Common ratios are 1:1, 2:1, 4:1 and 10:1 by volume, matched to cartridge sizes and pump settings. Epoxies and polyurethanes depend on the right balance of reactive groups, so straying more than a few percent leaves unreacted material, lower Tg and softer, weaker bonds. Acrylics with 10:1 initiator ratios tolerate more error. Ratio checks on meter-mix machines are routine quality steps.
Mix ratio check on the meter-mix came out 1.8 to 1, it's supposed to be 2 to 1. Shut it down.
A ratio given by volume is not the same as by weight unless both parts have the same density; check which one the data sheet uses before hand-mixing on a scale.
Also heard as
- ratio
- mixing ratio
Related terms
Two-part
Describing an adhesive supplied as a resin and a hardener that start curing only once mixed.
Off-ratio
Describing a two-part adhesive dispensed with the wrong proportion of resin to hardener.
Meter-mix
Dispensing equipment that pumps two adhesive components from bulk containers in a set ratio and mixes them on demand.
Marbling
Swirls and streaks of separate colors in a two-part adhesive that show it has not mixed thoroughly.