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Ultrasonic cleaner and damage to hands

the power rating for 45khz cleaners ranges from about 60 watts for
1 liter tanks to 125 watts at about 4 liters . Even a 5 gallon unit
would only be about 500 watts. This power is delivered to the
tank walls by transducers cemented to the tank wall. A lot of the
power will be transferred to the tank wall. Some energy will be
lost and ineffective. a 1 liter tank wetted wall surface is about
375 cm 2 . A 5 gal ( 20 liter ) tank would have a wetted wall
surface of about 3750 cm2. This is obviously way below the
medical instrument figure. Efficiency of the cleaners is probably
not too high also. I have no idea how close these guesses are to
real delivered efficient use, but they shouldn’t be very far off.

Jesse

    Hello all, There is a HUGE difference between the frequencies
used by ultrasonic cleaners and ultrasound medical equipment. 

No doubt. My point is that there is little, if any, evidence that
ultrasonic cleaners used by most jewelers cause any long lasting, or
even short lasting damage to tissue or bone.

    So he just reached in and fished the slices out. He did this
many, many times that night with the big ultrasonic tank on the
entire time. 

Was this a typical jewelers ultrasonic?

        By the next morning he could not hold a pencil, his
fingertips hurt so badly. Basically, the doctor told him that the
sound waves had given him the most complete set of stress fractures
he'd ever seen. Not to mention the soft tissue damage -- the
pinkness and swelling was due to bleeding deep in the tissue. 

How would we be privy to what “doctor told him”?

    Since the sound waves travel especially well in liquids, and
you are basically a liquid in a sack made of skin, you can see how
there is a potential problem here. 

Not being a physicist, I would be more inclined to assume that most
of our tissues behave more as a gel. Absorbing the kinetic energy and
converting it to heat.

        As for the issue of tissue damage, check out the
"Guidelines for the Safe Use of Ultrasound, Part II -- Industrial
and Commercial" at the Canadian government's informative Consumer &
Clinical Radiation Protection site. Specifically:
www.hc-sc.gc.ca/hecs-sesc/ccrpb/publication/safety_code24/toc.htm
Click on the "contact exposure" headings. They do mention the
scarcity of research on this topic. There has been one study with
volunteers, who did confirm that putting your fingers in a tank can
hurt. (I would suspect that there are ethics problems in pursuing
this further with human subjects.) The article says: "Contact
exposure can in some cases provide nearly 100% energy transfer to
tissue... 

This is the beginning of a paragraph that addresses ultrasonic
humidifiers in particular.

The next couple of paragraphs, including the one which you cite
below refer to devices operating in the "low MHz frequency range"
which, to the best of my knowledge is at least an order of magnitude
above the operating range any ultrasonic cleaner that I have had
experience with.

    For example, high-power ultrasonic waves are used in ultrasonic
cleaners and cell disintegrators because of their destructive and
violent effects. It is certainly reasonable to assume that
relatively intense cavitation activity occurs in the water (or
solvent) baths of such devices.... "The literature on devices such
as ultrasonic cleaners and tissue homogenizers is confusing: these
devices do not appear to be as hazardous as expected, given the
effects they were designed to create. Nonetheless, although reports
of biological effects are surprisingly rare, exposure to the
liquid-bourne ultrasound from these devices clearly can cause
tissue injury, and protection measures are necessary." 

This paragraph is very confusing. It is very late and I wonder why
it was written.

“Nonetheless, documented cases of actual tissue damage are rare. In
one documented study, exposure to ultrasound in ultrasonic cleaners
operating at frequencies between 20 and 40 kHz was reported to have
caused pain in the hands of the volunteers.”

I took my daughter climbing last night. She complained of hand pain.
Does that mean anything other than her hands got a workout? Should I
not allow her to climb anymore?

I found section 4 with “Guidelines for Safe Use” amusing. I am sure
that these make sense with particularly large or powerful cleaners, I
suspect that this section is not meant to apply to jewelers.

