# New or used equipment for assays



## Jordan1 (Aug 23, 2018)

Hi, 

I want opinions on the purchases of new or used equipment when purchasing a xrf and an analytical balance. 

I have found prices varying from 1000 us - 5000+ us . 

I have also found used equipment websites that offer warranties with the products they are selling. 

Please let me know your opinions. 

Thanks, 
Jordan


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## goldsilverpro (Aug 24, 2018)

Jordan1 said:


> Hi,
> 
> I want opinions on the purchases of new or used equipment when purchasing a xrf and an analytical balance.
> 
> ...



I'm an old timer with 50 years in this business and, personally, I would never have a desire or a need for an xrf. I wouldn't have one unless I were sorting base metal alloys on a large scale. I certainly wouldn't use one for precious metals. There are other ways to do things, much better ways, in my humble opinion. Precious metals are too valuable to trust a digital readout. I like fire assay because I can see, hold, and weigh the actual gold.

I see 100s of used .0001g analytical balances on Ebay ranging from $50 to $3000. I have used about every type, from those where you balance the left-right swings to chain-o-matics to those with changeable internal weights to the newer ones where you just put what you're weighing on the pan and read it out. I still could get along with the old Christian-Becker Chain-O-Matic, but I think my favorite is a Mettler or Satorious of the type with internal weights. They're almost as fast as the newer ones, where you just put it on the pan and read it out. Being old, I'm definitely an analog guy. For example, I hate computerized AAs or digital rectifiers. I like to watch those meter needles move.

The biggest problem with a used balance, especially one that has movable parts, is the shipping, unless it's purchased from a balance company. An individual usually has no idea how to pack a mechanical balance. For example, if he doesn't know how to stabalize the beam or the internal weights, the balance will probably be severely damaged during transit. Some of the better internal weight balances had built-in devices for locking down the beam and the weights. Some of those used mechanical balances could be bought for a song if the seller could convince you that he knows what he's doing. 

I've had 2 balances that were wrecked in shipping. One wasn't packed right and the other one was dropped by the UPS driver.

I noticed on eBay that there are new .0001g balances for $418. China, no doubt. I have no idea about their accuracy, etc. 

Things like accuracy, linearity, and repeatability are everything.
https://watermark.silverchair.com/labmed35-0048.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAbAwggGsBgkqhkiG9w0BBwagggGdMIIBmQIBADCCAZIGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMr7jSbkuE4vzGMg8-AgEQgIIBYyi8Ic5Zd3cX2U-mAjrpcJ00tnlWGASNUZVg_CReNZC_-YLp3RhPCXlprnROTDpJH0PXPeWJAEE61VVTrkhA9sj7YWRFxyrGmbBhGDx16YIDVjDLVAtwpgzQSvNfhuBGqeUc7o4QOQrc4LlVoZaQJC4nyU5urIThmeTEN-b6VLg7sVRqVl9AE1gOSM1n6MlvqZ92MhVmQPiISTcTdqYlz42uzf7q6dgkZqAjCcbrXTCsg3ALD3EP6S1-Sm8yfHVFoUuWwRaBCxKpggJTOQanzB_7O5JlHatncWLE-g6m8qdDnsCsuoYGeUPGd8eYYOYg6Rogc6SpS8HLh-TbyhCaZGBneVEfwrhOrnlE8MPjCO-2MTvXscYj5W0t-x7DQ5h7_MgrytIz8wvWj_B0COBBGokHBJR5_AM41eSl5MSYSAOXa5ZEWhtjmy773fLnhXUkDd1B7dKhy1p0stIHToeFdfq-iCs

In the past, I have bought highly calibrated mg weights to check out an analytical balance, but a highest grade one, say a tiny, aluminum, 1mg one, might cost $50-$100. You can't touch them with your fingers (oils) or you'll ruin them.


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## snoman701 (Aug 24, 2018)

An xrf that gives you reliable enough numbers to pay on is at least $20,000usd used. Even then, you have to be able to feed it a uniform sample, and make appropriate use of the data.





