'Dive' proofing a Petzl Duo

I'd like to be able to use the same helmet for dry caving and the very occasional dive. My duo is screwed to my lid so am wondering if anyone has any tips on making it waterproof for shallow ish dives (say 10m?, if deeper all the better). I hope to eventually upgrade to a Nora but inn the meantime I like my duo and want to avoid having to talent off for dives.

Thanks
Matt
 

blackholesun

New member
Some people have apparently filled watches and torches with mineral oil to make them dive suitable. You might be able to fill the head of the duo in this manner, though I'm not sure what you'd do with the battery case, other than hope or dry it out quickly afterwards.
 

Joel Corrigan

New member
Bit of an old topic but i don't log on much!  A mate of mine dived to 120m depth in Coniston Copper Mines years ago with his Duo on his helmet & once his head cleared in shallower water he realised that it (the Duo, not his head) was still working fine.  He was less sure if it was still doing it's job at depth, though.  I'm not a fan of those lamps but I was fairly impressed at that. 
 

Pitlamp

Well-known member
This is an extremely useful question and I'm glad Matt asked (because I'm also very interested in knowing the answer).

The fact that a Duo works during and immediately after a dive isn't entirely surprising. However, how many times could this be done before slow but inevitable corrosion of components starts to result in intermittent or total failure?

However, Matt was more interested in shallow dive capability. I remember several years ago meeting "madfi" on here in Castleton. She was off for a dive in Peak Cavern, wearing dive torches and a Duo on her helmet. I queried this and she explained she'd been doing shallow dives with this set up for about two years, without problems. She also told me she reckoned that the Duo was good to go as deep as -10 m without water getting in. Long and bitter experience with leaking and failing lamps over the years would still make me very careful and I pass on this comment merely as part of all information you can take into account when making your decisions. (In other words, don't blame me if you mess your lamp up!  ;))

Anyway, the above may or may not help. Good luck and please let us know if you sort this query definitively.
 

Simon Beck

Member
Done absolutely shed loads of diving with my Duo - although most of it was shallow and sub 6-7metres - but it's still going strong after ten years..
 
Since asking this I have done several dives with the Duo on my helmet and also tested it underwater.  Admittedly its only been shallow stuff (Dub Cote, Bagshawe, Home Bank, Frakes, Langstroth sumps, Rowten sumps). I have turned it off and on underwater which probably isn't the best idea as I think the switch would be the weak point, but its been OK. I open it up and let it dry after a dive.

I did take it off for a dive in Capernwray as I was going below 10m.  Long term I will upgrade to a Nora or some such.

Someone on another forum did contact me about a custom housing etc, but the costs involved are pretty high.  Personally having had a look (as a non-engineer) I don't see what else could be done to make it more waterproof without getting into the realms of cutting more o-ring grooves and the like. The chances of me having the equipment or talent to do that without knackering my light are pretty slim.
 

Pitlamp

Well-known member
Matt - you said you open it up and let it dry after a dive. Does it actually get water in or is that just precautionary? If it does leak, what sort of amount of water has got in?
 

maxf

New member
I do the same with mine, then the battery's started getting damp after wet trips, I couldn't figure out why for a while then noticed a small hairline crack on the battery box gland where it had been bashed.

Demoted that helmet and light to digging only (usually dryish)
Bought another duo and helmet for normal trips and shallow short dives

Keep another helmet with dive torches on for dives

I pick the most appropriate one for the trip
 
Pitlamp said:
Matt - you said you open it up and let it dry after a dive. Does it actually get water in or is that just precautionary? If it does leak, what sort of amount of water has got in?

There never seems to be any in the head itself, but there is often some water in the battery box (predominantly small droplets on the walls and some on the batteries) though not  alarge amount, the terminals are not sitting in a puddle or anything.  I am relatively fastidious about cleaning the battery box o-ring after mucky trips and giving it a bit of a wipe with silicone grease.
 
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