[Amps] nylons

[R.Measures]

On Mar 15, 2005, at 8:56 PM, Tony King - W4ZT wrote:

> Tomm, John and the group,
>
> I agree about not using nylon in high RF fields. Best to use something
> better.  Going directly to John's question about 3/8"x1/2 inch
> insulators, instead of going to the hardware store and buying nylon,
> place an order with MSC for virgin teflon rod. You can drill and tap it
> for any sized screw you need.

Even though it is excellent around RF, the trouble with TFE is that it 
cold-flows and it has little strength. .
For strength, RF-tolerance and workability, G-10 is hard to beat.

> A 12" length that is 3/8" in diameter
> lists for $3.59.  That looks like 3.59/22= $0.16 each! Not bad for an
> insulator that you don't have to worry about (I allowed an inch for
> waste in saw cuts). They also carry fiberglass rods, tubes and sheets,
> micarta, silicon rubber and many other useful items.
>
> Look here: <http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=1790>
> Their home page is <http://mscdirect.com>
>
> MSC is a good outfit to deal with.  They have a GREAT on line catalog
> and can deliver almost anything you can imagine in the way of hardware,
> materials and tools.  I use them all the time and highly recommend 
> them.
>
> 73, Tony W4ZT
>
>
> Tomm Aldridge wrote:
>
>> John,
>>
>> In my opinion, the use of Nylon for general standoffs in an RF 
>> amplifier
>> is perfectly fine if a bit of thought is given as to the temperatuer
>> they will be exposed to.  I would not consider Nylon for a tank or 
>> plate
>> coil former nor for the building of capacitors (as a dielectric).  I 
>> use
>> a machined Nylon couple between my two roller inductors in my balanced
>> tuner and have seen no issues there.  Supporting your plate coil on
>> Nylon would not be advised due to both RF fields and high temperature.
>> Instead of ceramic standoffs consider G-10 glass reinforced epoxy 
>> stock.
>>  You can get it from McMaster Carr in a variety of shapes, including
>> tubes suitable for coil winding.
>>
>> Tomm, KD7QAE
>> going down in frequency since 1975...10GHz >>> 1.8MHz
>>
>> John Irwin wrote:
>>
>>
>>> I made the original inquiry about the nylon I found at the ace 
>>> hardware store .  These little cylinders are the same size,shape as 
>>> ceramic standoff insulators commonly used in amplifiers.  I was 
>>> looking for a low cost replacement for ceramic standoff insulators 
>>> made expensive by the "PARTS MERCENARIES" that seem to have infected 
>>> our hobby today.
>>> It is likely I will fork over to get ceramic as I don't want to take 
>>> chances, with nylon melting ,softening. or crystallizing. What with 
>>> big bangs,kapow,parasitics, spark gaps and other problems.  I will 
>>> play it safe.  Nylon goes back to ace.   what about glass?
>>>
>>> Nylon cylinders cost a quarter.        ceramic, well a lot more.
>>>
>>> anyone know of a low cost source for ceramic standoff 
>>> insulators,3/8" diameter,length 1/2" or something similar.
>>>
>>> john kb9tc
>>>
>>>
>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org