David, can you get some pictures from your buddy, perhaps a few more 
details.  What sort of vacuum are we looking at?  100's of PSI's, or what?

-Shawn

David P Harris wrote:
> My friend does plexiglass forming.  Wooden frame, kitchen oven element 
> for heater.  Large air-tanks connected to a pump.  These are pumped out, 
> then a valve opens and the vacuum forming happens very quickly. David
> 
> Roland wrote:
> 
>>> BTW, the hard parts of vacuum forming seem to be the matter of an 
>>> oven big
>>> enough for the work and creating a vacuum source (or is it sink?) with
>>> enough volume to draw down the material before the material cools out 
>>> of the
>>> plastic condition...
>>>   
>>
>>
>> Hi
>> I've watched vacuum forming done, and it was a very simple set-up. They
>> were forming polystyrene(not foam!)
>> The positive/pattern was simple wood fabrications, and there was no oven,
>> rather a big element and a few fans blowing the air down. I think the
>> vacuum part was just an industrial blower, as a sucker.
>>
>> The force required will depend on the temperature, depth of draw 
>> required,
>> thickness of sheet, resolution of pattern. Although a nice convoluted
>> surface can be obtained, the edges always pose a problem, same with
>> fibreglass moulds. Trimming them to an exact size, and polishing to hide
>> the work, is almost impossible.
>>
>>
>>  
>>
>>> A home vacuum cleaner arrangement is not really up to the task. 
>>> Besides, my
>>> earlier experiments with home vacuums lead me to believe a lot of air 
>>> FLOW
>>> is essential to avoid toasting the motors.
>>>   
>>
>>
>> maybe a powerful blower and a venturi will be better??
>>
>> Regards
>> Roland Jollivet
>>
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> 
> 
> 
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