Was doing quite a bit of spray priming the last few days and wanted to share some observations on what I experienced.
I use black primer for almost everything that I model, terrain and miniatures. The two primary brands that I use are Armory Black and GW's Chaos Black.
I live in CT where it's a typically warm August with a fair amount of humidity. I have a basement where I can spray prime and open the cellar doors for ventilation. But the odor of the stuff still creeps up into the house. Our garage is the better choice where the vapors can fully dissipate outdoors. A little later in the early fall I can go back to priming outdoors when the humidity goes away.
But I wanted to get some miniatures done now and decided to try some experiments with both brands.
It was about 83 degrees here yesterday afternoon with pretty decent humidity in the 60s% range.
I first used the Games Workshop Chaos Black on a few dwarf plastic miniatures. The GW spray was flawless and totally unaffected by the humidity, the miniatures had a crisp, clean finish with perfect detail. I went ahead and primed pretty much the rest of the dwarf army with the GW stuff.
Then I experimented with the Armory Black. The Armory primer appeared to spray and adhere normally. However upon closer inspection I saw that the Armory spray was kind of like "chalking up" on the miniatures a bit, it was landing on the miniatures and leaving this fine grit texture. In other words, it wasn't adhering properly to the miniatures. I concluded this was due to the humidity.
To prove this, I took the rest of my plastic minis. inside into the basement where we have climate control as well as a de-humidifier.
Sure enough, when I used the Armory spray in dryer, cooler air, it suddenly worked fine and the finish on the minis. was clean and flat with no grit or "chalkiness".
So for me anyway, in this instance at least, the GW spray primer appears to be the superior product. And not just because of the humidity either. The GW spray generally leaves a smoother, cleaner-looking primer finish whereas the Amory covers fine but the finish always feels and looks slightly rough and "dusty" is the best way I can describe it.
Have I discovered something here? I don't know – maybe, lol. For those of us to love to hate GW, I have to admit that in this case it appears that GW's spray is pretty darn good and can be used even in high heat and humidity.
Who knows if this is truly due to GW actually using a higher quality formula or just pure chance. I doubt GW manufactures its own spray paints, they're probably from a central source/supplier that makes paints and primers for general use.
BUT – there IS a definite difference in the formulas between GW and Armory, and from what I experienced, the GW primer is the better product.