Paint notes

Finish Coat RAL 6003 (6 litre batch)

This recipe is a solid, traditional-style linseed oil paint formulation and should work well overall for an exterior log cabin garage on a mechanically keyed (abraded) existing finish plus bare wood areas. It uses classic, durable, breathable ingredients that align with historical exterior wood paints (like Swedish or barn-style linseed paints). These paints penetrate wood, flex with seasonal movement, resist peeling/flaking better than modern acrylics, and allow moisture vapour to escape which is critical to avoid rotting. In that regard they are better than most commercial options for breathability and wood health. Expect 10–15+ years of service with occasional maintenance re-coats (no scraping needed, just clean and repaint).

Pigment blend is excellent for exterior durability and colour. The total pigment load (~2.56 kg) gives good hiding power. Green iron oxide + whites should hold colour well outdoors.

Iron oxide green provides stable, light-fast colour with good UV resistance. Iron oxide pigments (including green variants or blends) are standard in commercial linseed paints for outdoor wood/metal and hold up well to weather.

Titanium dioxide is added for excellent opacity, UV protection, and weather resistance.

Zinc oxide is traditional in exterior linseed paints for added hardness, gloss retention, and mild mildew/algae resistance. This mix is close to commercial ratios that pair TiO2 (for coverage) with zinc (for toughness).

Linseed oil is the sole binder and penetrates bare wood deeply and keys mechanically into abraded surfaces. The ~0.88:1 pigment-to-oil ratio by weight is on the higher side (many traditional recipes are closer to 0.5:1), but it should produce an opaque, protective film. The refined recipe is a version with a lower pigment load.

Drier is roughly in the safe 0.1–0.5% metallic drier range. It speeds up oxidation/drying without risking wrinkling or brittleness. Linseed paints dry slowly anyway, often over days to weeks per coat outdoors.

Bentonite clay at ~0.4% of total batch is used as a thixotropic suspending agent. It prevents heavy pigments from settling during storage/application, which is a common issue in oil paints.

Mixing & Preparation

Disperse the dry pigments thoroughly into the oil first (use a muller, high-shear mixer, or paint mill if possible) before adding drier and bentonite. Poor dispersion leads to streaky or weak film.

Add bentonite gradually while stirring for full effect.

Application Tips

Apply very thin coats (2–3 total) in mild weather with good airflow/UV (drying improves with light but avoid direct hot sun).

On bare spots: Let oil penetrate; wipe excess if needed.

Full dry time: 48+ hours per coat (longer in cool/humid conditions); wait fully before re-coating.

Coverage: This ~5.5 kg batch should cover roughly 20–40 m² depending on surface/coat thickness.

Refined version

Quantity	Ingredient
1.0 – 1.2 kg	Iron oxide green pigment
0.8 – 1.0 kg	Titanium dioxide
360 – 400 g	Zinc oxide
2.9 – 3.1 kg	Raw or boiled linseed oil
4–6 ml	Drier
20–25 g	Bentonite clay

Original

Quantity	Ingredient
1.1 kg	Iron oxide green pigment
1.1 kg	Titanium dioxide
360 g	Zinc oxide
2.9 kg	Raw or boiled linseed oil
4 ml	Drier
20–25 g	Bentonite clay

Primer (1 litre batch)

This primer recipe is a classic, highly suitable penetrating sealer/primer for a linseed oil paint system on external wood. It aligns well with traditional practices for bare wood and mechanically keyed (sanded/abraded) existing finishes. It will soak deeply into the porous bare spots, seal the wood, improve adhesion for the topcoats, and provide a uniform base without creating a heavy film that could trap moisture.

There are two variants. The first is a penetrating primer that contains a higher solvent load to get properly into bare wood, particularly older drier wood. The second variant has a higher linseed oil load and is more suitable for a second coat over bare wood and as a surface primer/undercoat on mechanically abraded existing finishes.

Raw linseed oil is excellent for penetration into bare wood. Raw linseed oil wets and bonds deeply, nourishing the wood and creating a flexible, breathable foundation that matches the topcoat chemistry perfectly.

Solvent thins the mix for better absorption and flow. 20–30% is a good range with enough to reduce viscosity without making it too weak or overly slow-drying.

Titanium dioxide gives a slight opaque "wash" effect, helps with UV blocking even in the primer, and provides a better visual base for the topcoat by improving hiding. Many traditional recipes add a small amount of pigment to primers for this reason. The lower ratio enables maximum penetration.

Drier is added in a low dose to speed up drying safely without causing wrinkling or brittleness.

Mixing Instructions

Disperse the dry pigments (TiO₂ + ZnO) thoroughly into a small portion of the raw linseed oil first. Use a high-shear mixer, paint stirrer, or muller to avoid lumps/clumps.

Add the rest of the oil, then the solvent gradually while stirring.

Add drier last.

Stir or shake well before each use; pigments may settle slightly over time (bentonite could be added at ~0.2–0.4% if needed for suspension.

Application Tips

Apply very thinly (flood on, then wipe excess after 10–30 min) on clean, dry wood.

1 coat of penetrating primer on bare areas; 1 coat of surface primer on well-keyed existing finish and after the penetrating coat on bare areas.

Allow full drying: 3–7+ days per coat (longer in cool/humid conditions) before topcoats.

Test on a small section first.

Surface Primer Recipe

Surface primer

Quantity	Ingredient
750 ml	raw linseed oil
200 ml	solvent white spirit
60 g	titanium dioxide
40 g	zinc oxide
1.5 ml	driers
~0.2–0.4%	bentonite clay (optional)

Penetrating Primer Recipe

Penetrating primer

Quantity	Ingredient
680 ml	raw linseed oil
270 ml	solvent white spirit
60 g	titanium dioxide
40 g	zinc oxide
1.5 ml	driers
~0.2–0.4%	bentonite clay (optional)