Sand scratches and feathering.
If you've read any of my other posts, then you know I'm as rookie as they come.
This is a great website, and guys who contribute answers and advice to the forum and greatly appreciated.
Here is my question/problem:
I'm repairing a wheel on my car. Painted alloy. No problems with the color match or spraying. My problem is that after I've laid down my basecoats, and I get down really close to inspect it (because paint seems to magnify any imperfections) I keep finding sand scratches under the paint. In the end, I've just decided to clear over them and call it good. After all.. it's on a wheel and once you step back 18" you don't really see it anyway. But I want to get them right.
This is has been my process: I'm filling with Icing, Sanding down with 240 until it's "close" then wet sanding with 500,800,and/or 1000 depending on how they look.
I then prime, and look for uniform surfaces. Which.. I always find one or two. I refill those and repeat my sand process. Then prime again, and wet sand with 1000 til it feel smooth by my finger.
The problem I run into is that when I look at my final product (Ready to paint) I can see all sorts of surface scratches in it. But it feels silky smooth, and I figure it's just the dullened effect of the 1000. Then I clean, tack and lay down my paint and they stand out like a neon light.
The first time I did this I figured, "eh.. first time mistake. I'll get it right on the next one." But the next one has them too. Not as bad, but they are there.
Am I just not wet sanding long enough? Wrong grit? I don't it.
What grit is used when first taking down your filler? Do I take it all the way down to where it is only showing in my low spots, or should I leave it covering a large area? And what should be the last grit to touch your surface before you paint?
Any help would be greatly appreciated.
When we are working a filler material we usually level it with 36, 80 then 180. After the filler is level we prime then apply a filler primer and guide coat and wet sand with 400 if it's a solid color or 600 if it's going to be a metallic. We rarely sand with anything finer than 600. When you're working with much finer grits you may not be sanding to the bottom of the valleys created by more coarse grits, use a guide coat to better see the surface while you sand. A dry powder-type of guide coat is best for dry sanding and an aerosol guide coat is best for wet sanding.