According to GOST (TU) 6-10-1263-77 transparent liquid without sediment
It is included in the set of epoxy enamels and primers, as it serves as an accelerator for drying (for curing).
How much hardener is needed per 1 liter of paint depends on the brand of enamel. The calculation is from (2.0+/-0.2) grams to (5.0+/-0.2) g per (100.0+/-0.2) kg of base paint material.
For example, for paint EP-525 in the kit will go 1.4 kg. hardener 1
The composition of hardener 1 includes 50% diluted hexamethylenediamine dissolved in ethanol or isopropane.