Stupidly locked my case

[Schwob]

After I closed the equalize pipe by epoxy in my Panasonic DMW-MCTZ3 (this pipe is under lock handle, covered by sealing on lock handle - may be you have the same?), it starts to be difficult to open back door.
I use lock handle as support and as a lever. I`m set lock handle to back door flange (not from back side, but from lock side), and with extra power to lock handle is opening back door...

another way is:
you have front glass, attached by ten screws. You can take off this screws and try to open front glass.
But be very carefully with front glass sealing.

Third, most stupid, but possible way - to find strong box (tank, steel sphere, pressure cooker or any another strong sealed container), and 10 m hose (30ft) 3-5mm diameter. Attach this pipe to the box, open camera case lock handle, put your case in to the box, fill this box AND pipe full of water (without air bubbles) and drop one of the pipe ends down (from third floor of the building).
Water in the pipe make strong vacuum inside the pipe and the box, and your camera case will be opened easy just in the box.
Later you will need just to dry it.

I like that third way...

 

[bvanant]

It is not clear that heating it will be easy. At 4000 m the air pressure is about 475 mm Hg. At Sea level it is 760 mm so the decrease is about a factor of 1.6. If we assume that the case holds 1 liter then using the ideal gas law we calculate (P=0.625 atmospheres, V= 1 liter, R= 0.0821, T=298 K) that there are about 0.026 moles of gas in the case. To get the case to 1 atmosphere we will need to raise the temperature to about 200C (477K). That is probably above the Tg of the plastic in the case. Of course you don't need to get it that hot. I would take it up to as high as I could go then heat it up until I could open it up.

Cheers
Bill

 

[tursiops]

It is not clear that heating it will be easy. At 4000 m the air pressure is about 475 mm Hg. At Sea level it is 760 mm so the decrease is about a factor of 1.6. If we assume that the case holds 1 liter then using the ideal gas law we calculate (P=0.625 atmospheres, V= 1 liter, R= 0.0821, T=298 K) that there are about 0.026 moles of gas in the case. To get the case to 1 atmosphere we will need to raise the temperature to about 200C (477K). That is probably above the Tg of the plastic in the case. Of course you don't need to get it that hot. I would take it up to as high as I could go then heat it up until I could open it up.

Cheers
Bill

Thanks for making this calculation. I was going to do it when the idea was first mentioned, but got distracted.

 

[Chris Ross]

any of these ideas for prying will damage the case, You need to oppose and apply that 30 kg or so of closing force in a small area where to tool is pressing down on one side of the case and pushing up on the other side of the case. You may get the case open at the cost of damage to the casing possibly compromising the sealing surface. Same with sliding the front glass there is a significant force pressing down upon that glass. Same with heating it up, 200deg C is a bit on the warm side for the plastics involved.

The only safe course is to go back to or close to 4000m. If you can't quite get to 4000m then the temperature needed is liinear, I estimated 188 C at sea level assuming case was closed at 20 C. You would need about 90 C at 2000m and about 45 C at at 3000m give or take a little.

 

[northernone]

I've successfully used a tightly jetted HP air source on an oring as described up thread to recover a housing locked at 2000m.

I wanted to build a vacuum chamber to solve the issue but I had a scuba tank and hoses and no suitable chamber on hand.

Taking a drive back up the hill is easy too though.

Cameron

 

[АлександрД]

I forgot about very usefull thing in chemistry:Desiccator - Wikipedia
250mm Vacuum Desiccator Jar Laboratory Dessicator Dryer,Schools Laboratory Vacuum Drying Storage Desiccator Glass,Desiccator Jar-in Lab Drying Equipment from Office & School Supplies on Aliexpress.com | Alibaba Group

and vacuum pump from air conditioner service:
https://www.amazon.com/ZENY-Electric-Refrigerant-Conditioner-Conditioning/dp/B017JNZT3S

 

[Dan]

It is not clear that heating it will be easy. At 4000 m the air pressure is about 475 mm Hg. At Sea level it is 760 mm so the decrease is about a factor of 1.6. If we assume that the case holds 1 liter then using the ideal gas law we calculate (P=0.625 atmospheres, V= 1 liter, R= 0.0821, T=298 K) that there are about 0.026 moles of gas in the case. To get the case to 1 atmosphere we will need to raise the temperature to about 200C (477K). That is probably above the Tg of the plastic in the case. Of course you don't need to get it that hot. I would take it up to as high as I could go then heat it up until I could open it up.

Cheers
Bill

I think if you put the case in (60-70C) hot water long enough (~ 30 min) to warm & expand the air inside the case, the vacuum pressure would be less enough to pry open the split face of the camera cover by the sharp edge of a knife.

 

[lionfish-eater]

A suction cup grip handle like glass installers use might help to pull on the back rather than prying.

 

[Chris Ross]

I think if you put the case in (60-70C) hot water long enough (~ 30 min) to warm & expand the air inside the case, the vacuum pressure would be less enough to pry open the split face of the camera cover by the sharp edge of a knife.

You can calculate the pressure, it will increase from about 0.65 bar to about 0.76 bar at 70 C. so still a force of about 20 kg holding the housing closed, assuming an area of about 75mm x 100mm that the pressure is acting upon.

 

[Dan]

You can calculate the pressure, it will increase from about 0.65 bar to about 0.76 bar at 70 C. so still a force of about 20 kg holding the housing closed, assuming an area of about 75mm x 100mm that the pressure is acting upon.

You'll be amazed on how much prying force of a sharp-edged blade can act along the 75mm slit.