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Electronic gold testers advice


#1

Has anyone got any advice on electronic gold testers? Are they as
good as acid based testing or should one use both to determine karat
value with the most accuracy?

How good are the electonic testers at sensing gold plate and gold
filled?

Thanks for any help from those more experienced

Peter


#2

I bought a Tri Electronics GXL-24. It seems to work just fine with
certain quirks, mostly at high karats. It tests to the nearest karat
from 6 to 24. Easy to use. Only takes a few seconds. It is $400 +
depending on where you get it. They have ones that are less specific
for a lot less money, but I am using it to check both incoming scrap
and finished castings. Not a substitute for fire assay, but it is
some way of testing. The good thing about it is that it will not give
you a false high karat reading, so sometimes you need to do several
tests if it gives an unexpectedly low reading the first time.

Gold plate will test not gold. Gold filled needs to be filed before
testing because it will test as whatever the surface is.

Stephen Walker


#3

Go for the GXL-24 PRO by TRI ELECTRONICS I am using this one in
Africa and it performs well. Let me know if they give you a discount,
or if they will give you a break on the price if you buy two, then I
will buy another one. Or go to Scales-N- Tools and do the same thing
and see what your best price will be, again, let me know. Best to-ya,
Stephen Wyrick, CMBJ Gemmologist


#4

In my humble experience, not only are electronic gold testers highly
unreliable, they can be downright dangerous for your reputation as a
credible jeweler/merchant.

Long story short… I design and work in mixed metals. A few years
ago a retail buyer took one of my pieces to a jewelry store to have
the solid 14k gold section tested. The retail buyer was alarmed when
the clerk informed her that the electronic tester had confirmed that
the tested piece was not 14k gold. This was vexing for me as I
understood that the mixed metal composition of the piece would
register differently than a solid gold piece.

To put the question to rest once and for all, I called Rio Grande -
my gold supplier - to test the item with a nitric acid test kit in
the retail buyers presence. The acid test confirmed that the 14k
gold portions of the mixed metal were indeed 14k.

A stiff buff will expose gold plating immediately. If you don’t want
to damage the surface, toss the item on a digital scale. Gold is
considerably heavier than base metal or silver.

“Gold filled”, is just a synonym for extra heavy 12k gold plate, and
the gold is usually applied to the “top” surface only. Often, gold
filled will be plated (“bonded”) atop jewelers brass (or red brass)
which mimics the color of 14k.

A softened treated razor edge wheel loaded with Zam will strip away
the 12k layer in short order. A quick application of an oxidizing
agent like Hilox or Winox will quickly reveal the base metal,
turning it black almost immediately. Carat gold may darken slightly,
but the oxide can be quickly wiped away with a soft cloth.

Electronic gold testers are gimmicks for the uninformed, and
unskilled. My best advice is to avoid them entirely.

Good luck!

Michael Rogers
M. M. Rogers Design
Albuquerque, NM


#5

The disadvandage of this GXL-24 tool is that the gel which comes
together with this testing device dry’s out quickly if not used
frequently and there is nothing you can do about it.

I’ve bought brandnew inserts which where already dry in the packing!

That is the only backdraw I know of with this device.

Enjoy and have fun
Pedro


#6
"Gold filled", is just a synonym for extra heavy 12k gold plate,
and the gold is usually applied to the "top" surface only. Often,
gold filled will be plated ("bonded") atop jewelers brass (or red
brass) which mimics the color of 14k. 

Not quite, I think. First off, Gold filled stock is not made by
electroplating. It’s a mechanically (heat and pressure) bonded
laminate with a specific ratio of gold thickness and base metal
thickness. It can be applied to one side (common, as noted in your
post) or both sides. In either case, the total amount of gold will
remain the marked ratio, so if clad on both sides, the same marking
(such as 1/20 12K GF) would mean the same amount of total gold, but
it would be half the thickness on each side.

Another difference is that gold filled stock has the gold layer
actually the karat marked, such as 10K, 12K, etc. In gold
electroplate, karat designations on the plating bath usually refer
only to the color. Electroplating multiple metals at the same time to
produce a karat gold alloy in the electroplate layer is indeed
possible, but it’s far more technically complex than a simple single
anode with a single bath, and it’s not found often, especially in
simple electroplated wares. Usually found in electroformed pieces,
where the entire metal content is electroformed, rather than just a
thin plating over base metal. For the vast majority of electroplated
pieces seen, the gold layer may have an adjusted color to mimic a
lower karat or color of gold, but in general, the actual karat
content of the electroplate deposit is somewhere well above 18K. Like
22K to 24K. The reason is that in a bath containing more than one
metal, the baser metals will plate out of the baths more quickly than
the gold, because they’re more reactive. So making a stable bath that
will maintain it’s color means making it with only minute amounts of
the other metals (copper, etc) that will color the gold deposit.

The “extra heavy” versions of gold electroplate are not called gold
filled. If heavy enough, they may be marked “HGE” (heavy gold
electroplate). That’s still much thinner than even the thinner
versions of gold filled stock.

Peter Rowe


#7
"Gold filled", is just a synonym for extra heavy 12k gold plate,
and the gold is usually applied to the "top" surface only. Often,
gold filled will be plated ("bonded") atop jewelers brass (or red
brass) which mimics the color of 14k.

Gold filled is 1/20th by weight. Plated is microns thick. Gold filled
in not heavy plating. Gold filled could be any karat of gold, in the
U.S. it is 14kt.

Richard Hart G.G.
Jewelers Gallery
Denver, Co.


#8
The disadvandage of this GXL-24 tool is that the gel which comes
together with this testing device dry's out quickly if not used
frequently and there is nothing you can do about it. 

What is that gel anyway? The literature does not have much to say
about it. Is it dangerous? I am treating it like it is until I know
better.

Stephen Walker