metal underneath pickups?

[jim primate]

i know some fenders came with brass plates underneath the pickups to help with shielding.

but what about a metal that'd react with the magnets. like steel or iron.

would this affect the sound any?

i've read that some pickups with non magnetic pole pieces have a magnet and piece of iron or steel on the bottom of the pickup.

can someone enlighten me into some pickup theory?

[A9X]

The pole pieces would need to be magnetic.

Steel below the pickup may have an effect, depending on the design of the pickup.
Why do you want to do this? Copper or brass sheeting is cheap, light and solders well.

[Searcy]

http://www.tdpri.com/resourceBASEPLATE.htm