Hi Debi,
Yes even 5 ton would be plenty for me
- I usually make white mold ripened soft cheeses and only recently attempted a couple of Tommes (but they don't seems to need a lot of weight). I have made some alpine cheeses that require a fair amount of pressure, but using a 4" mold still keeps it in check.
I actually posted this more as a suggestion for somebody who is making cheddar or other cheeses in large molds, requiring several tons of weight. And for somebody who wants to press upward of 10psi, I think this might still work - especially for a hobby cheese maker. Who ever leaves their cheese unattended anyhow (at least I don't). I constantly monitor it and flip it for the fist couple of hours - by the time you apply full force and you go to bed, I think the cheese is mostly compacted and you don't loose that much pressure over the final 5+ hours of pressing. And these shop presses are cheep!
All that being said, I did come across a listing for a pneumatic cylinder on ebay with a 100mm bore for only $25. If you use an 8 inch mold and 200psi air pressure you end up with approx 48psi pressure on your cheese - or the equivalent of balancing 2400 lbs on your cheese! That's probably more than enough for any cheese I plan on making ... ever!
So, yes, air it is - not only because it can provide more than enough pressure needed, but also because it is more consistent (as Wayne points out).
I just hope I don't ever get my fingers caught in there somewhere