[Amps] Forms for air wound coils

[Roger (K8RI)]

On 7/23/2012 4:38 PM, Gudguyham at aol.com wrote:
> 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

You didn't say how you are going to use this so I don't know what temps 
will be involved.  There are many every day items that can be used, but 
some, or many do not handle elevated temperatures well.

Carpet rolls come in many sizes, I don't know if any are that small 
though. Then just go into a big box store and look for plastic handles, 
rollers,or even toilet paper roll centers.  They are flimsy, but given a 
good coat of shellac they become rigid.  Another thought is plastic 
drain pipe for sinks.

I built an 8" Newtonian telescope out of a 10" carpet tube and *LOTs* 
of shellac (bout 10 coats), so just look for any thing round about the 
right size and that is an insulator.

73

Roger (K8RI)

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