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What grit sand paper should i use?


77z280

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Ok so i'm new with the who;e bpdy work stage and was hopeing i could sand my vehicle and do alittle extra work to help save me some money. I'm not sure what sand paper i should use but does anyone have an idea on what grit i should use for old rusty parint? Also i'm using some rustoleaums rust reformer to hopefully slow down some of the rust in some spots and to hopefully save me the trouble of ersanding the interior in some spots but has anybody use rust reformer and spray on sound deader? I f so did you have any future problems with it and if so how did you fix it?

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800 grit is a bit too smooth.. Especially asking primer to stick to it.

 

The way I was taught to do any refinishing process is usually something around the following.

 

So you have a car you want to paint... It has some rusty spots.

 

1. Media blast all rust (sandblaster or something of the sorts) cheap harbor freight kits work fine.

 

once rust is taken car of and cleaned. You can always clean the rust the same way I describe below, but it is VERY difficult to not have it come back without blasting it.

 

 

 

2. Strip entire car of any paint (some people like using stripper, like previously mentioned, I prefer a soft and fine 6 inch wire wheel on my grinder.) Wear a mask. Protect your lungs. Goggles too.

 

once the car is stripped of paint

 

 

 

3. Fix any problem areas in the metal (body work stage, now you fix dents, remember: work the metal first, don't just add Bondo. Work the metal in the reverse of how the damage occurred. The rule "First in, last out" comes to mind)

So work your way from the least damaged areas to the deepest worst part of the damage. Don't start at the lowest point of the dent first and try to pound or push it out, that will most likely warp the steel, and add to your troubles.

 

once the dents are roughed out

 

 

 

4. Sand entire vehicle with the following progression:

 

 

40-60 Grit initially (for Bondo and first sanding stages body work areas, don't need to sand the whole car with this grit if it isn't damaged)

 

80-100 Grit (smoothing out your worked area, and taking care of any scratches left by paint removal) Don't skimp this step, anything you can feel with your fingernail will be a MOUNTAIN under paint. Take your time.

 

150-180 Grit (sand the rest of the car/area to be refinished (Make sure you are using "X" patterns while sanding, as you will continue this process until the end) if you don't know what that is let me know.

 

Primer does NOT like to stick to anything above this grit really (smoother than 180). The smoothing/straightening stage really happens next.

 

 

5. Now you PRIME the vehicle/area to be refinished: there are lots of different primers too. The process usually progresses something like this: Etch Primer (LIGHTLY over bare metal areas) --> Filler or High build primer --> Primer Surfacer --> Primer Sealer

 

Each of those stages is allowed to fully dry and is sanded (with the exception of the etch primer, spray your first coat of high build primer over this) with the same 180 grit, and eventually, when you are sanding the final layer of primer sealer, you move up to 220 dry (or 320 wet) I prefer wet, as it saves dust.

 

(Don't forget to continue using "X" pattern sanding techniques, and guide coat, which I can also explain if need be. Its basically just flat black spray paint that you lightly coat the areas to be sanded with; this allows a visual cue as to the straightness of a panel. PM me if you have questions)

 

So now your car is fully primed, and sanded with 220 dry (or 320 wet)

 

and hopefully its looking straight at this point.

 

6. Now you may begin to START thinking about paint.

 

 

Now this is a very generalized idea of how to refinish an area. There are most definitely fine details I left out, but for the sake of space I will answer them when/if they come up. Not everyone works the same way.

 

This is the way I was taught. I am a certified auto body technician.

 

If you have ANY questions, please feel free to contact me. I don't mind one bit helping people with paint/body work questions.

 

Best of luck!

Edited by OldAndyAndTheSea
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