Action Camera Mounts that suck (and those that don't)

[Paul White]

I use an my action cameras for capturing my sailing activities so they are exposed to seawater which as we all know is very corrosive to mild steel. You might think that the mounts designed for action cameras should be able to cope with seawater since they are often advertised showing underwater use or being used when swimming or attached to a surfboard but some of the mounts will corrode really quickly because they don't use 316 Stainless Steel (the only stainless which is designated for a marine environment).

The mounts of shame (they may have some mounts in their range which don't use metal but those that do are to be avoided)
Kaiser Bass
SP Gadgets

The mounts of dubious steel
RAM Mounts (some screws and bolts seem to be zinc plated not stainless)

The mounts of stainless steel
Go Pro ($$$)
Sony ($)

Other sources of 316 stainless steel mounts appreciated.

 

[Nigel]

Most of the cheaper mounts are fine if you replace the cheap steel bolts by stainless steel bolts, or aluminium bolts if you want to save weight. Nuts and bolts made from marine grade stainless are easily available on ebay etc. Most of the mounts use standard metric sized bolts, often M5 threads.

Only ones that really cause problems are where the plastic thumb grip is moulded on to the bolt, but the cheaper ones tend to have a separate bolt that goes through the grip, and you don't always need the grip - you can use a spanner and nylock nuts if it is a semi-permanent installation.

 

[Paul White]

True but it sort of defeats the object and adds to the cost if you have to replace all the nuts and bolts.

I have one camera mounted on a pole suctioned to the stern which is permanent but the one on the carbon bowsprit I remove every time as it would damage the sail if I put it away with the mount still attached.

 

[SawMaster]

I'm not certain but brass might also be a viable option. According to some folks online who seem to be knowledgeable about things, a lot of the stainless hardware from China isn't of the claimed grade, and many of the steels coming from there are equally bad, having improper metal ratios and impure content including some "food grade" stainless which has heavy metals in it When you're buying from a reseller as will be the case with hardware, the odds are that they are buying the cheapest they can which is going to be from China. China can produce some very good products, but not all are like that.

Marine and aircraft grade hardware is never cheap, but with your life possibly riding on it I wouldn't bemoan a little extra cost just to be sure.

Phil

 

[Matt_V939]

Marine grade stainless stell (like 316 or even better 316L) is on a different level of "basic" stainless steel (e.g. 304).
There is a reason why salt spray chamber test is performed, that's among the WORST possible corrosive conditions (even worse than fully submerged in salt water being exposed to spray in marine/shore environment).
https://www.assda.asn.au/technical-...0-corrosion-resistance-in-marine-environments
https://en.wikipedia.org/wiki/Marine_grade_stainless

 

[Paul White]

Marine 316 grade costs around 33-45% more than standard 304 grade stainless per tonne depending on your location. (source: meps.co.uk MEPS (International) Ltd - Independent Steel Industry Analysts, Steel Prices, Forecasts, News, Reports).

I would willingly pay 30-45% more to be able to buy something that isn't going to disintegrate in a few months, even though I rinse all my gear with fresh water after sailing.

It's not just the mounts that are at fault, some budget cameras use zinc plated mild steel screws (I'm looking at you Hangzhou Xiongmai Technology Co.,Ltd aka XM aka Yuncooltech). And even some of the non-budget cameras (e.g. Drift) use 304 stainless for the hinges of their waterproof cases which are almost impossible to keep from rusting.

I have seen brass fittings used on some cameras (mainly for 1/4" tripod mount holes) but not for screw fittings as its quite a soft metal.

 

[Matt_V939]

Marine 316 grade costs around 33-45% more than standard 304 grade stainless per tonne depending on your location. (source: meps.co.uk MEPS (International) Ltd - Independent Steel Industry Analysts, Steel Prices, Forecasts, News, Reports).
...

I'd think that raw material cost doesn't turn proportionallu into final cost , production and distribution costs will account for a bigger portion on the final price. Demand for topspec material is not as big as for 304, which means probably you'll pay way more than 30%( to material difference only).

EDIT: you might try a sacrificial anode strategy, bolting or connecting an additional zinc or aluminum nut....even if this works better for fully submerged parts, you should fight agains pitting corrorion instead
http://www.trumbull-mfg.com/products/products-for-corrosive-soils/zinc-anode-caps/

 

[Nigel]

The difference in cost between marine grade stainless steel nuts (A4) and bolts and normal stainless steel ones (A2) is normally very small, the choice between the two depends on if you need the strength of the normal ones or the ability to cope with salt water for years at a time, the marine grade ones are a fair amount weaker. I've never experienced any corrosion on the normal ones, although I don't often put them in the sea, I do use some on the mud guards on the car which in a UK winter are exposed to road salt and generally nasty conditions. A2 and A4 bolts are normally a straight swap for normal 8.8 steel bolts, available in all the common metric sizes.

Brass will suffer from surface corrosion, which on small threads could result in them seizing up a bit, stainless is much better. Aluminium seems to be good too, although it is not as strong and will eventually disappear in sea water, aluminium bolts are used for greenhouses which are constantly exposed to the weather and still last for many decades.