What grit to use?

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PostPosted: Tue Dec 16, 2014 10:28 am
I'm doing one car, I'm a first timer. I have to take the car down to bare metal, some areas will need light filler work and it will be painted black.

So far I have 80 grit for a 6" DA, 80 grit for my blocks and 180 for my blocks.

To take it down to bare metal I might go buy some 40 grit for the DA.

What grits can you jump to from one to another? I don't want to buy every grit needed at once, I want to have the grits needed for taking the car to metal, then epoxy, filler work and high build blocking.

Any recommendations on what to buy at this time? I'm not worried about what's needed to buff and cut at this time, just want to have what's needed from metal to high build. Once I'm at the point of having to spray base I'll buy the appropriate grits at that point.

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PostPosted: Tue Dec 16, 2014 11:15 am
You can use 40 grit on your DA to strip paint but I recommend you go over everything with 80 grit on your DA before applying epoxy primer.
Apply your filler and block sand level with 80 grit. When happy with it skim coat with filler and block with 180 feathering into surrounding area before spraying 2k build primer.
1968 Coronet R/T


ACTS 16:31



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PostPosted: Tue Dec 16, 2014 11:37 am
'68 Coronet R/T wrote:You can use 40 grit on your DA to strip paint but I recommend you go over everything with 80 grit on your DA before applying epoxy primer.
Apply your filler and block sand level with 80 grit. When happy with it skim coat with filler and block with 180 feathering into surrounding area before spraying 2k build primer.


After I'm happy with the filler you want me to put a skim coat of filler over the filler, like glazing puddy, I figured I would feather in the filler either way, sorry I'm a noob lol. Do I need to do this if I plan to do a high build primer?

Also I was going to go with contour polyester from eastwood as a high build, I guess polyester doesn't shrink? Should I do this or go urithane?

Thx

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PostPosted: Tue Dec 16, 2014 3:48 pm
Most newbies don't spread the filler far enough past the dent they are filling.
The skim coat should extend well past your repair so there is no chance mapping. Its a very thin coat and will require very little block sanding with 180 to feather.
1968 Coronet R/T


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PostPosted: Sun Dec 28, 2014 3:39 am
Question about the first post...

What grade system is the above in reference too? I am going to assume all the gritt numbers were quoted in the "P" system.

http://www.thesandpaperman.com.au/abras ... chart.html

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PostPosted: Sun Dec 28, 2014 4:42 am
Nope. They are US grades. P400 is way too coarse for topcoating. If you're going to assume anything, then assume that the grades are in the US system. Even better, assume nothing and rely instead on the Tech Data Sheets for the products you're using. Much safer.
Chris

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PostPosted: Sun Dec 28, 2014 8:56 am
Sorry, I believe most if not all grit discussions here are using the P rating system. We've always advised that p400 is ok for under base, if a solid color. If shooting metallics then p600 is suitable. Generally, I always advise p600 since that eliminates the decision.



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PostPosted: Wed Jan 07, 2015 6:54 am
I sanded with 400 after clear once...Once! First car I did and I was working that job for a week..learned my lesson



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PostPosted: Fri Mar 13, 2015 12:30 am
Great site and info!

I just want to confirm a few things.

If respraying:
1. Sand down to old basecoat with 80
2. Use filler for any imperfections. (could use a guide coat and block with 80 to determine low spots?)
3. Block sand old base/filler with 180-220 using guide coat to assure panels are straight and feather filler as needed.
4. Spray high build primer, block sand with guide coat & 600. (using silver metallic)
5. Spray base, clear, buff, polish.

Whereas a full strip:
1. Strip to bare metal with 80.
2. Spray epoxy Primer to seal from rust.
3. Sand with 80/ guidecoat to show low spots.
4. Filler
and the rest of the steps the same.

Sorry I am completely new to this and just want to make sure I will get good results. The car has been painted about 7 years ago and it is holding up very well but the color needs to change.

Thanks for any help!



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PostPosted: Sat Mar 21, 2015 6:50 pm
'68 Coronet R/T wrote:You can use 40 grit on your DA to strip paint but I recommend you go over everything with 80 grit on your DA before applying epoxy primer.
Apply your filler and block sand level with 80 grit. When happy with it skim coat with filler and block with 180 feathering into surrounding area before spraying 2k build primer.


So I put my filler on bare metal before epoxy, how high of a grit do I have to sand to before I epoxy over it?


I most likely will do high build in the future but I need to epoxy everything still.
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