Polymer Crosslink
Hardener:base ratio for epoxy and other two-part resin systems.
How to use this tool
Work out exactly how much resin and hardener to weigh out for a two-part system so it cures properly. Off-ratio mixing leaves a soft or brittle part, so get the numbers right before you pour.
What to enter
- Ratio / phr tab: enter the mix as a ratio (resin parts : hardener parts) or as phr (parts hardener per 100 resin), whichever the data sheet quotes.
- Ratio basis: whether that ratio is by weight or by volume.
- I'm measuring by: start from a known amount of resin, or from a target total batch.
- Amount: the resin quantity or total batch you want, in g or mL.
Reading the result
You get the resin, hardener and total batch amounts to weigh or measure, plus the ratio restated. Weigh by mass for accuracy, especially on small batches.
Worked example
A 2 : 1 by-weight epoxy, measuring from 100 g of resin, needs 50 g of hardener for a 150 g total batch.
Mix
The three figures are the resin, hardener and total batch to weigh or measure out, with the ratio restated below in your chosen basis (weight or volume). Weigh by mass on a scale for accuracy, volume is harder to hit, especially on small batches, and mix the full amounts thoroughly, since an off-ratio or under-mixed pour cures soft, tacky or brittle.
Mixing two-part systems
Two-part resins cure at a fixed ratio set by the chemistry. This tool works either from a manufacturer ratio (by weight or volume) or from phr (parts hardener per hundred resin). Off-ratio mixing leaves unreacted resin or hardener and gives a soft, tacky or brittle cure, measure by mass for accuracy, especially below ~100 g batches.
Sources
- Epoxy/PU technical data sheets; phr convention (parts per hundred resin).