Like anything in this universe, something that is safe in one form,
instance, or amount may be hazardous in another form, instance, or
amount. There are literally millions of examples in the natural
world. Take X-rays for example: we experience them in background
radiation every day, and they are not particularly harmful in small
dosages (like tooth diagnostics at the dentist), but are quite
deadly in large dosages.

I have had ultrasound done as a diagnostic during my pregnancy; as
well as ultrasound therapy for muscle tissues. That does not mean
that those forms of ultrasound are the same as what is used in a
cleaning tank! Follow the precautions stated by the manufacturer,
and use those precautions as minimum guidelines – they are there to
try to keep you safe.

Hello all

I was talking to a doctor about two years ago about cleaning ones
hands in the ultrasonic. He said it is a cess pool of germs. Even
though the heater has the solution about 170 degrees the germs are
there, especially if you have splits in your fingers like allot of
do in the winter time.

I use plastic coated tongs that need replacing about once a year.
The best I found to remove rouge from your fingers can be found @ a
automotive store or @ Wal-Mart. Its a citrus hand cleaner with a
little grit. Works very well . SAVE YOUR FINGERS !!! Keep them out of
the sonic.

The Ringdoc is right , drop a piece of foil in the sonic. That will
be your fingers in a couple years !!!

Tony @ CECENAS JEWELRY

    I have not doubt that these warnings come with good
intentions, however, they do not cite any medical or scientific
data or to back up their info. It is not uncommon for
manufacturers to be overly safety aware with the looming dangers
of litigation. 

Except where required by law manufacturers tend to not publish
health effects. There are a couple of reason for this One is most
don’t run any testing for health effects unless it is mandated by
law mostly because of the huge expense involved in doing them. Also
if they do any tests that find health effects and get sued after the
test results are in the fact that they knew about the health issues
will generally make the litigation go worse for them.

      I am sure that most manufacturers don't list all the effects
 to limit law suits.
    Why would you think that? 

For chemical products the manufacturer is required to provide us
with a MSDS that defines the health hazards of their product but
equipment manufacturers are typically not required to provide any
such They can just say “don’t put your hands in the
tank while in operation” they dont have to add what will happen if
you ignore their advice. If there is any data available to the
manufacturer that suggests that exposure to ultrasonic cleaners is
damaging to the bones and joints they may be fearful that by
publishing it they will get a ton of lawsuits that try to blame the
manufacturer for any sign of arthritis or other normally occurring
joint pain.

    I might be mistake, but I believe that these machines are
powerfull enough to remove most deposits without even using
solvents. Is that wrong? How many watts were these machines
butning? Is it really fair to include them for comparison to the
machines that most jewelers use? 

It was a 1500 watt cleaner which seems like a lot when compared to
your 200-400 watt cleaner but the power per cubic inch was not that
much more than our cleaners.

All I can say is I belive that I will continue to not put my hands
into a working ultrasonic.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau

The instructions that came with my ultrasonic state clearly that you
should not put your hands in it while it is in operation. Dee

I bought my ultrasonic used and since it was my first ultrasonic I
wasn’t sure it was working. So while it was running I stuck my
fingers in it (OK, I don’t always approach every problem with logical
thinking). No immediate effect but after having my fingers submerged
10 seconds or so I felt the bones in my fingers and finger joints
aching so I knew this was not a good thing. I too clean my fingers
in my ultrasound, (I use Simple Green – Thanks Orchid!), but it is
with the ultrasound turned off. It’s been a few years ago I can’t
say it caused any permanent damage but my exposure was a one time
experience. From the aching I felt in my fingers I would guess
regular exposure to ultrasonics made for cleaning jewelry, dental,
parts, etc… could cause permanent damage. No scientific data to
back up my theory. Just someone who was dumb enough to see what
would happen. And for you Jeff Foxworthy fans it may have proved I’m
a redneck… :wink:

Rick Copeland
Silversmith and Lapidary Artisan
Colorado Springs, Colorado
http://home.covad.net/~rcopeland/

