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Broken twist drills


#1

I know every bench jeweler has had the same problem, but I am
looking for a new solution. I am hoping someone may have a technique
for removing broken drill bits from stainless steel, gold, etc. What
normally is a 10 minute job can turn into a disaster.

Gary L. Mills


#2

Mix equal amounts [1 tablespoon] of ‘Sulphate Of Potash’ and
’Sulphate Of Aluminium’ [obtainable from garden centre] in water and
simmer on low heat for about 2 hrs or until the drill bit is
dissolved. Works well in gold and silver, but i have not tried it in
stainless steel.

cjh; from sunny NZ.


#3

Hi Gary,

I know every bench jeweler has had the same problem, but I am
looking for a new solution. I am hoping someone may have a
technique for removing broken drill bits from stainless steel,
gold, etc. What normally is a 10 minute job can turn into a
disaster.

my favorite approach is to take a concentrated (almost
saturated) solution of alum (from the drug store) in a non-steel pot.
Simmering turns the drill bit into black dust in about 15-20 minutes
which falls out of the hole.

best
charles


#4

Gary,

I have always found a mixture of alum and hot water works as well as
anything, but not very quickly. I broke one off yesterday and it sat
in the mixture about two hours before the majority was removed. A few
dips in pickle and cleaner removed the rest.

Good luck.
Jon Michael Fuja


#5

Platinum, gold, or silver with a broken off drill bit… as Charles
says, simmering the alum solution helps speed the process - but if
you use a glass beaker to contain the solution - and put it in a
heated ultrasonic, I’ve found it works even faster!

Be aware that plastic containers tend to absorb ultrasound, some
more than others - slowing down the results…

Brian P. Marshall
Stockton Jewelry Arts School
Stockton, CA USA
209-477-0550
instructor@jewelryartschool.com


#6

I don’t know if you know this one already. For gold or silver remove
a amount of pickle solution enough to completely cover the piece in a
glass jar add more sparex to make the solution very strong. Soak the
piece over night. It will turn pink but will dissolve the drill bit
away or enough that it will come out. I have tried this one
successfully. It does mean more polishing but when starting over
isn’t and option. I have also hear to mix alum (it’s a spice used in
pickling food, you can find it in the grocery store) and water to
cover the piece Soak until drill bit release. I have not tried this
one. Heard it from and old timer with lots of tricks

Maegan


#7

Hello, I have always used nomal bleach at room temperature for
broken drills in gold, and once with a piece of 304 stainless that
didn’t suffer because of the bleach. Bleach takes quite a long, many
hours maybe, but in my opinion is the simplest and safest method to
remove bits of broken burs or drills from jewelery. However, try out
for yourself, is the only solution.

Bye.
Fernando F. Escudero, Spain.


#8

ALUM you get it at the grocery store. Boil the bite about 30-45 min.
and only an ash rust bit is all that is left

Don in Idaho.


#9

hello,

I would like to offer a strong word of caution about bleach and
karat gold. using bleach on karat gold can break down the gold
alloys. Bleach in any form of concentrations should not be used on
karat gold, and never on white gold alloy.

the high alkaline ph of bleach will dissolve the alloys in the gold
especially nickel and zinc. this will cause stress cracking, porous
gold that will be very brittle, breaking instead of bending.


#10
I have always used nomal bleach at room temperature for broken
drills in gold, and once with a piece of 304 stainless that didn't
suffer because of the bleach. 

I do not understand this post at all. Bleach will

1 - Contaminate the alloy of the piece of gold jewelry, making it
brittle and probably discolored, and

2 - Bleach does nothing to loosen or dissolve broken steel drill
bits.

Could you be thinking of some other chemical?

Lee Cornelius
Vegas Jewelers


#11

I’ve only read one mssg. of this thread - something about bleach.
Why a person would use bleach to presumably remove a broken drill bit
is a mystery. Hydrochloric acid does the job quite nicely - AKA
Muriatic acid, or Concrete bleach. Of course, if there’s a pearl, or
turquoise, or some other stones, they must come out. If you don’t
know how to handle acids - DON’T.


#12

With different metals you will always have the less noble metal
corrode ( dissolve) first if you put them together in a conductive
electrolyte. Gold will always be more noble than a steel. Steel
doesn’t like chlorides in general so a chloride or hypo chlorate will
get the steel. With stainless steel you can have active and passive
states as you can see somewhat by looking at the electrochemical
series.

http://www.efunda.com/materials/corrosion/electrochem_list.cfm?sort=com.

