I had a large bulk tanker trucking company stop in and have us look over a few of their pneumatic bulk trailers.  They are all aluminum and need some crack and small hole repairs.  The operating pressure during unloading is 10-12 psi.  The frame cracks looked like no problem, but the actual tank repairs themselves will require a few patch plates and more work.  Have any of you repaired such a trailer, and is there too much liability in repairing the tank itself for us to even consider it?  We pull a lot of semi trailers in the shop currently, but nothing on a "pressure vessel" type of rig.  I have already contacted the OEM looking for a qualified repair procedure, but have not received anything yet.
Thanks for the info!
Mark