[jdss]

I've got the whole car primed with SPI 2k and block sanded with 320 grit.I'm going to spray Chromabase base coat( 65 chevy mist blue).I was told to sand to aleast 500 grit.I'll have to wet sand because the 500 will clog up right?When sanding with 500 do I still need to use the longest blocks I can to keep it flat or at that grit am I not really changing the straightness to much.I've read that some guys sand that fine with a DA.How could you keep it flat and straight with a DA?

[milo]

K, I'll bite ... curiuos where you were told to sand with that fine of grit..

http://www.a2zautoforums.com/showpos...9&postcount=30

Use a block if you want it straight , don't change sand stroke direction in the same place twice ..that simple...

[kenseth17]

Being the 320 was used by hand, I would say you are still too course, specially to just shoot base without sealing first. 320 if was by machine would be equivalent to about 400 wet, may be able to get away with some solids, or if shooting a sealer first.

To be safe, I would maybe guide coat and go over it one more time with about 600 wet using a block or at the very least a sanding sponge for back up for the areas you can get that way, and only sand by hand where needed. After I've blocked everything straight and reprimed, I do my final sanding with a small block or sanding sponge. When you get down that fine, it won't affect as much, but still could make something straight wavy if not carefull. Depends on how anal you are on this, the best would be to still use a hard block where you can with a longer block to be the safest with the least chance of creating waves. I would not sand with a da unless you are very good with it, leave the sanding primer with a da to the used car lots.

[jdss]

Thanks for the replys.

Milo,The chromabase tech sheet says 400 or finer.So far I have stripped the car then epoxyed over bare metal then filled the dings and blocked the filler with 80 then blocked to 180.I then sprayed 2 coats of 2k primer and blocked with 180.Next I sprayed 2 more coats of primer and blocked with 180and then with 320.Thats were I at now and to tell the truth I'm really tired of block sanding.

I guess I could spray a thined coat of epoxy on for a sealer.will that cover 320 scratches?With my skill level I'm sure the seal coat will need some spot sanding before base,so what would I be gaining?

[jcclark]

320 is to coarse to base over, especially "P" series paper.
Even 400 is risky, especially for silver colors.
Wet sand it all with 600 and you'll be good to go.
600 is to fine to affect straightness, 600 is for smoothness.
You can get by with a little coarser grit if you cover with a sealer first.
Or even a coat of intercoat clear before base will hide the scratches.
But the safest, is wet sand it all with 600.

[baddbob]

Originally Posted by jdss

Thanks for the replys.

Milo,The chromabase tech sheet says 400 or finer.So far I have stripped the car then epoxyed over bare metal then filled the dings and blocked the filler with 80 then blocked to 180.I then sprayed 2 coats of 2k primer and blocked with 180.Next I sprayed 2 more coats of primer and blocked with 180and then with 320.Thats were I at now and to tell the truth I'm really tired of block sanding.

I guess I could spray a thined coat of epoxy on for a sealer.will that cover 320 scratches?With my skill level I'm sure the seal coat will need some spot sanding before base,so what would I be gaining?

You could seal it and it would take care of the 320 grit scratches and be ready for paint but if this is a fine metalic you would get a much better job by sanding it with a finer grit. Fine metalics will highlight any scratch or surface imperfection like a mirror. Any texture in the sealer will show in a fine metalic color. Solid colors there's no worry.

No need to reprime at this stage, just apply more guidecoat-(this is a required step) and sand the whole car down with 600 till all the guidecoat is off. It really won't take you very long. The final step is to take two grey scotchbrite pads and stack them together for a good cushion and rub the whole car down making sure to get all surfaces including the edges. Then shoot your paint.

[outlaw17]

I always finish in 400 EXCEPT for colors that are silver based ,or heavy metallics , they seem to have a tendancy to show scratches a bit more , I finish with 600 for these colors.

[milo]

Originally Posted by jdss

Thanks for the replys.

I guess I could spray a thinned coat of epoxy on for a sealer.will that cover 320 scratches?With my skill level I'm sure the seal coat will need some spot sanding before base,so what would I be gaining?

The thing is down the road if you sand everything with 400 there will be better tooth (paint will stay) on the panel edges around door jambs ,gas doors,fender welts , key holes,hood springs,latches,where the mirrors go,around the antenna hole,under the hood.handles ect..

If you feel you want to sand with the "finer" 500 - 600 grit then just do the "show areas" out in the center of panels not where you know there will be rock hits and wear..

remember to post up some pics

[grouch]

Originally Posted by baddbob

The final step is to take two grey scotchbrite pads and stack them together for a good cushion and rub the whole car down making sure to get all surfaces including the edges. Then shoot your paint.

Photo.

Disclaimer: I'm a greenhorn newbie regarding paint and did almost everything wrong on the paint job in the photo. I liked the results of rubbing it down with those pads, though.