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Woodworking Math

Hardwax oil

Hardwax oils combine oils and waxes in one finish. Osmo says Polyx-Oil is based on plant oils and waxes (sunflower, soya and thistle oils, carnauba and candelilla waxes) and goes on in two thin coats, 8–10 hours apart, without thinning.

Rubio Monocoat Oil Plus 2C is a two-part oil mixed about 3 to 1 and applied in a single coat, with all excess removed within 15 minutes. Rubio says the surface can be used after 24–36 hours, is 80 % cured in 2 days, and can be cleaned with water after 5 days. Osmo says its dry finish meets EN 71-3, the European toy-safety standard.

Hardwax oils, by their makers

Hardwax oils: recoat across makers

Only one maker’s sheet so far, so no class value: see its own figure below.

Hardwax oils: coverage across makers

1,304 sq ft/gal

span 978–2,037 sq ft/gal, per coat

Only two sources publish this: Osmo and Rubio Monocoat

Hardwax oils, by their makers; each row is its maker's own figure at the conditions it states
ProductTouch-dryRecoatUseFull cureCoverageThinning and notes
Osmo Polyx-Oil Original

One source: Osmo, the maker of that product

—8–10 h——24 m² per litreThinning: Do not thin.Plant oils and waxes; two thin coats on bare wood, one to renew.
Rubio Monocoat Oil Plus 2C

One source: Rubio Monocoat, the maker of that product

——remove all excess within 15 minutes per zone24–36 huse (80 % cured in 2 days)—30–50 m² per litreThinning: Do not dilute.Two-part: mix about 3 parts A to 1 part B; one coat; clean with water and soap after 5 days.

Compared with other finishes

Work it out for your project

Times are the makers' own at the temperature and humidity they name, and several of them say cooler, damper conditions slow their finishes. For how much to buy, the finish coverage calculator uses these same coverage figures. Every finish side by side: the finish dry time chart. What the federal rules say about finishes and food: food-contact finishes.

Elsewhere in finishing: shellac and the shellac cut calculator; for repairs before the finish, wood filler vs wood putty; and for the glue-up, wood glue types.

Sources

  1. Osmo, Polyx-Oil Original (3011, 3032, 3062) product information (UK distributor copy), read 2026-11-07.
  2. Rubio Monocoat, Oil Plus 2C technical data sheet (EN), read 2026-11-07.

How the tags work: How we source every number.