Spool holder RepRap Tricolor Mendel 3

Copper pipe supported by 2 of these things makes a holder for 3 spools of filament.
Holder fits the 2 top rails with the option of securing in place with nuts and bolts, or cable ties, or not.
Larger spool needs a center hub to adapt to the size of the copper pipe.
OR, better still, use http://www.thingiverse.com/thing:735213 for the spool adapter.