Prepreg stored at -18°C has a shelf life. But the moment it leaves the freezer, out-life starts ticking.
Common failure we see from new buyers:
Roll thawed in open air → condensation → steam voids in autoclave
Ply sits on cutting table 6 hours → resin advances → poor flow, dry spots
"It looked black and fine" → laminate fails open-hole compression
Rule we run in-house:
Frozen shelf life: 12–24 months depending on system
Room-temp out-life: 30–60 days typical, sometimes less
Thaw sealed 24h before opening
Log every roll: in/out time, batch number, used-on PO
If your supplier can't show out-life tracking, you're not buying aerospace-grade prepreg process. You're buying hope.
