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Wed Dec 16, 2009 10:30 pm

I just purchased paint and am almost ready to paint my buggy. The last coat of high build (poly-primer) that I used came out kinda textured (not that flat). I ma sanding with 220 till I get it nice and flat and then I plan on wet sanding with 400 prior to laying down the paint. My question is.... is the 400 grit a good grit to make sure that there are no sand-paper scratchmarks left by the 220 grit? I think that I am on the right path but after all the work I have put into the body, I wan to make sure so that this thing comes out as beautiful as possible. Thanks for the help, and here is the most recent pic just so you have a visual of what I am talking about.

Wed Dec 16, 2009 10:33 pm

If you are using a solid color it should be fine. If its metallic, you should use 600 wet. I personally would use 600 wet anyway :D

Wed Dec 16, 2009 10:38 pm

Yeah it is metallic. Good info. So 400 and then 600? Or just straight to 600 from 220?

Wed Dec 16, 2009 10:42 pm

I would do the 400 then to 600. But really either way. You may want to spray yourself a guide coat with black to be sure there are no scratches left before painting. Pretty hard to see em without

Thu Dec 17, 2009 6:19 am

scotch brite pad after all the sanding

Thu Dec 17, 2009 9:56 am

I know this is going to sound stupid but isn't scotch brite (grey) more abrasive than 600 grit sandpaper? Is that going to help smooth out any potential left over scratches?

Thu Dec 17, 2009 11:09 am

red ( fine) is about 500 and ultra fine ( gray ) is about 700

Thu Dec 17, 2009 3:28 pm

Red scotch brite rules! I like to scotchbrite right before I paint, that way I know there isnt any areas that got hard and there is just the right "tooth" for the new paint to stick to. Plus thats one more time to look things over to check for flaws.

sand
scotchbrite
blow it off
wax and grease remover
tack
paint

I also wear gloves from the time I bust out the scotchbrite til its painted, otherwise I touch everything.

Thu Dec 17, 2009 6:23 pm

So scotchbrite wet?

Thu Dec 17, 2009 7:13 pm

I use em dry, but they do sell a scuff paste that you can use to with a wet scotchbrite that is real nice too.

Thu Dec 31, 2009 9:53 am

Alright, I am second guessing my proposed plan of attack. Ihave yet to hit the buggy with 400 grit but looking at it in the light I see some pretty deep scratches (from the 220). I want to make this thing right so I am willing to put in the work. My question is, should I just put on another layer of primer and then hit it with 400, 600 wet and the grey scotchbrite pad? I just dont want any surprises in the paint. If so I only have the poly primer, so my follow up question would be could I just use the thinner top half of the primer (in other words dont mix it with the heavier filler material that sinks to the bottom)? Would it still cure correctly?

Thu Dec 31, 2009 10:19 am

don't mess with you mixs, you can put some more reducer than called for, but do so with care.
dry sand 400 w/paper the gp red pads, then gray,

Thu Dec 31, 2009 3:11 pm

spook wrote: red ( fine) is about 500 and ultra fine ( gray ) is about 700 red is general purpose..(320 to 400)

Thu Dec 31, 2009 3:15 pm

the reason we sand w/400 dry then scuff is to catch any remaining errors
moving to quick is a good way to screw up

Thu Dec 31, 2009 3:39 pm

streetbuggy8804 wrote: Alright, I am second guessing my proposed plan of attack. Ihave yet to hit the buggy with 400 grit but looking at it in the light I see some pretty deep scratches (from the 220). I want to make this thing right so I am willing to put in the work. My question is, should I just put on another layer of primer and then hit it with 400, 600 wet and the grey scotchbrite pad? I just dont want any surprises in the paint. If so I only have the poly primer, so my follow up question would be could I just use the thinner top half of the primer (in other words dont mix it with the heavier filler material that sinks to the bottom)? Would it still cure correctly?

If your not sure, spray it with a black dry mist (guide) coat. Spray paint will be fine. Then when you sand, if there is a scratch remaining, it will show up with the black still there. If it looks like its all gone, your good to go. If you see some scratches, you can either sand more, or spray more primer.
And as spook said, the more times you go over it the more likely you are to find things you may have missed. If you miss a flaw when sanding, you may catch it when scotch briting it, if you miss it there, you may catch it when you wipe it with wax and grease remover, if you miss it there, you may catch it when tacking it down.

And dont deviate from the manufacturers specs, they know what they are doing! A little extra time goes a long way in the end result. You will be happy you did. If it looks like it needs more primer (even if you have just spent hours sanding) then spray more primer, dont rush the process, it WILL make you pay!! You will kick your own ass every time you look at the car that you didnt spend the little extra time or money on to make it perfect.

Fri Jan 01, 2010 6:31 pm

just sprayed 3 coats of primer on my 58 three days ago then started to wet sand car .before starting to wet sand I used a guide coat from a spray can . everything looks great but a few ?? sanded thru to metal etching primer in a few spots and in others I must have missed with the epoxy and filler primer and sanded thru to metal . I know I have to reprimer but must i also first reprimer with metal etching primer ?? or will filler primer be ok ?? also where the guide coat is in spot weld holes will i have to remove ??