I've been using scrap pieces of PVC trim on my bucket, roughly 1x4" size. cut a 45 degree bevel on the front edge, and countersink the four holes for carriage bolts. It's not the most durable material but they were scrap pieces from a shed I tore down. I went through two edges this winter but they were free, and the second one could get a few more storms in if needed.
For next year I plan to get an 8ft piece of Trex decking and do the same with that. Should be a lot more durable than PVC trim and I'll have two cutting edges for $16.