In Preparation for Ceramic Coating ?

[Churchy]

Just to show I have no idea about ceramic coating what-so-ever. I am going to ask the most basic questions and work my way down from there.

I may not know much, but I can lift heavy things .

I have just about finished fabricating the sidepipes and collectors and we are going to get them ceramic coated that dirty off white colour. The colour may not be to everyone's preference, but I'm using a chev engine, so I just have to keep being different.

So to the questions. How much prep work is required on the metal prior to dropping it off at the coaters. Seeing as we are not going shiny chrome or the like, do I need to polish the welds or the actual pipe itself, or does this type of finish "fill in" any smal imperfections. I have no issue doing it, but if it is not needed I won't do it. I intend to linsh the accesable welds back and have them smooth, and I have had the ones where I can't flap disk or linish, welded by somebody who actually has some skill.

Also how much material is laid down once coated ? If I was working with very fine tolerances and need to allow clearance for bolts holes or lining up of holes. How much should I allow ? As mentioned I have no idea about this. I do have a little experience with powder coating and know that you really do not need to allow for the deposited material (nothing a file won't fix anyway) when working with bolting things back together after coating.

Thanks