[Amps] Customs drilled a hole in my GU74b / 4CX800s

[Steve Thompson]

>> *Btw: Is it true that these tubes contain Beryliumoxid and thoriated
>> thungsten?
>>
>> What is the health risk going out from an opened tube?
>> *
> 
> 
> Beryllium oxide is not a problem if it remains a solid mass. However, 
> drilling or sawing it creates dust which it incredibly toxic if inhaled.

I think that particle size and density in the air are important 
factors. As I understand it, serious problems are normally only 
seen in people who have long term exposure to fine dust.

That aside, the ceramic in these tubes, and almost all external 
anode tubes is Aluminium oxide which is not generally regarded as 
toxic - but the edges are razor sharp when broken, so handle with 
care.

The mounting blocks for 8873 and similar conduction cooled tubes 
use BeO. I have some conduction cooled tubes custom made for the 
UK 353 tank radio which have BeO as part of the body of the tube 
but I think they are between rare and unique in that.

Steve