Is it aluminium? That will be your issue with g101I've hopefully repaired my ultrasound tank, time will tell.
About a year ago it started tripping the RCD, I took it apart to see what was going on and the PCB was soaked, there was a pinhole in the tank.
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Looking closely, there's hundreds of tiny pits. I've never had any proper ultrasonic fluid, I just use whatever's handy, usually MucOff or G101 but sometimes caustic soda, brick acid, etc. I assume once something has etched the surface the roughness creates nucleation sites and cavitation bubbles start drilling through the tank.
I hosed off the circuit board and left it to dry in the conservatory for a few months. I was thinking about lining the tank with epoxy but last night Robin Renzetti put a video on Instagram showing a repair of a vibratory tumbler with hot glue. I've already got hot glue so it's not gonna cost anything and should be easier to peel off when it doesn't work.
I didn't bother with a glue gun, just warmed the whole thing up with a hot air gun and melted glue sticks directly against the surface until I had a reasonably uniform coat across the whole bottom of the tank.
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The finished product, as far as I can tell there's no holes in the glue but I didn't go up the sides and there are some pits still exposed, I should really coat the walls too.
I ran it for a while without fitting the circuit board in case it leaked straight away. I also put a piece of foil in to check it's still ultrasounding properly, I was a bit worried by making the tank heavier I'd mess up any impedance matching the transducers and tank may have, it seems to be fine though, that picture is after half an hour, I think the foil is suitably destroyed.
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After a couple of hours, the surface of the glue is unchanged and it still seems well attached to the tank, aside from this small bubble in one corner. There appears to be water under it, I can move it around a little but I can't push it out, can't see how it got in either.
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I'll update after it's had a bit of use in anger, or it fails, whichever come's first.