Sent from my iPhone using Tapatalk


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## nickvc (Aug 24, 2018)

The question I want to ask is why do you want assay equipment?
If your buying scrap then xrf is ok if you know how to use one and it’s limitations, if you are looking at fire assay equipment then why bother unless you have quantities of assays to do?


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## Jordan1 (Aug 26, 2018)

goldsilverpro said:


> Jordan1 said:
> 
> 
> > Hi,
> ...




Thanks for all the replies guys.

Goldsilverpro,

How should i get the company to pack the balance if it is shipped from the US to Australia.

I have found a neat used Mettler for $800 + US.

Thanks


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## Jordan1 (Aug 26, 2018)

Goldsilver pro,

I have seen the China scales online, though i do not think they will be accurate enough once it gets down to the .001 level.

Had anyone bought a cheap scale like these that can tell me if they are accurate? 

Thanks


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## nickvc (Aug 26, 2018)

I went back and read your old posts and if you are refining dore bars then my advice is spend the money on reliable scales as any error could more than wipe out any potential profit, I’d also make sure you take good representative samples to perform your assay.


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## Jordan1 (Aug 26, 2018)

nickvc said:


> I went back and read your old posts and if you are refining dore bars then my advice is spend the money on reliable scales as any error could more than wipe out any potential profit, I’d also make sure you take good representative samples to perform your assay.




Hi Nickvc,

Thanks for your comment.

I want to get the mettler i seen. It is used but if calibrated and transported properly i think it should be fine.

A buddy of mine works in a lab and he says Mettlers are the best of the best . Goldsilver pro speaks pretty highly of them also.

What is everyones experience with mettlers? For accuracy?


Thanks


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## nickvc (Aug 26, 2018)

Mettler make fine balances and scales and are hard to beat so long as the working innards are not damaged, again as mention by GSP I believe getting standards to test aren’t cheap but probably well worth the money if you are going to be processing in quantity and need to be sure your assays are spot on.


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## goldsilverpro (Aug 27, 2018)

Since the gold mining industry is big in Australia, I would expect there are used balances available. Another good place to look is in schools and Universities, I would call around and talk to the Chemistry teachers - many have old ones in storage, especially when they switched from the internal weight ones to the all-digital ones. If they don't have any themselves, they might give you other leads. Just make sure it's a .0001g or better. You'll also need a heavy, sturdy table to stabilize it. With a .0001g balance, I've never gone so far ay buying a 300 pound granite slab for it - just a heavy sturdy table will do. 

As far as shipping goes, the manual that came with it should give packing and shipping instructions. If the manual is lost and, if you know the model number, instructions are almost always available somewhere on the internet. Try to find those for the specific maker and Model#, if you can.


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## Jordan1 (Aug 28, 2018)

Thats great, thanks guys i appreciate the advice.

Will look for some here in Aus.

The equipment in Aus is usually pretty expensive, though better then getting a broken balance because of shipping.

Thanks


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## cuchugold (Aug 29, 2018)

goldsilverpro said:


> Jordan1 said:
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> > .
> ...


 Thanks for your posts GSP. :G 
What is your opinion about the accuracy/precison for the fire assays since the newest super-precise balances have been introduced?. I'm also reticent about XRFs, ICPs, etc, etc. Except to estimate/verify high purity metals. Thanks in advance.


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## goldsilverpro (Aug 30, 2018)

cuchugold said:


> goldsilverpro said:
> 
> 
> > Jordan1 said:
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It's been too long. To answer you, I would have to do the same searching that you could do. Also, every balance manufacturer produces the accuracy, precision, repeatability, etc., for their products. Lou or 4matals might have a quick answer for your question. Just keep in mind that the last digit on any balance, is always unknown. For example, an accurate weighing of .0027g on a .0001g balance is, at best, somewhere between .00265g and .00274g. These are the 2 rounded off limits (both low and high of the number .0027. A reading of .0001g is somewhere between .00005g and .00015g. A potential error of 100% too low or 50% too high. The closer your reading to the scale limit, the less accurate the weighing. However, to even see a .0001g bead in the middle of a cupel, you will most likely need a magnifier. Removing that bead from the cupel and cleaning off the bone ash, is quite a challenge.

