Pils and plastic kegs

[crasher600]

Hi all. merry xmas and all that mallarky. Im about 30 kit brews into homebrewing now and have picked up many useful advice from this forum. one of the things i have read here is that lagers dont work well in plastic kegs as they cant hold a high enough pressure for correct carbonation so as i cant afford to bin ny 4 kegs and buy cornies i have been putting all of my pils etc into bottles. this is obviuosly a bit of a pain in the **** so i was wondering if i replaced my pressure release valve with a straight inlet valve could i acheive decnt carbonation if i stick to the correct amount of priming sugars. I suspect that pressure reliefs are fitted for a reason but i have used cola pet bottles for my lagers also and these dont seem to have a problem with pressure and the plastic a king keg is made from looks a damn site thicker to me.
or am i just being a damn site thicker myself ?

 

[brobin]

Hi Crasher600

As I understand it there is a very good reason for having a pressure release valve on a plastic barrel. Infact one of my barrels actualy has printed on it "Maximum pressure 12psi".

Anything above that will at best cause the barrel to bulge and at worst split / explode as the volume of gas inside is far, far greater than in a PET bottle and so has far more barrel to exert this pressure on. (someone into physic will be able to explain this far better than I can)

This is why we use corny kegs as they are rated at up to 100psi - More than enough to force carbonate a lager.

In short - Don't push a plastic keg to more than 12psi as it can't take it!

 

[crasher600]

That answers my question nicely. many thanks