How to control roughness of coatings

[Zhangqiuping]

Hi,friends!
I want to control roughness of coatings when I spray it!
Can I achieve the target? What parameters I should pay attention to?

Thank you!

[Stuart Milton]

Which process are you spraying with (flame, arc, plasma, HVOF or other).

What materials?

Are you looking to make a coating more rough or smoother?

Do you have any roughness figures in mind?

Maybe an explanation of the potential application may help.

Sorry for so many questions but it will help all respondents to give you the most suitable reply.

[Gordon]

Hi Zhangqiuping

to the Surface Engineering Forum.

As Stuart says we need a bit more information so we can answer without writing a whole book on the subject.

[Zhangqiuping]

Thank you for your advices!
I spray with air compressor and spray gun!
I wish I can control roughness of coatings during the process I operate with hand!
The material is composed of fluorocarbon varnish and pigment!
I spray coating on aluminium in order to study the connection between the roughness and the optical performance!

[Gordon]

Hi Zhangqiuping

I think we wrongly assumed this was a thermal spray question

Not really my area of expertise, but I think the following factors will be important:

* composition and nature of your spray material
* viscosity
* air pressure/flow rate
* nozzle design
* Spray/stand off distance
* substrate/coating temperature
* substrate roughness
* post spraying baking/curing

[Zhangqiuping]

Thanks!
I will try it according to your suggestion!