Great input as always. I really appreciate it. I just looked at Mettler 
briefly and I would rather spend the $4 - 6K on a better Oven/Chamber 
and then error on the side of caution. Leasing is not an option.

Leif Erik Laerum


Stadem, Richard D. wrote:
> Also realize these balances can usually be leased if you only need to
> perform a bake study for a particular PWB.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
> Sent: Wednesday, October 14, 2009 12:14 PM
> To: [log in to unmask]
> Subject: Re: [TN] Weighing PCBs
>
> Hi Leif - one company that produces capable balances is Mettler. Realize
>
> that many printed wiring boards are too big to fit on the available 
> capable balances and you will need to be using a excised sample. The 
> balance required for measuring moisture loss/gain needs to have 4 places
>
> of accuracy to make the measure correctly. Good Luck.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
> Leif Erik Laerum <[log in to unmask]> 
> Sent by: TechNet <[log in to unmask]>
> 10/14/2009 11:44 AM
> Please respond to
> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
> Leif Erik Laerum <[log in to unmask]>
>
>
> To
> [log in to unmask]
> cc
>
> Subject
> [TN] Weighing PCBs
>
>
>
>
>
>
> Technetters,
>
> We would like to have the capability to weigh PCBs in order to evaluate 
> moisture content. IPC-TM-650 2.6.28 (proposal inside IPC 1601 (draft) ) 
> suggests I need a scale with accuracy down to 0.0001g. I have a hard 
> time finding something and I was wondering if anyone has "real world" 
> experience weighing PCBs and what type of scale they use.
>
> I have a 12 layer 8" x 10" board that weighs around 4 oz. If we assume 
> for sake of argument that this board has reached it's maximum moisture 
> absorption level. After baking this bone dry, what percentage (ballpark)
>
> weight reduction should we see?
>
> Any advice is appreciated.
>
> Thank you.
>
>   

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