On Saturday, June 9, 2018 at 8:22:46 PM UTC-7, AS wrote:
On Saturday, June 9, 2018 at 9:21:30 PM UTC-4, Steve Koerner wrote:
Uh-oh, someone doesn't understand how gas springs work:

I do - I used to design similar devices....
Uli
'AS'

Well Uli let's talk gas springs for a moment...

If you actually did understand how gas springs work - the everyday gas springs used for car tailgates and glider canopies and Wing Riggers and Cobra trailers - then you would know what a silly suggestion that was. Gas springs already have a controlled leak across the piston. That is what establishes their wonderful damping property. Once stopped, there is no pressure differential across the piston at all. The nominal force produced by a gas spring does not relate to pressure across the area of it's piston (as is the case for a pneumatic drive cylinder); the gas spring force arises from the pressure exerted across the cross-sectional area of the rod itself.

Anyway, don't feel too bad about getting this wrong. I did a google search so that I could provide a link for you. Amazingly, virtually every little story that came up about how gas springs work on the internet was also wrong -- including the wikipedia article on gas springs and a bunch of youtubes on the subject. It wasn't until I downloaded a lengthy manufacturers catalog that I came upon actual sound science that tells the story correctly:
http://pdf.directindustry.com/pdf/di...57-175377.html

So back to the original poster's issue: You do not need to worry about pressure leaked to the wrong side of the piston and holding the clamshell down.. That is a red herring of the highest order.