Electro-chemical degradation of stainless steel wire in my garden Slug-o-Cuter?

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The discussion centers on the electro-chemical degradation of stainless steel wire used in a slug deterrent system in a garden. An electronic engineer designed a circuit that delivers 18V DC pulses to AWG20 stainless steel wires, which effectively eliminates slugs but leads to wire brittleness after one or two seasons. The engineer speculates that the DC current contributes to corrosion and considers experimenting with alternating voltage polarity to mitigate this issue. Basic electrochemistry principles indicate that galvanic corrosion is inevitable, and while alternating voltages may slow the process, they will not completely prevent it.

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Techno_Gardener
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My wife is an avid gardener in Puget Sound area near Seattle. But we have a lot of slugs. If you hit a slug with a brief (~2 seconds) pulse of 18V DC, the slug is finished...

I am an electronic engineer and I designed-built a circuit to produce these pulses (1/8 duty cycle) to AWG20 stainless steel wires, laid about 1/2 inch apart, across the top of the garden soil like railroad tracks. Stainless steel seems to last better than tinned copper wire or galvanized steel wire, both of which I tried before stainless steel. But after 1 or 2 seasons of this nonsense the wire becomes brittle and breaks. I expect that that every voltage pulse results in some current from the wire through the soil, depending upon moisture and natural chemicals in the soil.

I am wondering if the DC current in fact is doing this, and whether a more complicated design to alternate the polarity of the successive pulses might reduce or eliminate the wire corrosion? I did try subjecting a slug to high frequency voltage (about 25 KHz) and the slug was not affected at all, so far as I could see. That would have been slightly easier but is apparently not an option. But given that a single pulse of DC seems to terminate the slug, I do not think that alternating the voltage polarity between pulses would hurt the functionality.
 
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Basic electrochemistry tells galvanic corrosion is inevitable in such conditions. To avoid it in small lab systems electrodes are made of some noble metal, like gold or platinum (but even then electrode pitting is still possible, depending on voltages involved)

Alternating voltages won't stop the process. It can slow it, but the only sure way to check is an experiment.
 
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Thank you, Borek. In my situation, it might be more economical to fly in fresh vegetables daily rather than to plate my wires with enough gold. :-( Before someone steals the wire.

I am setting up an experiment to slowly alternate the voltage and compare corrosion results with DC. I will see what happens.....
 
What if you just hired a toad, snake, duck, chicken, raccoon, beetle, turtle, shrew or bird?
 
We do have garter snakes around. Those are busy enough making garter belts. But beyond that I will duck your question and chicken out of any attempts to cooperate with a raccoon. Do those eat slugs?
 
Techno_Gardener said:
We do have garter snakes around. Those are busy enough making garter belts. But beyond that I will duck your question and chicken out of any attempts to cooperate with a raccoon. Do those eat slugs?
Apparently so. Apperently, toads are their primary predator though.
 

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