>I have talked to Nick at Pierco about this.   Apparently there is no
>solution.   It is not a problem caused by inappropriate frame spacing,
>but just an idiosyncrasy of the Pierco frame.  Perhaps any plastic frame?
 
I think I know what's going on here.  I, too, had a super with mixed wood
and Pierco frames.  Only the Pierco frames were getting comb built on the
tops connecting to the super above.  What I realized was, the Pierco
frames when new have a thick layer of beeswax on the _top_ of the frames.
Wood frames, of course, don't have this.  I guess when they coat the
Pierco frames with wax, they just dunk them in a vat of melted beeswax.
 
Now, when I install new Pierco frames, I scrape off any beeswax on the
top, sides, and bottom of the frames.  Sometimes quite a lot comes off.
This has improved things considerably.
 
Mike Killoran                              --------------------
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(617) 981-2667 (Lexington, MA USA)         Prediction is tough.