This happened to a new torch

[poh6702]

Then just use the one u have without battery.  If it get worst then u koe

You are right, next time when go diving will use the same torch and take a pic before and after dive for the 3 scenarios.

Interestingly there are many metal casing dive torch also using either head or tail cap twist on/off and they are ok.  But from the close up look of my torch, it didn't seems to be sea water corrosion nor paint attacked by sea water. The paint (coating) on the torch looks more like platting process instead of paint, I suspect the current flow from the head through sea water then back to the body to form a closed loop, that process created a reverse electro platting process that dissolve the platting material into the sea water.

Therefore if there is no battery in side, there will not be current, then it will not get worse, secondly, if the torch is turned on, current flow directly from the body to the head and current will not flow through sea water which is higher resistance path.  That is why I really interested to test it again to confirm my logic.

[siaokao]

no need to test.. confirm electrical corrosion also call "electrolysis".

[gchew]

no need to test.. confirm electrical corrosion also call "electrolysis".

Anything that we can do to prevent this or mitigate the corrosion?

[poh6702]

Anything that we can do to prevent this or mitigate the corrosion?

The interesting question is why it happened to this torch, I know of few torches also using twist on/off design, using the body as return path and they are ok? For example the Archon W17, 1k shortie and the underwater laser pointer I just bought during ADEX.

If it is construction and material used then those who bought the same torch should have the same problem, anyone bought the same torch during ADEX and used? Any feedback?

Is it due to manufacturing defect that only happened to the torch I bought? then what went wrong?

[diver-hloc]

The interesting question is why it happened to this torch, I know of few torches also using twist on/off design, using the body as return path and they are ok? For example the Archon W17, 1k shortie and the underwater laser pointer I just bought during ADEX.

If it is construction and material used then those who bought the same torch should have the same problem, anyone bought the same torch during ADEX and used? Any feedback?

Is it due to manufacturing defect that only happened to the torch I bought? then what went wrong?

Not an expert.... but the grounding of the torch could be the issue here.... a small charge is passing through the whole body of the torch... hence starting a reaction with the seawater....

If you have a very sensitive Multi-tester... maybe its possible to measure with the battery inside the torch... is there an electric current running through the outside of the torch....

[geo88]

diver-hloc is right. The aluminum body of the torch somehow is not isolated from the battery circuit. Thus, some leak current might have earthed to the torch body. The seawater + aluminum body + electrical current = galvanic corrosion on the body. Happened to one torch I bought last time. Use it first time and similar thing happen. Bring back to shop and get to choose another model as replacement.

[siaokao]

Anything that we can do to prevent this or mitigate the corrosion?

Like the others explained, there really is very little you can do about it as they are usually design flaws.

[poh6702]

Like the others explained, there really is very little you can do about it as they are usually design flaws.

If the shop is local, go and change to another model, if the shop is oversea then depends on the price, for this case it is $36, no point pursuing but if it is $300 then will be a difference story.

Can I conclude that this might happen to only torches with body twist on/off design? Of course not all body twist on/off will have this problem.

[diver-hloc]

Can I conclude that this might happen to only torches with body twist on/off design? Of course not all body twist on/off will have this problem.

I do have a few model using the twist on/off design that doesn't have this problem.... ever since that big torchlight of mine, I only go for plastic model if I'm getting it from some China website or store... but all it all... will try to avoid getting China made and designed model if possible.