On Mon, 15 Feb 1999 00:18:09 +0000 "Ian White, G3SEK"
>>On Sun, 14 Feb 1999 11:28:09 +0000 "Ian White, G3SEK"
>>>In the end, the only way to find out is to try it. For situations
>>>an inexpensive and easily machined material such as Delrin is proved
>>>work, there's no point in paying for PTFE or ceramic.
>>B&W initially used ceramic forms for their 802 plate RFC. As a cost
>>reduction they went to Delrin. I have several failed Delrin RFC's
>>that all failed at the tube end only which makes me believe it was a
>>related failure, not DC or straight IR losses.
>Fair enough - anything involving high RF potentials (and probably
>temperatures too) is a risky application that would need careful
>before committing to production. It's more difficult for component
>manufacturers such as B&W and the roller coil makers because they
>anticipate all future uses.
>It then comes back to the equipment manufacturers to test their
>well beyond the claimed ratings... but then the marketing droids want
>market the products at the test ratings! Finally the end users push
>products harder still, and sure enough, they fail.
>>Soft Teflon makes a poor choke form but hard Teflon works quite well.
>>believe it has a fiberglass mixture. Machines well and costs less
>Any brand names and sources?
IPM is one mfg and available locally from Plastics Supply Corp which I
believe is USA wide.
There are probably several others that stock but today is a holiday and
I've been unable to get more info sofar. Perhaps others have additional
The correct nomenclature is " glass filled Teflon".
73 Carl KM1H
>73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
> 'In Practice' columnist for RadCom (RSGB)
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