I got a bucket, heat gun, pipe/ flanges, and clamps.
Basically heat up bucket why it's pivoting on flange and pipe. Then use pipe clamps to draw it out.
Step 1: Bucket Pivoting on Pipe
Attach rope or wire to bucket.
Place larger heat resistant "die" to draw the soft bucket against.
Heat up bucket
Then evenly squeeZe the clamps to draw out the bottom.
Step 2: Finished Bottom
Don't drill a hole and then heat and draw or the hole will stretch and deform.