Has anyone ever tried using one of these to remove grime or Vertigris? Or how about an Autoclave? If you did how did it work out for you. Thanks in Advance! Mark
I've always been curious about that too Mark. A coin dealer friend of mine has one (ultrasonic cleaner) that I think he uses only sparingly. I'll have to ask him under what circumstances he uses it, but I think it's only for extreme conditions and then only for a very short period of time. Good question and thanks for posting it. bruce
I think it would be a good approach for problem coins and highly circulated coins, but I would avoid using them on anything that has luster on it. I would like to hear results from people who have experimented on copper, silver, copper-nickel, etc to see what worked best, and how long it took.
I may just pick one up today. If I use distilled water, no chemicals at all, I can't see what it could hurt. It's nothing more than high frequency soundwaves and water. As for an autoclave not sure if that would really do much. They are high pressure steam and used to sterilize. Anyway, if I get one I'll let you know the out come. Thanks for the replies!
I'm glad to hear you're buying one Mark, because after you find out if it works or not (the operative word here is after) I can borrow it and clean my crappy counterstamps. I appreciate that buddy! Thanks. Bruce
LOL, you got is Bruce. Just got back and couldn't find a decent one anywhere. I'll prolly just get one off Ebay next week
If you mean something like this http://www.ebay.co.uk/itm/Codyson-C...deo_TelevisionSetTopBoxes&hash=item3cb9c31bf7 Then yes I have one, it does not remove the verdigris with sound, more like vibration, the infected coin is vibrated on the tray causing wear and rubbing. It will get rid of corrosion but it will also wear away the coin. I have used mine on metal detecting finds with severe corrosion (500 year old) You get the same result if you use a cloth and some metal polish.
I was going to try to suspend in the coin in the cleaner somehow. I'm going to get one and just play with it. Shhhhh, (I convinced my wife she needs on for her jewelry) LOL
If the gunk ( what ever it is) , doesn't come off with distilled water soak or acetone, it won't in an ultrasonic cleaner, even with questionable cleaning solution. I used one intended for jewelry with a plastic holder and only used one coin at a time, but it still produced microscopic scratches on the coin where there was contact. How one could suspend the coin in the solution with no contact ? I even bought a waterpik device, and cranked up the voltage with a variac, but all I got was soaked. Didn't work either, but cleans gums well still.( has a little whine every once in a while, but can't bring myself to return it to Costco after such an experiment. Read about it here starting about post #19. The rest is interesting if you are tempted with DMSO. http://www.cointalk.com/t68146/ Jim I still use Bad Thad's products and if used properly is the best I can do with little to no damage for the results.
I have tried using it too, I wasn't really happy with the results at all. I followed what little directions it came with to a T. Yes it removed "some" of the vert. The problem I have is how long should it be in there. I put in for a few minutes and nothing happens. I have also left it in for a few hours up to 1,2 and 3days. I rinsed it with distilled water and let it air dry. Then the coin got this white-ish haze. I used some modern lincolns to experiment with. I don't want to take a chance with it for any of my better copper coins. How EXACTLY are you using his product? Thanks for the reply Jim! Mark
Well I think you are doing the correct thing first, and that is experimenting. I believe I used between 50 -100 wheat cents with differing degree of problems and many BU with no problems myself to get used to its action and timing, I followed the instructions and then went from there. As the direction say, I limit to 12 hrs /side, as I know that the chance of patina change ( seems more likely with rb to medium brown ) is not worth the risk. I do use acetone as a final rinse to remove all water. Thad has said several times that the reaction is a chemical one and not a "covering" one, and I have found no ill effects doing that. For the spot removal using verdicare, the directions say use a wood toothpick, and I use bamboo food sticks that I previously soak the pointed ends. Once soaked, the bamboo seems to be more flexible and can hold more fluid ( JMHO, no recommendations besides try.) Obviously the rag/fluid method which he recommends for circulated coins should only be used with circulated coins. I liked the old verdi-gone better for removing heavier verdigris ( I have several threads on the forum on this), but the verdicare seems more protective of the coin's original patina. But the main thing learned by use is knowing when the coin can not get any better and stop, or in many cases , so bad, not to even waste time and resources. It can not cure all, but it often makes a small problem coin into a nice coin. IMO. I have no financial arrangement with Thad, and all opinions and goofs are mine. Jim edit to add: I use the bamboo sticks because I need the long length as I do this technique under my zoom stereo microscope so I can carefully see what I am doing as my eyes get a little worse each year
Using an ultrasonic cleaner requires that you understand the principle under which it works. An object to be cleaned is immersed in a liquid and a transducer is used to send ultrasonic sound waves through the liquid. These sound waves can be from 20K Hz up to 500K Hz. When the sound waves hit the object to be cleaned, alternating high and low pressure areas are formed. When the pressure goes from high to low, a microscopic bubble is formed, which immediately collapses, causing a shock wave which blasts any contaminants away from the object's surface. These shock waves can also produce enough pressure to deform softer metals such as aluminum, copper and silver. Additionally, the higher the sound frequency, the smaller are the bubbles that will form. This means that they will get into smaller cracks and scratches in the metal surface. This can have the effect of enarging the cracks and scratches. Finally, the liquid being used affects the action of the cleaner. Whatever you expect to remove should be soluble in the liquid. Water is fine for removing normal dirt; organic liquids should be used to remove oils and other organic debris. The action of ultrasonic bubbles acting on metallic surfaces is called cavitation. Besides using an ultrasonic source to create the cleaning bubbles, moving the metal through the liquid at high speeds can also produce the bubbles. This is commonly seen in ship's propellers moving through water. If the propeller is not designed properly, cavitation can severly pit and crack the propeller. Cheap Harbour Freight cleaners probably won't do much more cleaning than if you simply soaked the coin in the cleaning solution. An industrial cleaner will probably clean the coin, but might also destroy it, or at least the surface, in the process.
I've wondered whether small, consumer-grade cleaners are really powerful enough to cause cavitation, or whether they just rely on high-frequency agitation. I still haven't experimented on coins with mine, though. I've figured that I'd hold the coin with a pair of padded tweezers that span it edge-to-edge, rather than putting it in a basket. But, as I said, I haven't tried it.
O.K., davidh, I read your complete post, and found it very informative and interesting. It only leaves me with one question, since I do not own one. Do all of these ultrasonic cleaners come with adjustments for the frequency, or do you have to buy a good one, as opposed to the cheapies on ebay or at Harbor Freight? Just wondering, and thanks in advance!
I don't know of any cleaners with adjustable frequency transducers although there are some that use a sweeping frequency. I'm not sure how those perform. Each cleaner is, in theory, tuned to the frequency being used. That is, the volume of liquid must be at a certain level for the unit to perform properly.Expect to pay >$500 for a unit that is any good at all. Examples of persons who might be persuaded to clean a coin or two in their cleaners are dentists, jewellers and gunsmiths.
Thanks for ALL the info Jim. It sounds to me like I need to do more testing with those 2 products. I know the problem I'm going to have is after I do get it figured out I'll still be to nervous to use it in anything important. I will be picking up a cleaner anyway. I think it wil be a handy tool if I need it. Instead of ruining a good coin I'll just sent them off to NCS and not worry about it at all. Thanks for all the comments everyone, I REALLY do appreciate it! Mark
