Homebrew PCBs

On Fri, 6 May 2005 00:57:41 EDT, <rruss45826@...> wrote:

>
> PLEASE! I am not trying to scare you! Just be prudent and be  careful!  
> Keep
> the kids out of the way! ALWAYS ALWAYS test out a new device of  this  
> type
> OUTSIDE for the first couple of times! If your going to pull it down 2
> atmospheres normally pull it down to 3 several times as a safety check!   
> A  failure
> outside is a whole lot safer then inside!


I did not know one could pull a vacuum of more than one athmosphere ;-)
On which planet (or under how much water) do you need to be to do this?

Implosions are generally just as dangerous. while the pressure differences  
are smaller than with pressure tanks my personal theory is the lack of air  
inside is the reason why flying debris is not decelerated on it's way to  
the center. It does not stop there of course.

Testing a pressure tank is done with water, maybe a simliar approach is  
good with vacuum. I could imagine filling it with old clothes for the  
first try would help with the risk. (Using a liquid could be a problem  
with the pump and boiling..)

That said, i think with a stainless steel tank such as a pressure cooker  
the risk is acceptable.
Go to casting@yahoogroups, when i was there this very topic was discussed  
to exhaustion.

ST