Hydrofluoric Acid first aid

[4metals]

I have long recommended using a soak in Hydrofluoric Acid as a way to differentiate between diamonds and CZ's. I personally cannot tell them apart without treatment but I'm sure jewelers can. The problem comes when they receive a large quantity in from a stone removal refining it can take a very long time. By etching the stones in HF anyone can quickly separate the two.

Both liquid and vapor can cause severe burns, which may not be immediately painful or visible. HF will penetrate the skin and attack underlying tissues. Large or multiple burns totaling over 25 square inches of body surface area may also cause hypocalcemia and other toxic effects which may be fatal. Prolonged contact with very dilute HF solutions will cause burns.

I have always told clients who use HF to stock an Antidote Gel in case of an accident. For years I have not heard of any accidents etching stones until today. This afternoon I got a call from a client who had an employee spill some 48% HF on his exposed arm. They quickly rinsed the arm and got the Gel on the affected area, then they took him to the ER just in case. The doctor told them that the quick combination of rinsing and the topical application of the Antidote Gel saved the man from serious injury.

So that's why I'm posting this. If you use Hydrofluoric acid, get the HF Antidote Gel to have around, you never know. http://www.calgonate.com/index.php

 

[Lou]

You can easily prepare a salve-type application with glycerin (or KY jelly) and calcium gluconate. Benzalkonium chloride solutions are also helpful (they've helped me).

Most important when working with it is hygiene!! 48% HF looks like water but won't feel like it.

Lou

 

[Militoy]

I wouldn't mess around with HF acid unless I had a compelling reason to. Anyone working with diamonds and CZ on a regular basis is likely to already own a thermal diamond probe. They cost only $100-$200, and provide an instant sure-fire way to separate CZ from diamonds. Other, earlier imitations are fairly easy to distinguish from the real thing. Why risk serious injury from unnecessary use of chemicals?

 

[Fournines]

You wouldn't use HF to sort 20 or 30 diamonds.Think large volumes. Hundreds of karats at a time.

How quickly can you sort 10,000 2 point stones with a polariscope or a thermal diamond probe?

HF, while more dangerous, makes the job many times quicker.

Even then, we only do it if the customer absolutely needs to have it done.

 

[Irons]

I wouldn't mess around with HF acid unless I had a compelling reason to. Anyone working with diamonds and CZ on a regular basis is likely to already own a thermal diamond probe. They cost only $100-$200, and provide an instant sure-fire way to separate CZ from diamonds. Other, earlier imitations are fairly easy to distinguish from the real thing. Why risk serious injury from unnecessary use of chemicals?

I purchased one on Ebay from a source in Hong Kong. It was about $15. US including shipping. Works great. If you go to yard Sales or flea Markets, it will pay for itself on your first find.

I only use HF if I absolutely have to. Get a good whiff of it or some fumes in your eyes and you will wish you had never heard of it. Nasty stuff.

 

[Lou]

It is much safer to use ammonium bifluoride and dilute sulfuric acid.

Kill it with soluble calcium salts.

 

[rasanders22]

I used to use HF where I work. We used it to clean quartz tubes used in diffusion furnaces which are used in semi-conductor industry. HF is some nasty crap. HF will attack the calcium in your body which is why when it gets on your skin you don't typically know it until it is too late.

My last job was removing quartz tubes after the got showered in a combination of Nitric and HF. I'm not one for typically following safety rules but whenever I dealt with that combination I would wear triple layer nitrile gloves including a layer of actual heavy duty acid gloves, a very large acid gown, and a full face shield . The gloves would be taped to my acid gown to prevent any acids from running down under the sleeves.

If you are going to use HF, make sure you follow every safety protocol. Consider the PPE setup I described above. It is expensive but your bones will thank you.

Even with all the precautions followed I still have known 2 people that have been exposed to it. One of them had a drip of acid fall off the ceiling of our tool which landed on his head. It rolled down in between his eyes and onto his nose. We threw him in the safety shower and called our emergency response team. They took over and applied the topical cream then sent him off to the ER. He ended up being fine but accidents can happen even when you are being safe and following all the safety guildlines.

 

[Digitaria]

I was very concerned about using HF in preparing my dental scrap. This was an un-necessary danger, I just don't need, so I made one call to a dental lab and the owner, is happy for me to send him my dental scrap, for the ceramic to be removed by them with HF.

Even if it costs be a little, the safety in the service, is worth a lot. Also - we can talk dental gold and AR

 

[nickvc]

Lisa
Don't go near HF it's the most evil acid you will ever encounter.
To clean your dental scrap I'd suggest a large hammer and a block and take out your aggression freely until all the ceramics and plastic is easily removable. Any material left can be removed either by incineration or melting or by been filtered from your solutions, I don't like my material out of my sight until I know exactly what I have!

 

[Dan Dement]

Element47,

Refractometer is useless for diamonds as Diamonds are above the upper limit of the scope. For all those who depend on a Diamond Detector to separate out Moissanties and Diamonds: Don't! Lots of CVD coated Mossy's on the market. that's Diamond coated Mossy's that will fool the Best of Diamond detectors. On loose stones, I have never seen a CVD Mossy that is coated on the bottom or Pavillion but not saying they don't exist. Understand that Mossy's weight about 90% of what a diamond weights and are Double Refractive. The formula to determine diamond weight is Dia2 x depthx.0061 which will get you real close. If it is light, it's probably not a diamond.

I often have to separate out CZ's & Mossy from Diamonds on 100+ carat lots. Yes, HF is Super nasty stuff and you got to have lots of RESPECT for it. Yes, we have the GEL, an approved Enclosure, correct gloves and have had OSHA in reviewing our procedures. But I think I am going to order a kit anyway as you can't be too careful.

Thanks 4 Metals for the link!

Dan

 

[FrugalRefiner]

The moderators would like to thank all of the members who contributed to the original thread that this post was based on, as well as those who asked questions showing what was missing. Because of the extra length and interest in this thread we have created the above, consolidated version making for an easier read. We encourage all members to read, comment, and ask questions in the original thread, Hydrofluoric Acid first aid.

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