[SEL] Finding ground off serial numbers

[Peter Scales]

Hi Peter

Typically, the revealing of stamped numbers on steel is done by polishing
the area where the number used to be, then acid etching it.  An etchant can
be made up by mixing 10% concentrated nitric acid in 90% methanol (you can
use methylated spirits or ethanol, but there is a risk with ethanol, see
http://en.wikipedia.org/wiki/Nital).  We used to use this for revealing the
grain structure of welded steel test specimens - 10% Nital.

All the best

     Pete
-- 
Peter Scales  

> -----Original Message-----
> From: sel-bounces at lists.stationary-engine.com 
> [mailto:sel-bounces at lists.stationary-engine.com] On Behalf Of 
> Peter Lowe
> Sent: 06 November 2008 10:03
> To: ATIS; Oldengine.org
> Subject: [SEL] Finding ground off serial numbers
> 
> Hi Guys
> 
> I have a technical one for you gurus
> 
> When I worked at the steel mill in Newcastle, Australia. the 
> laboratories were able to detect and read things that have 
> been ground off.
> The company engraved all their tools with BHP, the rouges 
> would grind that off and steal the tools. If caught at a gate 
> bag inspection with suspect tools, they could take them to 
> the lab and detect the engraved BHP. By stamping or engraving 
> it alters the grain structure of the steel and it can be 
> picked up by some sort of spectrograph.
> Does anyone in the US know of such a technique, I have a R&V 
> guy in Texas that needs to lift a serial number from a 4hp 
> triumph line engine.
> 
> Regards
> Peter Lowe
> R&V Engine Registrar
> Australia
> Ph: 61-266453455
> http://www.oldengine.org/members/plowe/rv-engines/rvpage.htm
> http://www.oldengine.org/members/plowe/rv-engines/rv-register.htm
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