Sanding side panels and fender

Could someone give me a general description on how to sand side panels and fender in preparation for painting ?

I would start with an 80 or 120 grit pad on my random orbital sander. Only use this until you cut through the clearcoat. Also, DO NOT get near any corners or edges with a power sander. It will wipe out a corner on a plastic part before you know it.

Now once the clear coat is cut through, then switch to hand sanding starting with 120 until you start cutting through the primer and seeing the black plastic underneath. One you start seeing plastic it's time to switch to finer grits and be careful that you don't alter the basic shape of the part. With that said, the final grit that you use to sand with should be determined by the recommendation on the data sheet of the primer you will be using. If you are repainting with any modern basecoat/clearcoat system, the data sheets will give specific instructions about the surface prep prior to painting.

I will say that I used PPG products when painting my bike and I love their high build primer. It covers a multitude of sins and it block sands so easily. Getting the prep and primer coats flat is the key to a good looking paint job.

Wash front and back with soap and water to get heavy dirt and grease off. Wash with wax & grease remover to get squeaky clean. If they haven't been repainted just scuff them up and feather out nicks and scratches.

Alright guys that gives me a guideline to start with. There's so much crapped up paint on this bike that the paint is full of cracks. I'll be a couple mins sanding this stuff down.

So should I take my time and sand all the way to the black plastic since the paint is in such horrible condition ?

If there are multiple layers of paint and the paint is cracked and or peeling it isn't a good base coat in my opinion. I would sand it all off if it were me.

I won't put words in Paintworks mouth, but I think his advice applies if your existing paint were in decent shape. Sounds like you may be a little worse off based on your second post.

That's my $.02. Take it for what it's worth. I'm not a professional painter.

Haven't had occasion to try it yet, but I hear an overnight soak in brake fluid will save one a lot of sanding time. I can tell you CHANGE YOUR WET-SANDING WATER OFTEN!! I got a piece of 600 grit in my 2000 wet/dry paper from contaminated water and really zonked my Metallic Silver basecoat. Back to sanding... (Now where IS that DOT 3...)?