The corrosion potential is the difference between the higher
potential and a lower one. The lower one goes first and the bigger
the difference the fast the reaction goes. Bleach would not be the
best thing to use with long immersion with a gold alloy. It will get
the drill, but free chlorine can screw up the alloy. OK with steel.
Use alum or your pickle which will be a sulfuric acid solution as a
convenient electrolyte. Steel or iron can be either passive -
positive - high on list or active negative- lower on the list a
depending on its state — generally assume to be active with a drill
or tap.

jesse


#13

Hello,

the liquid I refered to by “bleach”, is called “LEJIA” in Spanish:
it’s a colourless liquid (maybe a slight yellow hue) that is in
every home (at least here) for washing and for cleaning floor
tiles, specially in bathrooms. When I looked in the dictionary for a
translation the first word that came up was “bleach”. The second
word was “LYE”. If both words refer exactly to the same chemical,
well, there might be a few “weakened” pieces around in my city.
However, the “lejia” totally disolved the broken drill bits, and I
didn’t noticed any discoloration on gold (white or yellow, always
18k) or porosity over the surface or soldered joints.

But Please, Please, if lye is the same as bleach, let me know to
stop using this way of disolving ferrous bits on gold.

Fernando F. Escudero, Spain.


#14

Lye and what most North Americans call bleach are not the same
thing. Although I’m not sure which is nastier to humans as either is
not nice. (I’ve never used either on gold.)

Lye is sodium hydroxide (Or perhapse potassium carbonate?) And
Chlorine Bleach is Sodium Hypochlonite

And I think both are unkind to soft parts, like fingers.

Cheers,
Norah Kerr


#15

Fernando,

Bleach is a chlorine compound (sodium hypochlorite solution) It is
used to clean clothing and floors and it is also as a disinfectant.
It is also corrosive to metals. It will damage nickel white golds and
other metals by what is called stress crack corrosion it creates
inter granular corrosion allowing the metal to crack along the
crystal boundaries. It probably is dissolving the drill bits by
electrolysis. It is a poor choice for this due to its ability to
cause the stress crack corrosion. There is an article about this
phenomenon at

Do Chemicals Effect Your Gold?
https://orchid.ganoksin.com/t/do-chemicals-effect-your-gold

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#16
When I looked in the dictionary for a translation the first word
that came up was "bleach". The second word was "LYE". 

Lye is sodium hydroxide (NaOH) which would not be used in laundry.
Lye is chemically reacted with a fatty acid to make soap but would
not be used in its original composition for laundry. In its unreacted
form, it is dangerous to handle and would ruin many types of fabric.)

Bleach is sodium hypochlorite (NaClO), usually about 5%. Bleach is
used to whiten laundry and as a disinfectant. Our family also uses it
to clean and disinfect shower tiles.

Howard Woods
Looking forward to sunrise in th beautiful foothills near Eagle Idaho.


#17

Bleach and lye are two separate chemicals. Unfortunately, they both
seem to be called “LEJIA” in spanish, so I can’t help you there. Does
the bottle have a chemical name? Sodium Hydroxide (NaOH) is Lye,
while Sodium Hypochlorite (NaOCl) and Calcium Hypochlorite (CaOCl)
are bleach.

Good Luck!
Lee Cornelius
Vegas Jewelers


#18

Lye can be very effective to clean gold. In one shop I worked in we
used a strong solution of lye and water heated on a coffee cup
warmer to clean gold chains and rings that we didn’t want shaken in
the ultra sonic. I have never tried it to remove broken drill bits.
But didn’t notice any bad effects on the gold or its alloy

Maegan


#19
Lye can be very effective to clean gold. In one shop I worked in
we used a strong solution of lye and water heated on a coffee cup
warmer to clean gold chains and rings that we didn't want shaken
in the ultra sonic. I have never tried it to remove broken drill
bits. But didn't notice any bad effects on the gold or its alloy 

I often use lye to soak off organics and greases from the backs of
durable stones such as diamonds and corundums prior to heating or
soldering. Ditto for chains, etc. Overnight in a sealed glass jar
works fine. (The lye, of course, is dissolved in water.)

Learned this at a bench job years ago in a jewelry store. The usual
cautions regarding fragile stones and materials and remember that
lye is CORROSIVE.

Red Devil brand is what I use.

Andy cooperman


#20

Hello All again,

thanks a lot for shedding light on my ignorance (i’m the guy of the
bleach). Now a question about ALUM. I’ve got at home a deodorant
stick (“Cristal Deodorant” is the commercial name) that looks like a
translucent piece of crystal and in the composition part of the label
there are just two words: AMMONIUM ALUM. Is this the Alum you refer
to? I have seen that there are many kinds of alum. I also have at
home a small white rod of a soft stone-like material that is used to
stop bleeding from tiny cuts one can make himself when shaving (by
rubbing the point of that rod on the tiny cuts), and i’ve been told
this could be made of ALUMBRE (spanish for “alum”). If the Ammonium
Alum is the one you have refered to, I should have to smash the
"deodorant" to powder, since I haven’t been able to find any other
source for alum around here.

Regards. Fernando F. Escudero