A friend of mine is looking at installing a small metal container, similar to this….

https://www.amazon.co.uk/CAMTOA-Survival-Container-Capsule-Emergency/dp/B016WHJY0Q/ref=sr_1_6?s=sports&ie=UTF8&qid=1501529597&sr=1-6&keywords=waterproof+capsule

…pretty much in seawater. What material would be best to use to prevent corrosion of the thread? Would copper anti-seize help?

Aluminium will last no time at all in seawater.

Stainless or titanium.

316 Stainless , minimum.

Corten steel mate.

Make it outa dat.

And I’d be amazed if that seal withstands any immersion.

Edit: In fact if he wants to do it on the cheap, go to a plumbers merchant. Plastic fittings, won’t corrode. Will withstand a bar or two of pressure.

Cupronickel

Why?

CRA725 for blowing the budget

Why not make one from plastic waste pipe you can get screw on sealed end fittings so should be watertight.

PVC piping can work well, but frankly if he only wants one that small… buy a cheap peli light, strip out the innards and store stuff in the battery compartment.

Great insight, cheers all.

Its for a geocache, which is to be located in a very inaccessible bit of coastline. So I guess notionally we’re looking at 5yrs+ life, with zero maintenance. But has to remain serviceable over this period.

Initially we were looking at aluminium, purely because suitable size containers are common in that.

Can’t find anything ready made in 316, or the other exotic metals.

Will investigate plumbing bits, hadn’t considered them up till now, but that could be the ideal solution.

Will it be getting submersed or just have to withstand sea spray?

why not just use a plastic film canister like all the other c:geo people?

Waste pipe, two solvent weld couplers and two solvent weld access plugs.

You’ll get change from £12 (plus solvent) and you’ll be left with 2.7m of pipe, 3 couplers and 3 access plugs 🙂

Black fittings to make it hard to find, white to make it easy!

Its going to be mounted about 8ft above high water, but on an exposed rock, in often rough water. So I guess not technically submerged, but will get a real hammering on the spray/wave front.

And tell us what it’s called so one of us maybe ftf!

Happy to share the cache info when it’s published.

The owner is thinking its never going to be found. I think it’s going to be found about twice a year. We’d both be happy for it to be found more often, so happy for everyone to tussle for FTF. And longer term, will be interesting to see how often it gets found!

I wont give too much away here just now, in case we never quite manage to get it published. But if all goes to plan, should be going live in early September.

Drop me a mail. I might be able to help out. It’s the day job…

Can’t find anything ready made in 316 ?

https://www.asap-supplies.com/fittings-valves-strainers/strainers-and-spares/strainers/base-mounted-water-strainer-422005

Prob not the cheapest option.

Vongassit, genuine LOL. I should have also mentioned that when installing this, the cache owner has to swim 50m with it to the mounting site!

As a Project Manager in coastal construction, plastic or plastic. Unless you can get some thick cast iron like Brighton pier. Any metal will be destroyed in short order unless it’s seriously sturdy with corrosion protection and preferably regular inspection.

UV stable plastic will be cheap and work.

custom divers/narced at 90 do canisters that are rated deep…..

This might be quick/cheap; http://www.narkedat90.com/storage_tude_p/nantube.htm

In the splash zone there will be times when seawater dries out on your container and becomes more concentrated. For that reason cheaply replaceable plastic becomes a better bet. So long as the UV light doesn’t destroy it.

if you’re using metal, then Cupronickel is about as good as it gets.
The seawater cooling systems on ships are usually made of this.

Titanium is arguably better, but the price would be prohibitive.

For the application you’re talking about, I’m also thinking plastic would be your best bet – ideally something which is reasonably good in daylight/UV light.

Peli case?

Thanks all. Definitely given us lots to think about, and helped confirm that aluminium is not the way to go.

I really don’t want to get all elf’n’safety-gawn-mad but it sounds like it might be moderately perilous for the budding geocacher to reach?

Made me wonder – are there any common standards of where caches should be placed to avoid putting people at (an acceptable level of) risk when trying to find them?

I wouldn’t want to be sued if someone got injured/drowned trying to find one I had placed in an exposed location like you seem to be describing… I guess the question of it being ‘at your own risk’ is a muddy one. I could foresee someone arguing that if it was placed in a particular spot it was some kind of invitation/implication that it was safe to retrieve…

Anyone more knowledgable care to weigh in?

I’ve had potential cache locations rejected due the location being unsuitable IE potential problems with safety and access. Once you submit a new cache it has to be approved by “someone”, prior to it going live on the Groundspeak website. Who does this I’ve no idea. Presumably someone with local knowledge. I don’t know how subjective this process is. The caches I’ve placed have hence all been close to ground level.