ok guys how do i start this big job? what grade sandpaper do i use for each stage? thanks guys!
sanding back a car
Started by
_lexa_
, May 02 2006 05:22 PM
8 replies to this topic
#2
_jabba_
_jabba_
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Posted 02 May 2006 - 10:30 PM
Depends what your trying to achieve, if your going back to bare metal id recomend somthing like 80grit then 180 to prep the metal before you spray primer.
<edit> spelling
<edit> spelling
Edited by jabba, 02 May 2006 - 10:30 PM.
#3
smeer
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Posted 02 May 2006 - 10:37 PM
I'm also interested in this.
Should we sand down finer and finer till its smooth? Or do you need some roughness for the primer to grip.
I'm going to have my steel dash bits sprayed in a booth professionally, but I want to sand and prepare it all for him.
Should we sand down finer and finer till its smooth? Or do you need some roughness for the primer to grip.
I'm going to have my steel dash bits sprayed in a booth professionally, but I want to sand and prepare it all for him.
Edited by smeer, 02 May 2006 - 10:38 PM.
#4
_lexa_
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Posted 02 May 2006 - 11:12 PM
sorry i should've mentioned. the paintjob on my car is actually very good in its current state. its a tribute to the factory 34 years ago, however its gold and i want red 
so all i'm looking at doing it going back far enough to respray. so it wont be a bare metal job.
so all i'm looking at doing it going back far enough to respray. so it wont be a bare metal job.
#5
_Eddie_
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Posted 03 May 2006 - 11:02 AM
If you're respraying in acrylic and the original paint is in good condition I'd use 120 to start with. There are 3 main type of sanding utensils, 1 is small cork block which is used for curved areas like over the wheel arcs, 2 is the bigger plastic/foam block, 3 is the line sander which are thin and over a foot long. For areas with high levels of rust, wire brush or angle grinder with wire brush come in handy.
If you want it real straight go around the first with the plastic/foam block on the curved panels and the line sander on the flat panels. Go to an auto paint shop for these products, avoid supercheap they sell crap. Corners/lips should be avoided with the line sander. For the areas where the line sander can't reach or the surface is too curved use the smaller blocks. If you sand back enough to see primer, stop immediately and go on else where. You should to spend equal time distributing sanding efforts around the car. I'd sand as much of your old top coat as I could with out going back to metal.
After you have removed all shitty paint, gloss on the paint, rust and any other imperfections, go around with a mist guide coat on the panels you want to get dead straight. Sand this back with line sander and you will see all the highs and lows on your surface. This is where the bogging/dent bashing comes in. This is also where a lot of pain and hatred comes in... not to mention the chemical effects of breathing bog in all day.
You can use these as general grit guides: 80-120 for bog and straightening, 120-180 for flatting out primer builder, 600 wet and dry before top coats.
If you want it real straight go around the first with the plastic/foam block on the curved panels and the line sander on the flat panels. Go to an auto paint shop for these products, avoid supercheap they sell crap. Corners/lips should be avoided with the line sander. For the areas where the line sander can't reach or the surface is too curved use the smaller blocks. If you sand back enough to see primer, stop immediately and go on else where. You should to spend equal time distributing sanding efforts around the car. I'd sand as much of your old top coat as I could with out going back to metal.
After you have removed all shitty paint, gloss on the paint, rust and any other imperfections, go around with a mist guide coat on the panels you want to get dead straight. Sand this back with line sander and you will see all the highs and lows on your surface. This is where the bogging/dent bashing comes in. This is also where a lot of pain and hatred comes in... not to mention the chemical effects of breathing bog in all day.
You can use these as general grit guides: 80-120 for bog and straightening, 120-180 for flatting out primer builder, 600 wet and dry before top coats.
#6
_Yella SLuR_
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Posted 03 May 2006 - 12:22 PM
You guys have it covered.
Only thing to add, don't sand in one spot for too long, you'll buckle panels. Again, control the heat. If using a sanding disk, work in one direction only in long strokes down the panel. Panel should be cool to touch at any stage of the process.
Only thing to add, don't sand in one spot for too long, you'll buckle panels. Again, control the heat. If using a sanding disk, work in one direction only in long strokes down the panel. Panel should be cool to touch at any stage of the process.
Edited by Yella SLuR, 03 May 2006 - 12:32 PM.
#7
_Aidan_
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Posted 03 May 2006 - 10:32 PM
That sounds beaut eddie but what if you want to use an electric sander to save your arms and time a bit? What one should you use, and would you do your method if you want to take it back to metal or would paint stripper be better suited?
#8
_jabba_
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Posted 03 May 2006 - 11:34 PM
Well i use a DA air sander for sanding back paint and wirebrush on a 4" grinder to cleanup any rust when going back to bare metal if that helps 
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#9
_Eddie_
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Posted 04 May 2006 - 10:18 AM
Paint stripping is messy shit, it gets everywhere and you still gotta neutralise all the chemicals even once you've gone back to metal. Sanders and grinders are good for removing paint. If you're not taking back to metal then just hand sanding is ok if the paint is in good condition. Personally if I ever paint my car again I'm just gonna get it sand blasted.
The advantage of respraying a car versus bare metal strip is you've already got a few mm of build to work with. The old paint acts as a builder you can level. If you hit it with a line sander straight away, you're straightening the car from word go. Just make sure get rid of all the top scum on the paint. The downside of this versus bare metal is you're completely at the helm of old paint been lying there for 30 years or so. There could be rust under the paint bubbling you can't see yet, or the paint may react badly with it.
The advantage of respraying a car versus bare metal strip is you've already got a few mm of build to work with. The old paint acts as a builder you can level. If you hit it with a line sander straight away, you're straightening the car from word go. Just make sure get rid of all the top scum on the paint. The downside of this versus bare metal is you're completely at the helm of old paint been lying there for 30 years or so. There could be rust under the paint bubbling you can't see yet, or the paint may react badly with it.
Edited by Eddie, 04 May 2006 - 10:21 AM.
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