[Amps] Need chimney material info

[Will Matney]

Ron,

You can also use paper electrical tubing ( if you can find the right I.D.), or thick fish paper about 30-40 mils thick. The temperature rating for fish paper is within what the tube runs at normally plus some. Keep in mind it is used as insulation on hot running transformers and motors. Just roll up a piece as long as you want it. Make the I.D. about 1/8" larger than the tubes radiator. Actually, tight fitting chimneys dont let the outside ring of the radiator to receive any air. The small 1/16" gap all around gives more cooling surface this way. To mount it, they make some small brass angle brackets available from Mouser and Allied. Put about 2-3 around the bottom circumference and use screws to hold it to the chassis. You can use screws or pop rivets through the paper to hold the brackets, or even glue them on. This stuff is real easy to glue up and stays using cyanoacrylate (super glue). The problem with using silicone is joining the seam. Some I've seen tried using Permatex sealant, and some used staples as it's hard to bond silicone with standard glues. You can find small rolls of fish papaer most of the time cheap on eBay.

Best,

Will

>w2cqm at juno.com wrote:
>
>>It appears that silicon rubber is the most expeditious way to fabricate
>>chimneys for the 3cx800A7. Can anyone direct me to a supplier? Thanks,
>>Ron W2CQM/3 
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