Not a surprise with Crimped-Wire. It just needs to be supported. We were shown how to cross wire it in Bee Class. The pins only hold down the edges. The middle still bows out some. The cross wire does a good job and I plan to use it. It's extra steps I wouldn't need to take if I used all Plasticell. But the bees like the regular wax so much better than the plastic stuff. Also, when it's time to renew the wax comb I can pull it ALL out, clean the frame, & add all new wax foundation. With plastic I can only scrape it off. There would always be some old wax stuck on the foundation. Pluses & minuses either way.
Unsupported Wax Foundation
The Drone comb surprised me. I bought 3 frames and they all had a slight bow to them. As a ridged plastic product it should not have this problem. I could say 'warp' but it bent the same way unsupported wax foundation does; pushed out from the middle. Maybe I got a bad batch maybe not. I added a coat of wax to them so the bees would draw them out faster. With the heat of the melted wax the bow became very pronounced. Practically unusable. After cooling off they returned to their original condition. What little bow remains I might get rid of with a few weights left to sit on top for a week or so. Again extra steps but do-able.
The more I think about it the more I think I have a bad batch. I'll ask around at the club meetings and on the forums.