Hi there, any help much appreciated!
So got a broken drill bit in a 9ct white gold ring that I can’t get out… tried soaking it in safety pickle all weekend but it hasn’t disolved! Any ideas what I can do to remove it? See attached photo
Kind regards,
Luke Brient
Hydrochloric acid will not touch Gold,
but it may damage the staining and surface that is exposed if its not pure enough.
It seems that it is protruding a bit, is it drilled from the inside?
If it is already through, you could try to punch it lightly from each side alternately
What kind of stone is it?
Can it take some heat?
Here’s a link to a Ganoksin article of how to dissolve a broken drill bit using alum.
When all else fails, you can always grind it out with a diamond bur. You’ll enlarge the hole, but you’ll remove the broken drill.
Hope that helps!!
Jeff
Oops! That link just goes to the main video page.
Here’s a more direct link:
Jeff
Thanks Jeff! Any idea where I can buy Alum in the UK? Don’t seem to have it in our supermarkets, is there a UK equivalent?
Shoot! I don’t know about availability in the UK? It’s available on Amazon if that helps.
In the US it’s usually in the area with all of the spices in a grocery store.
Alum is used to make pickles you eat as in dill pickles.
Do you know if alum works for carbide drill bits? 
I’ll be honest, I’ve never had good luck with Alum dissolving drill bits, but others swear by it. Maybe someone else on the forum has more experience than me and can answer this. Sorry!
Jeff
According to our chums at Wikipedia, tungsten carbide “is resistant to acids and is only attacked by hydrofluoric acid/nitric acid mixtures above room temperature.”
Well, that’s not good news! hydrofluoric acid is one of the most dangerous acids around. Definitely not something to fool around with.
Like I said, I’ve had good luck grinding out broken drill bits with diamond burs. Maybe that’s the best solution. Or punching it out like was also mentioned.
Sorry this is such a headache!
Jeff
I’ve had very good luck dissolving drill bits with alum. You may have to fiddle with the concentration a bit, and it works best if the solution is heated. It also helps to periodically clean away the black residue that forms when the alum solution is working.
Hydrofluoric acid is definitely no joke! I wouldn’t touch it with a ten foot pole if you can avoid it. And I got my degree using it…
Drilling it out with a diamond bit is the way I’d go too. Not ideal, but it’ll do the trick.
Hi,
i just had a few random thoughts, after looking at your photo…
1)-saw through the shank and open it up:
if maintaining the surface is important, and you do not want to open up the drill hole size…what about sawing through the shank, coming in, from the sides, toward each side of the drill bit… and then stretching open the shank to release the drill bit…then soldering it closed again…
it may seem like a drastic option, but it might result in a cleaner outcome than trying to drill/ dig out the drill bit…
2)-excavate around the drill bit to expose enough shank to grab onto with pliers, and twist it/ back it out…then drill the hole clean and plug with round wire, solder it, and start again…or not, if you will be drilling the hole larger or cutting a stone seat, wtc…
just my morning musing…
julie
If it’s a high speed steel bit. Just use a carbide round bur and bur it away.
I carried HF, HCl and H2SO4 in belt case in the field as a geologist for over 20 years and never had a problem with any one of them. Acid is acid, you have respect them.
I used regular Coca-Cola- the original kind- it dissolved a broken drill bit for me - no harm to the gold. I left it for 24hours.
Imagine what it does to us. Just a thought. I like a bit of it once in a while myself…Rob
With respect, hydrofluoric acid is a terrifying chemical that is quite different and considerably more dangerous than most other acids.
To get a broken drill bit out of your piece, soak it overnight in warm water to cover and a couple tablespoons of Alum (from your grocery store). It should be gone in the morning. Leave a bit longer if necessary.
