Epoxies, acrylics and polyurethanes give off heat as they cure. In a thin bondline the heat escapes, but in a mixing cup or a thick bead it builds up, cutting pot life, causing bubbles or cracks, and in extreme cases smoking and charring the adhesive. Fast acrylics in thick sections can blister from their own exotherm. Large pours use slow hardeners or are split into layers.
Don't leave the mixed epoxy in the cup, the exotherm will cook it and it'll be smoking in ten minutes.
Data sheet pot life is measured on a fixed mass; double the batch and the pot life gets shorter, not longer.
Also heard as
- exothermic reaction
- exothermic heat
Related terms
Pot life
How long a mixed batch of two-part adhesive stays usable before it thickens too much to apply.
Kick
To gel or cure suddenly, as in a resin kicking in the cup or a CA kicking with accelerator.
Structural acrylic
A fast-curing two-part methacrylate adhesive that bonds metals, plastics and composites with little surface prep.
Two-part
Describing an adhesive supplied as a resin and a hardener that start curing only once mixed.