Neil,
>From my recollection Tufnol is a tradename for a substance which
is similar to Solid Resin Paper Board (SRBP) in properties.
Personally I would use PTFE for the job you are describing, we
(John G6YIN and myself) have used this on several 3-500Z, 8877
and GS35B amplifiers on 6m with no problems.
If I remember correctly, John has a small quantity of 12mm and
25mm diameter PTFE rod left, if not then there's an engineering
plastics supply place in Leeds where we (and you) can get it from
at reasonable prices for small quantities - like 0.5m lengths - ask
John, I'm sure he'll remember their name.
Mike G8TIC/M0VHF/M0BAA
----- Original Message -----
From: "Neil Carr" <carr.n@runshaw.ac.uk>
To: <amps@contesting.com>
Sent: Sunday, September 14, 2003 7:07 AM
Subject: [Amps] Tufnol rod
I have acquired various lengths and diameters from ¼" to 1" Tufnol rod. I
plan on using it to wind my anode choke and at HV stand-off points.
Although I see a number of articles (here in Europe) suggesting PTFE or
Tufnol maybe used in the applications mentioned, I rarely see anyone using
Tufnol.
In order to "get wise" on the pros & cons of both materials I did a web
search and found VERY little information on Tufnol rod in general. I asked a
friend in the USA who builds amps and he said he had never heard of the
stuff.
My question is:
(1) Is Tufnol a European "thing"?
(2) Is one "better" than the other?
I also heard one way to test coil former material is to check its heating
properties by placing it in a microwave oven with a cup of water (Not in the
water, this just acts as a dummy load (Food) to protect the oven). If it
stays cold then it has very little or no loss effects at RF, the web page
was for trap making ides.
Not too sure how one would use this to simulate conditions in an amp
???????, but I put my 800w oven on for 2 mins, the cup was boiling. The ¼
and ½ rods were still cold but the 1" rod could not be handled for a good
couple of mins, although there was no burning etc. I don't have any PTFE rod
for comparison right now.
Comments/advice appreciated.
Neil G0JHC
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