Flash tape in a vacuum bag stack
In composite curing, flash tape is the high temperature tape that holds the vacuum bag to the tool edge and seals the bag perimeter. It has to stick to a release treated mould, hold vacuum through a ramp to 180 C, and peel away without tearing the bag or leaving adhesive on the tool surface.
What the bag stack needs
High temp bagging tape needs a high tack silicone adhesive, a backing that stays flexible rather than going brittle as it heats, and a width that covers the tool flange with a clean margin. A narrow tape on a wide flange means two runs and a seam, and a seam is where the leak starts.
- A high tack silicone adhesive that holds under vacuum at cure temperature.
- A backing that stays flexible rather than going brittle as it heats.
- A width that covers the tool flange with a clean margin.
- Consistent roll quality, because one leak stops the whole cure.
Avoiding leaks and tool contamination
Clean the flange, apply with a firm roller, and keep pleats out of the seal line. A single lifted section shows as a vacuum drop during the ramp, usually when the part is too far along to rescue. On removal, pull the tape back on itself at a low angle while the tool is still warm.
For a shop running several tools, specify one composite curing tape and one width per flange size, and record which cure cycle each roll has been approved for. A vacuum bag sealant tape alternative that changes between batches makes every leak harder to diagnose.
