Painting a Gas Tank — Which Paint Lasts?
Painting a gas tank (propane, LPG or an outdoor heating oil tank) looks trivial, but it comes with special demands: strong UV exposure all day, thermal movement from changing fill levels and sunshine, and the need to limit heat build-up in summer. Conventional paints typically fail after 3–5 years — cracks at the welds, flaking on the sunny side.
A liquid rubber coating (also called rubber paint or flexible coating) solves these problems — it stretches with the tank, reflects more sunlight in a light colour and stays intact for 10+ years.
Why conventional paints fail on gas tanks
- The sunny side of the tank heats up to 60–70 °C — the steel shell expands and rigid paint cracks
- Beads and welds are weak points — thermal stress builds up there and conventional paints flake off
- UV radiation for 8+ hours a day — acrylic and alkyd paints chalk and turn grey
- The fill level changes — the temperature of the metal changes with it, and the outer wall moves slightly
Which paint for the outside of a gas tank?
For the outside we recommend liquid rubber / rubber paint for the following reasons:
1. Highly elastic — follows thermal movement
Elongation > 300 % to DIN ISO 527. Even with a 40 °C temperature difference between the shaded and the sunny side, there is no stress cracking.
2. UV-stable class A0
The highest UV resistance class to EN 1062-7 — the colour stays stable for 10+ years.
3. A light colour reduces heat build-up
In white (RAL 9003) the material reflects over 90 % of incoming sunlight (SRI ~95). That lowers the tank's surface temperature in summer by 15–25 °C — important for pressure behaviour and safety with LPG.
4. Straight onto old paint or lightly rusted steel
No complete rust removal needed. Scrape off loose rust layers; any remaining surface rust can stay — rubber paint bonds directly to it.
Application: painting a gas tank in 4 steps
- Clean. Pressure washer (max. 120 bar) — remove cobwebs, dust and algae. For grease: methylated spirit or acetone.
- Prepare. Remove loose paint and flaking rust with a wire brush. If needed, briefly key the welds with 80-grit abrasive paper.
- First coat. Thinned with 5–10 % water so it works well into welds and beads. Consumption approx. 150 g/m².
- Second coat. Undiluted, after at least 4 hours of drying, for the full film thickness. Consumption again approx. 150 g/m².
Recommended colours for gas tanks
- White RAL 9003 — the standard for heating oil and propane tanks, best UV reflection, optimal for safety
- Grey RAL 7046 — a discreet, well-covering grey for tanks that are on view
- Green RAL 6005 — blends naturally into gardens
- Graphite RAL 7024 — a modern look, but it heats up more in summer
Safety notes
- Make sure no gas is escaping while you paint — have the tank checked beforehand
- Don't work near open flames or flying sparks
- On LPG tanks: don't work directly on the valve
- For heating oil tanks indoors (e.g. a boiler room): use only solvent-free, water-based coatings such as our rubber paint
Consumption and cost
A typical 1,000-litre outdoor heating oil tank has a surface area of approx. 5.5–6 m². At 0.3 kg/m² (two coats) that is approx. 1.8 kg of rubber paint — a 3.5 kg tub covers one tank with some to spare, and a 6 kg tub covers two tanks or one large 5,000-litre tank.
Conclusion
For gas tanks, liquid rubber / rubber paint is clearly a better choice than conventional paints thanks to its elasticity, UV stability and heat protection. In white it also noticeably lowers the tank's surface temperature — important for safety and vapour pressure with LPG.
Product: Liquid rubber paint White RAL 9003 →
Related terms: Our product is sold in DIY stores and the trade under several names — liquid rubber, liquid rubber paint, liquid membrane, rubber paint, rubberised paint, flexible coating, elastic exterior paint or polymer coating. They all mean the same product: a waterproof, highly elastic coating based on acrylic latex.
RubberPaint Team
Technical editorial · RubberPaint
