Anyone familiar with "Scanning guns"

[Wayne S]

In a recent alloy analysis service which I think I speak for is greatly appreciated. Anyway
a lot of samples came back with readings of Bismuth. For anyone familiar with these scanning guns, would tin give a reading of Bismuth ?
Two of the samples I had tested were bought as 2.5/2.5/95
one reading was ; 3.64/.28 SN/2.87 Bi/ and 90.65 PB,
the other read 2.39/0.0 SN/2.99 Bi/92.15. Thus it seams to me that this scanner is reading BI for SN

[Any Cal.]

A lot of the samples had both, so I don't think the gun is making a mistake. My understanding is that Bismuth is a byproduct of manufacturing lead and antimony as well as other materials; my guess is that it just happens to be present in most of the stuff we use, so accumulates over time.

[mongoosesnipe]

The scaning guns use X-rays to determine alloys and there is an element of error but since its reading tin in your simple and not antimony its probaby reading antimony as bismuth, antimony is in the same metal group as bismuth and is the gun is calibrated for bismuth (which is often added to steel alloys for increased machinability) and would give a similar X-ray signature

The X-ray gun I used when I worked in a specialty alloy shop wold read wood as aluminum when the scan things they are not familiar with they just interpret it to the closest known data in the gun

[sqlbullet]

For best results with lead alloys you need one that is calibrated for heavy elements. A general calibration pack usually works, but is really designed for metals a scrap yard commonly sees like steel, aluminum, etc.

[Any Cal.]

I did some reading on this, here is what happens (theoretically). The gun is built and calibrated at the factory, and reads 90-some elements as it comes. Some models can be calibrated to special needs, but it requires known samples, and in some cases, software changes; this is a rare need, like when trying to accurately determine trace elements in large samples, like determining chromium contamination in soil.

Not sure what a "scrapyard calibration pack" is, it doesn't appear to have any relation to the gun that is used. In any case, lead I had done at a scrapyard showed lead and tin just fine, so I don't think that is an issue.

Perhaps someone with years of experience with the guns could chime in, but I can't see any reason to doubt the gun so far. Even when readings seem to be wrong, the procedure is to sand down the surface and clean with alcohol, not calibrate the machine, and calibration doesn't appear to be as simple as holding a piece in front of the gun and pressing 'zero'.

Wayne, your sample happened to show a lack of tin, but many showed bismuth along with tin and antimony.

[sqlbullet]

Just to clarify, "scrapyard calibration pack" is a term I coined, not an industry phrase. Checking Niton's (http://www.niton.com/en/metal-and-alloy-analysis) website, they advertise configurations for "Scrap metal recycling/scrap metal sorting" among six others. The salesman I spoke with there about three years ago was testing a new configuration, which was targeted at pawn-shops. He thought it would work best for lead alloys. I would guess it was the pre-cursor to what they call today the "Precious metals & jewelry analysis".

These are software changes, as mentioned. It had to do with which PIM they had on the back of the gun. They are not calibration in the way you would calibrate a radar gun, but a software calibration that has to do with what the software does with potentially ambiguous photonic energy signature.