Some rust issues.

[Iron Ranger]

I got my ranger repainted 3 years ago and a trouble spot is the very lower rocker panel lip of the cab. Lots of salt, rocks and dirt managed to work themselves in between the metal and the original factory paint job which is now, I'm noticing, starting to make the paint chip off, exposing surface rusted sheet metal.

I have POR, but don't want to use it on exposed panels(UV rays mess with it over time), but when I sand the rust off, would self etching primer be best or could regular Krylon primer be used?

Also, I have the paint color for the paint job. Should I repaint and reclear the areas, or would an undercoating be better?

It's so low that no one will see it unless they get on their knees to look.

Any advice would be greatly appreciated!!! Thank You.

 

[IRKillroy]

the self-etching is good 'cause it'll kill any grease and grime so you won't need to use a prep spray or acetone (which ever you prefer) then you can sand it down and paint/clear it... that's probably best after you figure a way to prevent it from happening again...

good luck.

 

[Iron Ranger]

OK, um...... I worked along side the autobody expert when we were redoing the truck, and I can't seem to remember what sandpaper grit size to use on primer for best results on the color.

Could you give me a hint?

 

[IRKillroy]

depends on how bad the paint looks... if you need to take a lot off then you go with 1000 wet ... if it's pretty damn good then go 1500 wet until you are ready for your base coat... then you go back to 1000 wet and when you get to your clear start over but with that you finish it off with 2000 wet and then ... it's ok to get your old clear with the 2000, you will buff it all out into super shinyness...

just do enough coats for it to be a solid color without bumps or imperfections then move on to the next... so primer till it's smooth, then base color till it's solid and smooth then clear until it's solid and smooth then on the last coat you do 2000 wet sanding.

I'm being repetitive....

 

[magnum1]

If you sand the area with rust down & you see black where the rust was instead of shiny bare metal,then chances are the rust will return one day.(could be years away)
This usually will not sand out & it would require using a grinder.
You would then use a sander to smooth out the grinded area (80,then 180-220,400 grit to smooth back out)
Ething primer is for adhesion,not really rust prevention.
(take a thin bare metal panel,paint 1/3 with ething primer,1/3 regular primer & 1/3 with paint-let dry & then bend it several times-the ething primer section should be the only section that doesn't flake)
I would use the ething primer on the bare metal area,followed by a regular primer,sealer,then paint.
Areas that will receive paint,but no heavy sanding just need to be lightly sanded.
A scotch brite pad is close to 400 grit sand paper & can be done by hand wet or dry.
*paint sticks to lightly sanded paint better than anything
Good luck

 

[RangerFabWorks]

depends on how bad the paint looks... if you need to take a lot off then you go with 1000 wet ... if it's pretty damn good then go 1500 wet until you are ready for your base coat... then you go back to 1000 wet and when you get to your clear start over but with that you finish it off with 2000 wet and then ... it's ok to get your old clear with the 2000, you will buff it all out into super shinyness...

just do enough coats for it to be a solid color without bumps or imperfections then move on to the next... so primer till it's smooth, then base color till it's solid and smooth then clear until it's solid and smooth then on the last coat you do 2000 wet sanding.

I'm being repetitive....

when doing the final blocking of the primer for paint, you would use 400 grit. you dont wanna go to fine like 1500 ect because the paint does need a little roughing up to stick. if you take 1500 to primer, you can make it shine by just rubbing it with your fingers. in my experiance in the auto body, your paint doesnt stick to really smooth primer. it needs to be a little rough. but to get the rust out, start with 80, go 120, then prime with a good primer, outta a can id use duplicolor. but if you could order it, www.eastwoodco.com has a self-etch primer that works really well, then block 220, 320, 400, then your ready for paint. just make sure you wipe down the area with a good prep-all type cleaner. if you have a paint shop near you, do your self a favor, get this product called u-pol. its about 25.00 a gallon, but does a fantastic job cleaning, and dries extremely quick. my $0.02

 

[IRKillroy]

what black widow said.....


@ magnum.... the etching is to eliminate oils and other contamination that would otherwise screw with your bonding to the surface... that's why you use flux when you solder stuff... it's etch...

it's as you said an adhesion promoter but it does have it's limited capabilities to eliminate rust as you described being little black pits... that isn't rust, that is crap in the steel and usually water or moisture of SOME sort gets in there and causes oxidation to start back up... self etching primer practically eliminates that as a possibility... but if you had lots of it, then using acetone would be a more economical approach.