Effect of weather on deposition efficiency

[Max K]

Hello everybody,

How weather effects deposition efficiency? Number of passes increase during rainy days. Happens when I spray top coat of TBC with SG2086 gun.

Thank you.

[Gordon]

Hi skimen777

Interesting observation.

Is it actually deposit efficiency that is effected or the application rate? i.e. changes in powder feed characteristics or speeds and feeds of gun/part.

[Max K]

I think it is actually application rate. My number of passes increases to get to the required thickness.

[GMA thermal spray systems]

Pressure in bottle drops due to temp going down. apply Bernouilly factor correction. Powder get moisture also. Preheat them.
Moisture of the air cool the flame and reduce efficency.
For some critical operations, sometimes a 1 % parameter variation can affect 30% of the coating. This is the reason some users have several rooms heated. this effect is known 40 years ago by previous thermal spray users. You must compensate the energy drop at the gun but also in the environnement (spray room temperature, preheating the substrate)