Obviously, that should be a hydrometer, not hygrometer (measures
mositure content of a gas).. 
Charlie
-----Original Message-----
From: oldtools-bounces@r...
[mailto:oldtools-bounces@r...] On Behalf Of Rodgers
Charles
Sent: Friday, March 03, 2006 8:51 AM
To: James DuPrie; Peter B; Old Tools List
Subject: RE: [OldTools] Refurbishing files (long)

JD responds to Peter B's tutorial on acid sharpening of files by asking:

> Way cool! Now where does one go about scoring sulfuric acid with a SG
of 1.250?

Well, any auto parts store should be able to fix you up.  Flooded lead
acid batteries use sulfuric acid for the electrolyte.  Straight sulfuric
acid has a specific gravity of 1.8, so you can add distilled water to it
until it reaches 1.25...just buy a decent hygrometer and pay attention
to the temperature compensation chart.
Charlie Rodgers
Clinton, Maryland

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