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I've welded all the bad spots. I'm covering the welds with glass-bondo and starting to sand. I plan to paint over the original paint because it seems like tough stuff. Do I need primer over the old paint? I need someone to tell me what grit sandpaper to use. I'm "roughing" it now with 150 grit sandpaper. What's best for final sanding--200 grit, 300 grit, etc? What grit between coats of paint?

TIA,

kevin

Kevin,
depends on what type of paint your going to use. Base coat/clear coat? Single stage?
With base/clear i wouldn't use anything less than 600 grit wet/dry paper.
With single stage you can get away with 320 DA paper.
I would highly suggest at least putting a couple of coat of a good primer with a hardner to help lock down the old paint.
Any more questions just let me know!
Good luck!

As a rule.. you want to

1-repair any metal/paint issues..
2-clean the car
3-scratch the entire car with sand paper (depends on the product of which grit)
4-clean the car
5-inspect all details
6-prime (which exact depnends on the paint system)
7-then start your new color process.

Any missed steps will cause a failure.

I'm using Napa High Build Primer, found on the shelf next to the paint I'm using also. I'll double check before painting anything but I believe it said use 250 grit paper to scuff the old paint and then spray primer. Then use 600 grit wet/dry to smooth the primer before painting.

kevin

Sitting next to the paint may be misleading ---- it has to be the exact part number specified in the manufacturer's (not Napa) white paper. If I remember correctly Sherwin Williams makes Napa Paints.

Some of your sand paper sounds agressive and may cause finish scratches.

Do you have any books? Nomrally they'll speicify exact types of sand paper etc.

dont forget to get a good silicon grease remover and use fresh rag or i use the blue towels folded over. wipe on n use another to wipe off before you paint. alot of people miss this step n wonder later why t hey get fish eyes n etc