Beads of a fixed diameter, often 0.1 to 0.5 mm, stop clamping pressure from squeezing a joint thinner than the bead size. A few percent by weight is enough. Some structural adhesives are sold with beads already in them, and production lines add them where fixtures cannot control the gap.
Add the 250 micron spacer beads to the batch, we keep squeezing the bondline to nothing.
Also heard as
- glass beads
- bondline control beads
Related terms
Bondline
The layer of adhesive between two bonded parts, and in shop talk the thickness of that layer.
Starved joint
A joint left short of adhesive, with bare patches or voids where the glue soaked in, squeezed out or never reached.
Squeeze-out
The excess adhesive that oozes out along the joint edges at clamp-up, read as proof the joint is full.
Gap filling
The ability of an adhesive to bond parts with a loose or uneven fit and still cure fully across the gap.