I don't know what you mean by super-precise balances. Do you have an example. I think the gold mining industry has used .00001g and .000001g micro-balances for maybe 100 years, or more. I've never used one, but I think the maximum weight limit on some are 1g, or less The accuracy of any balance I've ever used, is operator dependent, to some extent.


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## cuchugold (Aug 30, 2018)

Thanks GSP. I'm wondering about the case of a 1g sample weighed in a microbalance of lowest reading 0.000001 g, or even 0.0000001 g. I used it once in a sample drilled, without using a cupel. I got repeatability at 99999 purity for 3 samples of 1g. Hence my question: How accurate is the limit with gravimetric methods alone, no ICP, nothing else. Maybe Lou, or 4metals can answer, as you said. Cheers.


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## Jordan1 (Sep 6, 2018)

So after doing some research i found that most used analytical balances are in US. I contacted American Instruments because they offered a 90 day warranty with their products. The salesman has told me that if they ship it to Australia, they can not offer the warranty with it because they do not have any technicians here. 

I rang Mettler Toledo this morning and told them what i was looking for. They stated to me that they do not deal in used balances. A lady from Mettler Toledo rang me this afternoon with a pretty reasonable price for a brand new Mettler. 

This is the analytical balance :

https://www.mt.com/au/en/home/products/Laboratory_Weighing_Solutions/Analytical/Standard/ME_Analytical/ME_54.html

It comes with a 12 month warranty that i want to negotiate to see if i can get a year or so extra. 

Price: $2150 AUD - delivered 

Let me know what guys think ? 

Cheers


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## Cheyenne1944 (Nov 1, 2018)

I am an Inorganic Analytical Chemist and have used many types of equipment. The XRF is of limited value - it is great to find a percentage of particular element between Na and U of sometimes as light as Li, but for general use if you a weighing under 100g I use an old 1950's Christian Becker SB-2 Chain O Matic for results down to 1/20th of a mg. Works great and beats the digital readouts. Electronic types can be effected by everything from current variations to flickering florecents. Were you aware that gravity is NOT the same all over the world. So a single pan balance can give wrong results as can a piezo crystal type? I have measure gravity in two spots 200 miles apart where one place it was 9.8 and the other was 10.0. That is the same as 32 ft/sec and 32.65 ft/sec. If you sent $5,000 dollars of gold and the receiver weighed it on a single pan balance he might figure it was $4,901 depending on the value of g where he was. If you use a balance, Two pans, your results will be the same all over the world and even on the moon. So I prefer a balance and its repeatability. For many things I use an old Detecto from the 1800's that my great grandfather used in his assay office it is still good to the 1/100th of a gram. Anyhow, to be accurate anywhere in the world, use certified weights and a balance. MC


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## cheyenne (Nov 19, 2018)

I am an inorganic analytical chemist and I find that after using the newer electronic balances in the crime lab, my favorite is still the AB-2 Christian Becker Chain-o-matic for ease an repeatability. It is also easy to repair and calibrate. When dropped during shipping, there was no problem. I had the shipper remove the pans, the stirrups, the beam and wrap them all in paper, stiff paper in the case and put the parts inside. It was quick to clean, re-assemble and calibrate, Now when they dropped my single pan Mettler, electronic scale it was a hassle with claims - "Oh, it doesn't look damaged or dented!", "Yeah, well try weighing 0.0001 grams on it with repeatability!" My family has been in the assay business for 100 years so we have a collection of balances. The older single pan Ainsworth 10N was a good subtractive balance, but its optical scale could easily get skewed. REMEMBER a single pan scale, is not always a balance! It will give you different weights around the world because G, the gravitational constant is not the same and using the same piezo/electronic/magnetic scale could give you a difference of up to 2% in different parts of the world. A balance will give you the same answer everywhere because even if G is different, it pulls on both pans equally where that is not the case with electronic balances. If you want to see accuracy in action, try weighing a volatile liquid and watch the weight change as it evaporates. Or check a balance by weighing a fingerprint! MC


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