Queen Excluder and New Foundation
I attended Brushy Mountain Bee Farm's webinar on honey extraction last night and a response to a question gave me a tip that I thought I'd pass on and put out to you guys for validation.
The host said that you should refrain from putting on the queen excluder until the girls have built out the comb on the super's new foundation.
That may well explain why my super has sat there completely untouched all summer! I made all kinds of excuses for it: They didn't like foundation because I had left it outside in an unused super for too long. They didn't like the foundation because before I put it in the hive I found a giant gross cockroach climbing on it. The queen excluder now seems more likely a cause than them not liking cockroach residue. :)
Anyway I'm new and I hadn't heard that before.