I used 1/16" 309L stainless filler rod, a #6 gas lens with ~13 cfh argon, and a really sharp 1/16" tungsten electrode.