Ultrasonic cleaners WILL do damage to your tissues. Ultrasonic
cleaners by their nature degas the liquids that are in the tank.
Your blood and tissues have dissolved gasses in them. Here is an
experiment you can do to illustrate what ultrasonic cleaners,
regardless of power or frequency, will do to your tender parts.
Take a glass and put an inch of fresh coca cola in it. Now immerse
this glass in a ultrasonic cleaner that is up and running. Watch and
learn what is going on in your tissues and blood when it is subjected
to ultrasonic energy. The difference between ultrasonic cleaners and
ultrasound or lithotripsy is the focus of the sound and power levels
used. You can rationalize all you want but damage to tissue and blood
is done when you put your fingers in a running ultrasonic cleaner.
The damage is cumulative!

Mike & Dale, Lone Star Technical Service, Your ultrasonic cleaner repair
guys.

It is human nature to give little credence to something that is
"unseen". For example, you can’t see ultrasonic waves (except the
motion of the water in the machine) therefore it doesn’t exist. You
can’t see nitrogen gases dissolved in water therefore "the bends"
doesn’t exist. You can’t see carcinogens in the smoke of burning
tobacco, therefore it doesn’t exist. Human experience is confined to
the immediate, tangible and apparent. But if something is
inapparent, non-seen, non-tangible; it doesn’t exist. That is what
the Scientific Method is all about. Someone hypothesizes that
something exists (the bends, ghosts, carcinogens in cigarette smoke)
and sets about trying to prove it. You can’t see E. Coli in water:
the water tastes absolutely perfect but it’s there and enough people
died to prove it. Ultrasonic waves can be used to break down calculi,
it stands to reason, that, with enough energy, ultrasonic waves can
probably do damage to sensitive tissue. Just because one can’t see
the damage, doesn’t mean it doesn’t exist. So, the ultrasonic
machine that we use to clean instruments here, though the waves are
fairly low energy, and it appears to not do damage to my hands
immediately when I put them in the water, I can’t know what may or
may not happen down the road, therefore I’ll avoid putting them in
the ultrasonic machine in the future until proven otherwise. I
remember a certain jewelery instructor (not Gerry) who said that
certain things we do in the class all the time were definitely not
toxic and I know now this to be not true. She didn’t know. She
wasn’t going out of her way to hurt me, but now I err on the side of
safety knowing that people are usually not perfect. I rely on no
one. And that may be the best way to be.

I believe the original question wasn’t about having his hand in the
sonic but rather holding onto something that was partially in the
sonic. Is there a transfer of vibration that would run up to his
fingers and hand that could be detrimental over time?

Thanks, Marta

Good morning, I just want to thank everyone who had some advice on
how to get crystal surface on gold, especially the help on growing
the size of the crystals. I am trying everyones advice this week.
We’ll see what happens. Just a note on the onging debate on sonic
cleaners. I have used cleaners for years at different places were I
have worked, and find that some of them are much more damaging than
others. I have arthritus, have had all of my life, not the deforming
kind, thank goodness but general and sporadic pain most of the time.
Some cleaners that I have used have been down right painful to even
stick my fingers in for just 2 or 3 seconds to pull out a chain
hanging on a frame Some have done nothing. So I suggest not
sticking your fingers in, but I know that sometimes it happens. We
as jewelers and crafts people use materials all of the time that are
dangerous. We just sort of get used to them and forget their
potential for damage. It never hurts to be more cautious, no matter
what we are doing. Thanks again for the help, Dennis

    I believe the original question wasn't about having his hand
in the sonic but rather holding onto something that was partially
in the sonic.  Is there a transfer of vibration that would run up
to his fingers and hand that could be detrimental over time? 

Yes it will, metal is a very good conductor of ultrasonic energy. It
will transfer the energy through the metal into the fingers. The
energy will be reduced in power but still can cause problems.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau

All I can say is I belive that I will continue to not put my hands
into a working ultrasonic. 

That’s probably a good idea just in general. It really boggles my
mind that people are still adamantly trying to defend putting hands
into the ultrasonic. I mean, as far as jewelry goes, our hands and
our eyes are pretty much our entire income-makers, right?

