[Amps] Kitchen Aid Silicone for Chimneys

[W0UN -- John Brosnahan]

At 05:14 PM 4/14/2006, you wrote:
>Well, It seems there are issues with using PVC or CPVC close to lots of
>RF, so I now consider it a potentially risky option.
>
>Silicone Sheet, on the other hand, seems to be widely used.  It has been
>available from sources like McMaster Carr (sp?).
>
>BUT
>
>The kitchen departments are now loaded with objects formed from it, from
>cupcake forms to spatulas.
>
>Yesterday I found, at TARGET, a Baking Mat made by Kitchen Aid from the
>stuff - an 11 x 16.6" piece of fairly thick silicone sheet.  With some
>Permatex Red RTV high temp silicone I intend to fashion a GS-35b
>chimney.  Also, I plan to have the chimney come to the top of the anode
>cooler, totally enveloping it, rather than just pushing air into the
>base.  (any comments as to why or why not??)
>
>Main thing here, is it is readily available, not requiring a mail order
>and shipping exercise, or much travel time.  It was $12 with enough
>material for 2 tubes.
>
>Any comments on this material in an RF rich environment?
>
>Thanks, and the chimney thread demonstrates the great value of this
>reflector - lots of great information from knowledgable folks!
>
>73 Kevin K7ZS


Good tip.

All Alpha amps use chimneys made from silicone rubber with generic
RTV as the glue.  The glue secret is to clamp the lap joint for 24 hours
with some pretty decent pressure -- like a pair of those plastic, spring-loaded
clamps on a pair of strips of stiff metal of thick plastic on each side of the
joint.

--John  W0UN