RE: coil forms

Charlie also sells 2", 2.5", 3", and 4" HDPE mortar tubes.  These sizes are 
capped on one end by the forming process, ie. the cap is HDPE.  On the sizes 
5" and above, I believe the caps are wood, so you would want to get them 
uncapped and add your own.

They work great for shells; don't know how well they would work for coils.

Bryan Zublin