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Wax and boric deposit on diamonds while resizing


#1

Hello lovely people,
I am a new member here and need some advice:

Our gold smith dips diamond studded rings into some boric acid solution before resizing them into a bigger or smaller size. As soon he heat solders the piece the boric sticks on the diamonds and does not come off despite exposing the ring to ultrasonic and steam cleaning. Even dipping the piece in ISO propyl alcohol does not clean the diamonds. As a result even white diamonds start looking gray and the lustre is reduced. Can you please help with a solution to this problem?
Regards.
Prasoon


#2

Hot water will take off the boric acid, but perhaps slowly. Much faster is a pickle solution such as sodium bisulphate or dilute sulphuric acid (caution. Sulphuric acid can be dangerous). Even citric acid will do it. However, its very important that before your goldsmith applies the boric acid, the diamonds must be totally clean. If dirt ir grease is still on them, then the biric acid wont protect the stones, and the dirt burning off will frost the stones requiring them to be repolished.


#3

Thank you very much for the kind input. We have already tried pickling with dilute sulphuric acid, hot water bath, ultrasonic cleaning, high pressure steam and ISO propyl alcohol bath however the diamonds still look greasy and I can see the fragmented deposits of perhaps boric powder and some polish wax from the rear of the ring.
We had this issue earlier where we thought that the diamonds were burnt during heat soldering so we removed the diamonds from the mount but as soon as we cleaned the diamonds with a selvet fabric they were perfect clean, however on this piece is around more than 50 small diamonds and impossible to remove and reset. Do you think a tetra bath would help?
What will be your advice in this situation?
Looking forward to hearing from your kind reply.
Best regards.
Prasoon


#4

I don’t know what a tetra bath is, but from your description, I’m going to guess that the diamonds are set without the metal being drilled through beneath the stones. Unless some other open path, such as graver cuts that extend below the girdle of the diamonds, is provided, cleaning solutions may have a difficult time. Even though dirt, boric acid, grease, etc. will somehow find a way to squeeze behind the diamonds, cleaning solutions may not be able to circulate enough behind the diamonds to be able to remove things. You can try long periods in a heated ultrasonic with a strong cleaning solutions, perhaps followed by another fairly long time in pure isopropyl alcohol. If the cleaning solution can fully dissolve the junk, then hopefully the alcohol will be able to rinse it off, and if so, on drying it should leave the stones clean. If this doesn’t work, you may not have much choice but to remove stones. Another approach would be to try and avoid the problem. Don’t coat the diamonds with boric acid, but also don’t get them hot. If your goldsmith uses a torch, have him or her hold the ring with a third hand so that the stones are under water in something like a small tin can. This should avoid most of the problem. Another would be to do the sizing with a laser welder. Then the stones need no special handling at all.


#5

If what you see on the diamonds is melted borax then pickling solution will remove it. Thats what it is for to remove melted flux and borax. Maybe your solution is too weak or you are not leaving in long enough. It works faster if it is warm. Hence a pickling pot. It can be difficult to remove without pickle. personally I don’t like borax and alcohol protection solution. Burning alcohol is hard to see and I tended to lean forward into the flames and catch my beard on fire. So I warm the piece I am soldering and dip the whole thing into Battens self pickling flux and then start heating with my torch. The flux coats the whole piece and protects it just like the alcohol and borax but no flames in my face. There should be no wax or dirt on the item before heating. If there is it will burn onto the diamonds and be extremely difficult to remove. possibly even impossible. If you can post pictures here you can get much more accurate advice.


#6

II have a few of questions…
Is your goldsmith cleaning the rings before sizing or tipping?
How hot and strong is your pickle?
How long are they staying in the pickle and sonic?
Are the stones center stones or melle?
Is your metalsmith using powdered boric acid or the coarser borax granules?
Additional info would be great for us to trouble shoot. Photos even better.
Have fun and make lots of jewelry.
Jo Haemer
www.timothywgreen.com


#7

If all else fails boil them out in lye.
If you can find it online or in your studio see the “One Last Idea” on the
last page of the April 2015 issue of the MJSA Journal for my detailed
instruction on this process. If you can’t find it let me know.
-Jo


#8

Thank you very much for your kind support, I have now tried almost everything but the problem with the wax deposition is not getting sorted out.

So we had to finally remove all the diamonds clean them and then reset them but I feel there has to be a way out.

Another query:

Can you advice on the kind of shellac or plasticised bonding material that should be now be used for holding the mounting for setting that is easy to remove from the piece after the stone setting is complete?

Thanks and regards.

Prasoon Dewan


#9

Of course theres another way out. But you need to do the thinking right.
Re the waxes used in polishing blocks/sticks. these are of 2 types, organic or inorganic the former are bees wax tallow carnuba etc. and the latter a re candle and the hard hydrocarbon distillate mineral type.
the solvent for the organic is sodium hydroxide solution .
This will dissolve all of them its very strong but always works.
the latter needs ethyl methyl ketone a tri chlorinated methanol. also dangerous. You wasting your time using alcohol.
Re your second query. dont do stones so cant help you on that one.
Ted.


#10

Thank you very much for the lovely advice. I will follow the suggestion and post your kind self with the outcome.
Regards.
Prasoon

PS: Where should I check our for the shellac or plasticised bonding material for holding the the mounting for stone/diamond setting?