So you've finally got an ultrasonic! Maybe a $150 import that you'll replace in 13 months (because the warranty is 12), or a $600 used Branson that'll last for years, but either way, you're now in the big leagues. But you don't have enough money for two.
You've got your 4% phosphoric acid, or 5% citric acid, or 50:50 household vinegar solution for verdigris removal, and your scent-free dishwashing solution (or Extreme Simple Green, or, or...) to emulsify hydrocarbons, but which one do you put in the U/S basin?
Me, I use the acid. Verdigris removal is the one step that seems to benefit best from the occasional U/S boost. But YMMV. In any case, what happens when you have some stubborn junk that needs some ultrasonic detergent assist to lift off? You can pour out the acid and rinse and pour in the detergent, but that quickly gets to be a PITA.
Most of us just float a container with the required solution in our U/S basin and let it do its thing. Some even just use water in the U/S as a medium to carry sound waves and always float a container of acid or detergent in the bath. I was chatting with @Tanks A Lot after our most recent Seminar (thank you, @Tanks A Lot for your superb input!), and he corrected me about floating a glass container in the bath. I had taught that a plastic yogurt cup was inferior, because it's flexible walls would absorb the sound waves. He said "No, Rob", and something about "acoustic impedance", but I'll let him weigh in with his better store of knowledge.
Anyway, I still disagreed, and went to Grok3, which supported glass over plastic. When we chatted again, he laughed about AI and said that Grok was incorrect.
So...
I did an experiment.
Here are three strips of aluminum foil which had been suspended in the ultrasonic for 26 minutes.
On the left, a strip just hung in my phosphoric acid bath heated to 60C. In the middle, a strip hung in a plastic yogurt cup, and on the right a sturdy glass pickle jar.
Well, oops! 26 min in hot acid just completely ate the foil in the basin. In the middle (yogurt container), two chunks chewed out of the plastic cup strip, and on the right (glass jar) a chunk and some edges chewed out of the glass jar strip. What did I (re)learn? Don't leave your regs in the acid unattended, or your chrome will be gone! But I couldn't really answer the question about which container was better, because the results were too similar. Clearly, ANY container is a huge barrier, so that speaks to choosing one solution or the other, rather than using water and always floating a cup of some material. Those transducers have a good, but limited lifetime, so direct exposure to sound waves is clearly better.
So I repeated the experiment with a shorter (10 min) exposure:
Here's hot Phosphoric acid with no container:
Here's hot acid in a plastic 1 quart yogurt container:
Here's hot acid in a glass jar:
As you can see, no barrier is clearly better. But if you have to have a barrier because you're floating incompatible detergent in a basin full of acid (or vice versa), the plastic WAS a little better than glass, Grok notwithstanding. Here's a toast to @Tanks A Lot and real knowledge, compared with AI and scraping the Internet.
But the diminution in force was significant, so the search is now on for a better plastic.
Here's my first, next experiment (because it was sitting in the recycle container in the kitchen).
Maybe thinner will be better. I'm open to suggestions.
Hey, @Tanks A Lot ! Teach us about acoustic impedance!
You've got your 4% phosphoric acid, or 5% citric acid, or 50:50 household vinegar solution for verdigris removal, and your scent-free dishwashing solution (or Extreme Simple Green, or, or...) to emulsify hydrocarbons, but which one do you put in the U/S basin?
Me, I use the acid. Verdigris removal is the one step that seems to benefit best from the occasional U/S boost. But YMMV. In any case, what happens when you have some stubborn junk that needs some ultrasonic detergent assist to lift off? You can pour out the acid and rinse and pour in the detergent, but that quickly gets to be a PITA.
Most of us just float a container with the required solution in our U/S basin and let it do its thing. Some even just use water in the U/S as a medium to carry sound waves and always float a container of acid or detergent in the bath. I was chatting with @Tanks A Lot after our most recent Seminar (thank you, @Tanks A Lot for your superb input!), and he corrected me about floating a glass container in the bath. I had taught that a plastic yogurt cup was inferior, because it's flexible walls would absorb the sound waves. He said "No, Rob", and something about "acoustic impedance", but I'll let him weigh in with his better store of knowledge.
Anyway, I still disagreed, and went to Grok3, which supported glass over plastic. When we chatted again, he laughed about AI and said that Grok was incorrect.
So...
I did an experiment.
Here are three strips of aluminum foil which had been suspended in the ultrasonic for 26 minutes.
On the left, a strip just hung in my phosphoric acid bath heated to 60C. In the middle, a strip hung in a plastic yogurt cup, and on the right a sturdy glass pickle jar.
Well, oops! 26 min in hot acid just completely ate the foil in the basin. In the middle (yogurt container), two chunks chewed out of the plastic cup strip, and on the right (glass jar) a chunk and some edges chewed out of the glass jar strip. What did I (re)learn? Don't leave your regs in the acid unattended, or your chrome will be gone! But I couldn't really answer the question about which container was better, because the results were too similar. Clearly, ANY container is a huge barrier, so that speaks to choosing one solution or the other, rather than using water and always floating a cup of some material. Those transducers have a good, but limited lifetime, so direct exposure to sound waves is clearly better.
So I repeated the experiment with a shorter (10 min) exposure:
Here's hot Phosphoric acid with no container:
Here's hot acid in a plastic 1 quart yogurt container:
Here's hot acid in a glass jar:
As you can see, no barrier is clearly better. But if you have to have a barrier because you're floating incompatible detergent in a basin full of acid (or vice versa), the plastic WAS a little better than glass, Grok notwithstanding. Here's a toast to @Tanks A Lot and real knowledge, compared with AI and scraping the Internet.
But the diminution in force was significant, so the search is now on for a better plastic.
Here's my first, next experiment (because it was sitting in the recycle container in the kitchen).
Maybe thinner will be better. I'm open to suggestions.
Hey, @Tanks A Lot ! Teach us about acoustic impedance!
)
) I went down this road for my cheap, Harbor Freight, Chinese US machine. These fit nicely and support on the rim of the US if not fully floating and have 3 sections to separate small/fragile parts from the bruisers ...
.)