I mean sure, it might seem silly to be overly cautious, but I
dunno…I’d rather take a few extra seconds with tongs and hand soap,
or a few extra dollars for a hanging basket, than risk ruining my
hands. Whatever your personal choice is in terms of shop methods,
that’s fine…but I always think it’s better to encourage the safest
route possible in anything relating to work. Don’t discourage shop
safety! People used to think cadmium was safe to work with! Marie
Curie handled uranium! ^_^;

–M. Osedo
http://www.studiocute.com

    Is there a transfer of vibration that would run up to his
fingers and hand that could be detrimental over time? 

That is the question I answered that I can’t see that there will
be enough energy left to transfer to a solid object outside the
bath. Not to hands in the bath.

jesse

Hi everybody - let me first state I don’t even own an ultrasonic
cleaner but since I thought I might one day buy one, I continued to
read this thread. However, I’m now finding that this issue has
become a circular discussion made up of “yes, but…” explanations,
or “well, I have done it…”. We all know at this point that a
number of you think it is okay to put your hands in and an equal
number think not. So either accept the info provided by people in a
position to know about this equipment and their findings that it is
not safe to put your hands in the ultrasonic and “keep your hands
out of the machine” or don’t accept any of the info provided and
continue to do what you are doing now - “putting your hands in”… In
either case, to continue to discuss this, argue about it, dissect
it, and suggest the “yes, but…” explanations, will lead us
nowhere. Could we maybe move on now. Thanks to all who shared their
and let’s hope that no one damages their hands using
this piece of equipment. As for me, IF I ever buy one, it’s for sure
I’ll keep my hands out.

Kay

Great answer. To put it in simple words its like a hot stove. If you
are really concerned about whether it is good to do or not, either go
ahead, do and accept the consequences or don’t do it all. No use
going on and on about it. It you hold something by a section not in
the ultrasonic solution , its not going to hurt you, so go ahead ,
hold it , clean it and forget it.

rcp

Hi folks, All sound travels as a series of successive compressions
and rarefactions of the conducting medium. This diagram may help
visualise this:

| | | | | ||| | | | | | | | | | ||| | |

No sound compression rarefaction compression
<-- direction of travel

(Optional math: If we plot the pressure against time, we will get a
superposition of sinusoids.) The frequency of the sound is simply
the number of compressions per second, or hertz (which means
compressions per second.) For audible sound, the frequency is
between about 20 and 20000 hertz (= 20 kilohertz, or kHz.) Anything
above 20kHz is ultrasonic. The energy of the wave (or the amplitude)
is the magnitude of the compressiond or rarefactions; for a wave (in
air) of low energy, like voice, variations in pressure of 35
millionths of atmospheric pressure are fairly normal (the human ear
is sensitive enough to detect a bee’s wing dropped onto it from a
few cm.) The speed of the sound depends on the medium it’s
travelling through; for air it’s about 334 m/sec, though it’s very
much higher in liquids and solids, where atoms are very much closer
together (in water it’s about 1500 m/sec). Frequencies higher than
about 50kHz in air are attenuated so heavily that they are
effectively not transmitted, though in liquids and solids,
frequencies of several million hertz (megahertz, MHz) are common
(ultrasound imaging equipment uses about 5 MHz, though the energy
level is very low. It uses the fact that sound travels at different
speeds through different materials, and the different absorbtion
rates of tissues, to build its pictures. The minimum distances it
can measure are of the order of one wavelength (wavelength is the
distance between successive compressions - so it’s the speed of the
sound divided by the frequency) so with these frequencies accurate
measurements of less than half a mm are possible.) It’s easier, from
an engineering viewpoint, to produce ultrasonic frequencies, because
smaller transducers are required. The boiling point of water at sea
level (one standard atmosphere) is 100 deg. celcius. As the pressure
drops, so does the boiling point, so that it’s about 35 deg. on top
of Mount Everest. Because sound consists of compressions followed by
rarefactions of pressure, high energy sound can yield high vacuums,
followed very quickly by high pressure. Consequently, if living
tissue is exposed to high energy sound (of any frequency) water in
the cells can boil, leading to areas of very low pressure, which are
then re-compressed, giving rise to gas bubbles. Gas bubbles in
living tissues can cause many different problems: in blood vessels,
it’s called an embolism, and can block veins and arteries, killing
dependant cells; in nerves, it can trigger random firing and
twitches as the nerves are cut off from the brain; in joints, it’s
called the bends - yes, it’s the same thing careless divers get -
and can, if untreated (in bad cases, even if treated), stiffen the
joints. It may also contribute to arthritis. Since it leads to cell
death, long-term exposure is cumulative. High energy ultrasonic
devices are being used in medical experiments to perform
non-invasive surgery (see, for instance,
http://www.icr.ac.uk/education/studentships/terHaar1.html) So, Tina,
in answer to your question, holding the cast tree in the ultrasonic
cleaner can lead, in the long-term, to tissue damage. The risks are
reduced by hanging the tree on a hook and holding the hook, but to
eliminate the risks, it should not be touched while it’s in contact
with the cleaner. Danny Mitchell

