[Amps] Forms for air wound coils

[Gudguyham at aol.com]

Other than ceramic, can anything else be used as a coil form?   Heathkit 
used a fiberglass form in the SB-220.  At least I think it was  fiberglass.  
Seems to have worked OK.  Dentron used what looks to be  some type of 
phenolic material.  Not really sure what it was.   Anything out there that can be 
used that does not cost an arm and a leg?  I  am looking to make a coil for 
RF about 1 1/2" to 1 3/4" dia about 6" long. Not  to be used for plate 
chokes. Lou