Burgundy Mist Nitro - where???

[Marcel]

Thanks Simon ... very helpful...

[Simon Barden]

With any spray paint, you get a two stage cooling effect. One as the propellant gas expands as it leaves the can, the other as the solvent evaporates (latent heat of evaporation). So if it's already on the cool side before you star spraying, then the paint will cool down a lot more as you spray. Get it cool enough to saturate the air and you'll get moisture droplets forming on the drops of paint, and trapped under paint arriving on top of it, which is why you can get the misty effect. The solvent in nitro is pretty volatile, so it evaporates quickly and cools down a lot more than many other paints, making it more susceptible to low temperatures.

The more humid the air, the less it needs to cool down before it reaches saturation and form those small droplets.

[Marcel]

I'm guessing that investing in one of those little weather stations that tell temp and RH might be a good idea if coating in nitro is a definite. And the pick warm and dry as the ideal time to spray... 25C @30%RH probably being close to ideal

[Simon Barden]

50%RH is fine. It's when its 80% plus that it becomes an issue when warm, maybe 70% when it's cooler.

Be wary of the %RH values from the low cost weather stations as they are normally quite inaccurate on the %RH side, maybe ±10% at best. Use it as an indicator, rather than as an absolute guide. Also, it needs to be in the place you're working rather than outside. And remember that it needs to be kept out of direct sunlight or you'll get higher temperature and lower %RH readings.