Renner M402 Hardener for 643 Water Primer 250ml
Renner YC-M402 is the hardener for the YL-M643 water-based primer — the component that turns a 1K primer into a two-pack system.
What catalysing gives you
- A harder, more durable film, noticeably more resistant to handling, cleaning and knocks.
- Less grain raise on MDF, so machined edges come back smoother after the first coat and you sand away less of what you just applied.
- The performance kitchen and bathroom furniture needs, where the finish faces moisture and constant contact rather than sitting on a wall.
Why the label may mention solvent
This one catches people out, so it's worth stating plainly.
Hardeners for water-based two-pack systems are polyisocyanates, and polyisocyanates are carried in a co-solvent to hold them at a workable viscosity. The labelling reflects what is in the tin, as it must.
It does not mean you're working in a solvent system. Added to YL-M643 at the correct ratio, the mixed and applied coating is water-based, and equipment cleans down with water.
Mixing
Add at the ratio given on the primer's data sheet, mix thoroughly, and work inside the pot life. Once catalysed the clock runs whether you're spraying or not — only catalyse what you'll actually use.
Handling
Contains isocyanates, which are respiratory sensitisers. Work to the current safety data sheet and your own risk assessment: isocyanate-containing two-pack products carry specific respiratory protection requirements for spray application, and a cartridge mask is not always sufficient.
Match the hardener to the primer
M402 pairs with M643. The M641 primer takes M404 instead, and the two are not interchangeable.
250ml. Clean equipment immediately after use.
- Free delivery on orders over €85 (Ireland)
- Orders placed before 12pm ship same day
- Click & collect available at Ballymount, Dublin
- Tinted paint is non-returnable once mixed
