Ye Olde Rocket Forum - View Single Post - New Krylon Cover Master Paint

Quote:

Originally Posted by frognbuff

I think Krylon changed formulas again. I pretty much stopped using Krylon after the last formula change, but I still use Krylon Primer (gray or rust). It's cheap, covers well, dries fast, and sands easily. Bought a new can this week and everything is different - the can, the spray nozzle (big one like on Rustoleum cans). It sprays different and smells completely different. Any Krylon users out there seeing other differences?

Wouldn't surprise me....

I gave up on Krylon when they went to those terrible stinking "rotatable flat fan" pattern nozzles.... it just hosed paint onto the rocket and gave TERRIBLE atomization...

I'm a farmers-- I spray for a living... the round solid cone or hollow cone pattern provides THE best atomization of any pattern, bar none, which is THE most important factor for painting small stuff and with inexperienced painters... Now, it's TRUE that even flat fan patterns provide more CONSISTENT atomization in terms of droplet size distribution, but the droplets are MUCH LARGER and the spread of the pattern and direction, speed, and distance as well as angle between the spray nozzle and the target become MUCH more important to achieving good results than with the cone type patterns... IOW, they screwed up-- they figured by copying "auto spray guns" with their cheapy nozzles on the rattle cans that they were doing something smart... JUST THE OPPOSITE-- the cheap "cone type pattern" spray nozzles provide a MUCH better covering pattern with a denser cloud of smaller droplets, and due to the inherent angle of the conical pattern, the coverage is much more consistent regardless of the can angle... As the nozzle passes any given point on the surface being painted, the first droplets arrive at an "forward swept" angle, then "straight down" or perpendicular to the surface, then the last droplets to arrive come in at a "swept angle" or rearward angle as the nozzle sweeps away from the area being painted... the density of the pattern and amount of paint deposited on a given area is primarily a function of 1) speed of the spray pass and 2) distance of the nozzle from the surface (wider vs. narrower pattern).

The flat fan nozzles, in addition to suffering more pressure drop because basically the paint is flowing through TWO orifices (the nozzle body itself and the flat fan producing orifice, which is a trick used in ag spray nozzles to create larger droplets less prone to pesticide drift, but which give TERRIBLE coverage and are only useful for CERTAIN APPLICATIONS AND PRODUCTS... IOW, mismatching the nozzle and job/product is likely to cause an expensive failure!) The coarser droplets arrive mostly "straight down" onto the target, in a "sheet" as the nozzle passes over a given point on the surface being painted... This pattern is ESPECIALLY difficult to get good coverage when you're painting complex shapes like cylindrical rockets with fins and other protuberances... Flat fans are FINE for spraying acres of cropland, or large flat expanses of fenders, hoods, roofs, and trunks of cars, maybe even lawn furniture and crap the average homeowner is shooting with rattle cans... but for complex smaller shapes like rockets they're a TOTAL PITA...

Later! OL J R