Arri Suction cups

B

bob'slaststand

Member
I’ve recently picked up some pump suction cups off eBay. I then tried fixing them to a surface and left them there, after a while they lost the pressure and came off but not having owned these cup new or second hand before I was at a lost to know if that’s fine or if they are not working as they should? Do these cups deteriorate over time, holding for a shorter and shorter period or do they not wear in this way? Is there other ways they can fail over time or other ways to check what condition they are in?
 
They lose suction over time. Is there a red line where you pump the cup with your thumb? You should have enough suction if you can't see the line. It'll show itself every now and then, which means it'll need a few more pumps.

If it doesn't work this way I'd be cautious. You can do your own tests, mount some weights etc. instead of expensive film equipment.
 
I presumed that the red line meant that the pressure was too low. They all pump so the red line is gone. I’ve pumped them all up on the wall to time how long they last before the line comes back.
 
All depends on the surface flatness an smoothness, glass, shiny painted metal, etc. are best. You can normally get a little extra out of them if you clean the surface first, and then maybe a small amount of water which helps the seal.
 
What I'm trying to figure out is how to check if they have deteriorated with age and use and by how much? Some things are the same second-hand as new and some things have a life expectancy so buying them second-hand is a bad idea. I’m trying to understand where on that spectrum these fall as I’ve not owned them before.
 
I guess if you can hide the red line they are fine - that is what the red line is for.

One may (generally) consider gripping in such a manner that an individual suction cup failure becomes a non catastrophic event...

ie double up your system with ratchet straps.

S
 
Regardless of how long any of these cups hold, gear should always be safetied for this kind of use...if there's no grip dept. on your shoot, figuring out a system is up to you, and the how will change with every different scenario....also, safety from at least tow sides, so in case of an accidental release, the gear can't swing and bang around (sustaining damage) but simply drops slightly and can be secured again.
 
I appreciate the advice on rigging but working out whether the kit is still fit for purpose is my first concern. I tested them without load over night and they were all still attached in the morning after roughly 7 hours. One pump looked like it had not moved, one had moved a bit and the third had the red line just visible.

I stripped them down, gave them a clean, checked all the rubber seals inside and checked the plastic pump tubes for wear or dirt, they all looked in very good condition. The only place I can think of that they could be loosing pressure is where the pump connects to the rubber plate.

I tested them with a 2Kg load each while I was out for about 4 hours and they all held with the same one showing the red line when I got home.

I hung 17Kg, which is all the weights I have here, and they all carried it without any problem, I suspect they could hold a lot more.

Unless someone here has something else to say I’m going to say their fine. I marked the one that tends to loose pressure faster and might see if I can find some rubber sealant if I ever get the time but for any use under a few hours I’d trust them all.
 
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