I want to powder coat my mirror arms. Must they be taken down to bare metal for the powder to adhere or can I simply sand the existing paint to powder coat? Secondly, do you need to put a primer coat on before powered coating?

 

Powder coating as an electrostatic process. You need bare metal for the powder to stick. No primer is needed. After the powder is applied, it's baked on.

 

Most powder coating companies will strip the item first anyway, as part of their process. At least that's how it works this side of the pond.

 

They need to be bare metal. No primer.

Powder Coating 101

 

While maybe not entirely relevant to mirror arms if they have not been lubercated, a tidbit I have learned.
If the object has been subjected to oil or other contaminates over its life sandblasting may not get to all of the hidden areas where the oil/grease or stuff has traveled. Baking is a way this may be addressed cooking the contaminates before sandblasting and powder coating. I have had parts come back with flaws from contaminates.

 

Let the shop take care of the prep...my guy usually sandblasts everything before starting the coating process.

 

Yeah, they're real particular about it. Anything I did would be for not because my guy would just re do it and media blast it his way anyhow. I remember I took in an aluminum motorcycle frame and stopped to check on it. He took me over to see it after it was blasted. It looked so cool the texture of the aluminum. I felt like I needed to touch it. As my finger neared it to touch almost like in slow motion he let out a "Nooooooooooooo!!!!!!!". He said if I touch it he would have to completely clean it again. He's real particular. But said that the coating could lift in that spot just from a finger print when it goes in the oven.

 

I'm still learning, but I sand blast, hit it with brake fluid or acetone, tac-cloth it and then bake it. After all of that, I then coat it with powder.

 

Thanks guys. It was just for my stock mirror arms. The paint on them is pretty good now so I think I will just sand them and repaint.