[Amps] Life of tubes in ham service

[Jim W7RY]

Oh... And I have used small screws, (2-56) and nuts to hold Teflon sheet 
together for tube chimneys.


73
Jim W7RY
Happy New Year!

-----Original Message----- 
From: Jim W7RY
Sent: Friday, December 29, 2017 7:46 PM
To: AMPS
Subject: Re: [Amps] Life of tubes in ham service

Lots of Teflon and silicone on eBay.

I have also successfully used turbo charger hose. Buy it by the inch. I use
it on my 3CX800 amplifier. It's silicone sheet with a cloth cover. Used to
connect the exhaust system to a turbo charger on truck and heavy equipment
engines.


73
Jim W7RY


-----Original Message----- 
From: Roger (K8RI)
Sent: Friday, December 29, 2017 7:32 PM
To: amps at contesting.com
Subject: Re: [Amps] Life of tubes in ham service

Silicone rubber sheet wrapped into a cylinder works fine and requires no
machining. The ends simply overlap. The joint can be made a number of
ways including RTV. There was a RED high temp RTV available at one time
although the regular "Silicone" RTV should work  (smells like Acetic
Acid). Alpha and others have used this for years.  !/16th" Teflon sheet
should also work fine, but OTOH it is slippery and not as easy to work
with. .  The nice thing about using sheet is adding a taper is simple.
Speaking of simple, working with these sheets is simple and requires no
special tools.

At one time I had a bunch of the red, high temp rubber and the red high
temp Silastic RTV


I believe the 1/8th inch Silicon rubber might be available at many
automotive shops.

73, Roger (K8RI)

On 12/28/2017 Thursday 6:39 PM, Stan Gammons wrote:
>
> On 12/28/2017 01:15 AM, Roger (K8RI) wrote:
>> "I think" the GI-7B would be an easy tube to convert to transverse 
>> cooling to replace the no longer available Eimac tubes in the MLA-2500s. 
>> The coolers are easily replaced by removing a single screw. A lathe and 
>> mill could easily build custom radiators. It'd be a simple, straight 
>> forward conversion.  IM products?
>>
>> 73, Roger (K8RI)
>>
>
>
> I haven't decided on the cooling method. But it will probably be something 
> along the lines of a plexigass cages with the fan mounted so the air flows 
> up around the tubes and out the holes in the top of the cage.  I've seen 
> some use a machined piece of teflon for chimneys. A piece of teflon tubing 
> that size is rather pricey though.
>
> I ask on this list about IM products awhile back and the general consensus 
> is it's not a problem.
>
> Seems like the MLA-2500 is one of the many amps that others have 
> converted.
>
>
> 73
>
> Stan
> KM4HQE
>
>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps


-- 
Roger (K8RI)


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