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Hey guys,

 

Proud owner of a S&S DX-2G with YS-01 strobe, which have both served me well for years. After all this time, I've noticed though, that the O-Rings on the arms (S&S arm 7) are starting to get very brittle. Just to be clear: I am talking about the thick O-Rings that help stabilize the joints of the arm in a certain position.

 

Now I'd like to replace those sooner rather than later, and preferably before I get to Bali in August. Does anyone have any idea, where I might be able to purchase a set of those 4 O-Rings? I've gone through plenty of sites and online retailers, but they all only seem to offer replacement O-Rings for the strobe itself, not for the arm though...

 

Any tips or advice welcome! Cheers for the help :)

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i bought a 100 off ebay for ULCS arms about a year ago. Check ebay out.

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can you remove one and measure it or at least take a picture of it next to a good mm scale?

thanks

Bill

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Ha, now there's an idea!

 

I did manage to take one off without ripping it. I measured 28mm in diameter with a strength (thickness) of 5 mm. The ones you linked on amazon seem a little bit smaller, with a diameter of 24mm and a strength of 3,5mm. But based on my measurements, I'll see what I can find online.

 

Thanks, you have been very helpful! :)

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Edited by Zyndell

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@Zyndell just out of curiosity, did the replacement o rings work for your arms? I’m looking around for some for my Nauticam arms, but I’m not sure they are the exact same size. 

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Nautical actually sells replacement o-rings. I replaced all mine on cheap arms with Nauticam ones so that they match the ones on my Nauticam Tray. Found they were different which made the clamp work less well at the lowest joint. Try not to mix and match o-rings. 

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27 minutes ago, Driftc said:

@Zyndell just out of curiosity, did the replacement o rings work for your arms? I’m looking around for some for my Nauticam arms, but I’m not sure they are the exact same size. 

The Nauticam replacement ones are about $12:00 for a pack of 10 at the UW photo retailers.  They seem to be silicone o-rings and seem to last quite well.

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@ChrisRoss I saw that replacements are offered, but I’m actually interested in trying a few variations out to see if gripping power is higher for splitshot/ stream environments where portions of the arms are out of the water for periods of time. I also tend to carry my housings for long distances hiking up and down rivers, and notice that there is some slipping of the arms while moving between pools.
 

***I’ll note that this is a very atypical use of this gear, and have never had a problem while snorkeling or scuba diving with Nauticam arms/clamps/O-rings. 
 

From what I can tell the O-rings on the Nauticam are 4mm wide, 17mm ID, 24mm OD silicon which are stretched to 28mm over the ball joint. I’m curious to try out ones made of Viton fluroelastomer due to the hardness properties— but don’t have any idea if that will make a difference. Has anyone played around with different materials, cross section shape, and/or sizes for this purpose?

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1 hour ago, Driftc said:

@ChrisRoss I saw that replacements are offered, but I’m actually interested in trying a few variations out to see if gripping power is higher for splitshot/ stream environments where portions of the arms are out of the water for periods of time. I also tend to carry my housings for long distances hiking up and down rivers, and notice that there is some slipping of the arms while moving between pools.
 

***I’ll note that this is a very atypical use of this gear, and have never had a problem while snorkeling or scuba diving with Nauticam arms/clamps/O-rings. 
 

From what I can tell the O-rings on the Nauticam are 4mm wide, 17mm ID, 24mm OD silicon which are stretched to 28mm over the ball joint. I’m curious to try out ones made of Viton fluroelastomer due to the hardness properties— but don’t have any idea if that will make a difference. Has anyone played around with different materials, cross section shape, and/or sizes for this purpose?

Hardness is one property, I'm not sure how much it would influence clamping force.  There does not seem to be a lot around on differing coefficients of friction between different rubbers, which  I think may be the biggest consideration.  This links talks about properties of rubber:  https://www.allsealsinc.com/Material-Selecting-Rubber-Compounds.html

it notes fluro-silicon and silicone exhibit poor frictional properties so it might be better at holding the arms in place but may not slide as smoothly.  You are relying on the coefficient of friction increasing the force needed to move the joint.  Viton(flurocarbon)  is rated slightly better at dynamic service so might slide a little better which is probably not what you want. 

I'm wondering if adding something like a big hair elastic (scrunchy)  over the arms to prevent them flopping might be a better approach? And moving the lanyard to the middle clamp so the housing hangs off the arms, rather than clipping to the tray handes?  I'm quite aware of arms tendency to flop around out of the water - I experience the issues on shore dives around home.

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I have probably tried all of the easily available rubber compositions for ball o-rings ranging from nitrile through fluorosilicone and silicone. For me the best at keeping arms put is the standard orange silicone from McMaster or the o-ring store. In my hands at least softer is better for keeping arms in place, but you need to unscrew the clamp a bit to get them to slide easily.

Bill

 

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