Danny, Thanks for the disertation on sound waves. It was a great
tonic to spark the imagination and to help visualize what sound
really is and how it works.

A couple of points.

    As the pressure drops, so does the boiling point, so that it's
about 35 deg. on top of Mount Everest. 

In fact, water on the top of Mount Everest will boil at 78C or 172F,
note the atmospheric pressure @ 29,000 feet,
http://wwwsam.brooks.af.mil/af/files/fsguide/HTML/Chapter_02.html A
calculator for the boiling point of water is @
http://www.biggreenegg.com/boilingPoint.htm

    Because sound consists of compressions followed by rarefactions
of pressure, high energy sound can yield high vacuums, followed
very quickly by high pressure. Consequently, if living tissue is
exposed to high energy sound (of any frequency) water in the cells
can boil, leading to areas of very low pressure, which are then
re-compressed, giving rise to gas bubbles. 

I wonder why I can add a beaker of liquid, especially water and find
that it never boils in the ultrasonic cleaner. Why would water in
tissues do this? hmm… After thinking a bit, I remember. These are
mostly microscopic bubbles that collapse as quickly as they are
created. In fact, in a contained medium such as living tissue, they
may not even be created at all. I would like some substantiation
before I would assume that the bubbles are a reality. That is really
my point to the my original post.

    Gas bubbles in living tissues can cause many different
problems: in blood vessels, it's called an embolism, and can block
veins and arteries, killing dependant cells; in nerves, it can
trigger random firing and twitches as the nerves are cut off from
the brain; in joints, it's called the bends - yes, it's the same
thing careless divers get - and can, if untreated (in bad cases,
even if treated), stiffen the joints. 

The formation and collapse of bubbles in living tissue is quite
different than the bends. The bends is caused by disolved gases
particularly nitrogen, forming bubbles after being compressed into
the tissues. Unless properly recompressed, these bubbles do not
collapse at all. It is watched for particularly closely in dives of
sixty feet of more for sixty minutes or more. At this depth,
pressures of nearly two additional atmospheres, with time, will allow
an additional two liters of nitrogen to disolve into the body. This
gas begins to escape from the tissues as bubbles when the diver
arrives at the surface. Just like fizz from a soda.

For sure, it can and will cause embolism and a whole lot of other
symptoms including the possibility of catastrophic failure.See
http://www.rescuediver.org/med/bends.htm

    It may also contribute to arthritis. 

Can I get a cite on this?

    Since it leads to cell death, long-term exposure is cumulative. 

Cumulative? Usually, this adjective is reserved for types of
polution, such as heavy metal accumulation, asbestosis or silicosis,
some type of damage that the body cannot undo. These materials can
not, to the best of my knowledge, be removed from living tissues and
therefor the damage is called cumulative, as the continued behavior
that started the problem, will increase the concentrates of these
poisons. Normally, dead cells will be replaced with new cells, except
with the age old problem of old age. If death of cells ever occurs
from the misuse of jewelers ultrasonic cleaners, I would expect them
to grow back. I can’t prove this today, but I am in search of proof
of the damage that I keep hearing of in his forum.

