Here is the repaired frame after the JB Weld work. I took it to the powder coater like this:
I put a new bike into service while I had the torque plates at the powder coater. I limited the current in the CA to 25A, but I would get surges of up to 45A, and at one point sent 81A to the motor for a few seconds. What is more, I had failed to keep the axle nuts tight. This resulted in cracking the dropouts on both sides of one frame. It is very stupid to use a Cromotor with no torque plates.
I bought direct replacement dropouts from Paragon Machine Works, and the frame repair shop will either rebuild the damaged dropouts with TIG stainless or weld in the new dropouts.
My electronics tech advised me to not use the regen until the torque plates were on there, but I used the regen anyway, telling myself that I would keep the axle nuts tight. I lazily postponed tightening them, using the strong regen a lot. The axle finally came off a little and the motor wiring harness was damaged.
I am past this disaster now. To recap, I solved the problem as follows:
(1) strip the bike down to the bare frame,
(2) TIG stainless welding repair,
(3) Refile vertical dropouts to tightly fit the larger Cromotor axle,
(4) Fill in all irregularities with JB Weld and sand it down to a smooth finish,
(5) Powder coat the frame again, and
(6) Reassemble the bike, making sure to use torque plates at all times and always keep the torque plate nuts and bolts and axle nuts tight.
Here are the dropouts after I filed them to a tight fit for the large Cromotor axle.
The powder coater did a great job. The JB Weld bubbled up a little in some places.
I found an experienced bicycle frame welder to do the TIG Stainless repair of the cracked dropouts. He decided to weld the derailleur hanger to the frame. He used Argon gas, a tungsten electrode and stainless rod. It cost $180.