From: "@frank.net   
      
   On 3/30/2016 11:14 AM, Peter Fairbrother wrote:   
   > I use a 5% solution of KOH (for Brashear silvering) from time to time,   
   > frequently enough so that I don't want to make it up every time, but not   
   > so frequently that a bottle gets used up fast.   
   >   
   > My problem is what to store it in. Glass is out of the question, as is   
   > PET. PP maybe, but does CO2 diffuse through it?   
   >   
   >   
   > Any suggestions?   
   >   
   > Ta,   
   >   
   > --Peter Fairbrother   
      
   Gas diffuses through all plastics but at different rates.  I know PE is   
   probably the worse and polyvinylidene chloride one of the best. The rate   
   difference is about 1000/1 for these two resins. You can also make good   
   barrier films of PE covering a polyethylene/vinyl alcohol base.   
   Thickness is also a factor and I think a sturdy poly-olefin bottle   
   should be OK for at least a few weeks storage.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)