    High energy ultrasonic devices are being used in medical
experiments to perform non-invasive surgery (see, for instance,
http://www.icr.ac.uk/education/studentships/terHaar1.html) 

Fascinating stuff happening here. From the link. " If the energy
carried by the ultrasound beam is sufficiently high, the cells within
the focal volume are killed (ablated), but cells overlying and
surrounding this region are undamaged."

Note that the beam is a focused high energy beam. The surrounding
tissues are undamaged. I doubt a one hundred twenty watt jewelers
ultrasonic cleaner can claim a high energy output or a focused beam.
My ultrasonic cleaner is further weakened by the fact that the heater
is included in the120 watts.

    So, Tina, in answer to your question, holding the cast tree in
the ultrasonic cleaner can lead, in the long-term, to tissue
damage. 

Maybe to old age, if you hold it long enough. This begs the question,
how much of the energy in the ultrasonic cleaner do you assume travels
up the tree into Tina’s hand? Why would it stop at the wire? For that
matter why would it stop at her hand. Maybe it travels through her
head on into the ether. Perhaps we should be sure to turn the unit off
whenever imersing a piece. I can see how the folks that service
cleaners will be making a couple of extra bucks now. I think that I’ll
be picking up stock in the electronics parts companies. There will
soon be a rush on switches!

My purpose in my original post was really to get a real authority to
tell us what dangers there really are. Note that I will be the first
to admit the I spent the first half of my adult life acting like and
idiot and in my later years I often find myself believing that I have
grown into a moron. (For the uneducated, that was once an upgrade of
about 25 IQ points.) I have done everything wrong.

Today, I want to know not only when and where to change but possibly
more importantly why. I just can’t accept without some proof that
cleaners used in jewelry shops are harmful.

Bruce Holmgrain
JACMBJ
http://www.goldwerx.com

I wonder why I can add a beaker of liquid, especially water and
find that it never boils in the ultrasonic cleaner. Why would water
in tissues do this? hmm.... After thinking a bit, I remember. These
are mostly microscopic bubbles that collapse as quickly as they are
created. In fact, in a contained medium such as living tissue,
they may not even be created at all. I would like some
substantiation before I would assume that the bubbles are a
reality. That is really my point to the my original post. 

Take a beaker of acetone or alcohol and place it in the ultrasonic.
The acetone will most notably show the effect of the energy of the
sound waves. The reason it can be seen in these two and not in water
is because of their lower boiling points. It takes less energy to
make a noticeable amount of gas form.

The rumor I have always heard was that ultrasonic waves deteriorated
bone marrow, but that is only rumor and I don’t have time to verify
it. I know if I place my hand in the wrong place in my ultra sonic
it causes a sharp pain inside the finger. Common sense says that if
it hurts do not do it. That is evidence enough for me that it is not
a good practice and I usually try to avoid it.

This begs the question, how much of the energy in the ultrasonic
cleaner do you assume travels up the tree into Tina's hand? Why
would it stop at the wire? For that matter why would it stop at her
hand. Maybe it travels through her head on into the ether.

The energy doesn’t travel up the tree and into Tina’s hand. Were
dealing with waves. Waves propagate outward in all directions until
they “bounce” off of an object or dissipate to a low enough energy
that the are undetectable. What you feel when you hold a part in the
ultrasonic, a part that extends outside

the fluid so that you hand is not submerged, is the effect of the
waves moving the part. The part then moves your hand. Through this
chain reaction it would be logical to assume that the transfer of
energy through this process is significantly inefficient so that no
harm would result. If your really paranoid wear cloth gloves.
Remember were dealing with sound waves. Sound waves can only
propagate by causing molecules to shift. That is one reason we use a
dense fluid medium inside an ultrasonic. The material in the gloves
would containa significant amount of airspace inside its structure
to dissipate nearly all remaining waves emanating from the parts
vibrations.

Matt