Help prepping chipped rocker panels for bed liner?

Hey guys, as the title would indicate, I'm getting ready to monstaline my rocker panels on my truck. The reason I'm doing it is because there are some HUGE paint chips and spots missing from the PO.. I'm assuming from driving on gravel..
Passenger's side (sorry for bad quality):

Driver's side:

As you can see there are some pretty rough spots in it that look to be all the way down to the primer.
Normally when you apply this bed liner to the rocker panels, you sand it down a little but not all the way down past the paint. So I'm wondering how I'm gonna do that with paint missing. I could, but I would still have the chips that are down to the primer and all the rest sanded correctly. Then I would be worried about it chipping again. I just want to know how to prep this surface for the bed liner. Is there anything I can do to even it up so to speak? Does that make sense?
Any help would be appreciated. Thanks in advance.

 

most of the bed liners ive ever sprayed said to sand the surface and any bare spots with rust etc to clean till its shiny and then spray with an epoxy primer...then spray your bed liner according to the tech sheet.

 

Prep the bottom with whatever grit of sandpaper the instructions say. You can smooth out the missing areas by putting the sandpaper on a little rubber block and sanding in a "crosshatch" pattern: sand in an X. Longer strokes will smooth it out more evenly. If you want, you can go a couple of grits courser to begin with, just make sure to stage it up afterward. 180 grit is probably the coursest you should ever need to go, unless the instructions say otherwise. Go to your local jobber and buy an aerosol of self etching primer to spray the bare metal areas that you have now created, following the instructions on the can exactly as far as flash off/ drying time go.
I don't know if you're spraying or rolling the product on, but either way here's a tip:
When you have the truck masked, leave about a 1/2" between where the tape line is and where you want the top of your boxliner to be. Run one more piece of tape on top of the tape edge you already have, folding little pull tabs into the end. Taper your film build off near the top so you don't get a big, thick, gross edge, and peel that last piece of tape off at a 90 degree angle to the body immediately after you're done. This will allow the product to lay back down along that edge instead of leaving an edge you could cut your hand on. Leave the truck masked overnight to minimize the risk of smearing/ accidentally touching the boxliner.
Good luck!

 

Thanks so much. Exactly the kind of reply I was looking for. The product is Monstaliner which is roll on, if you were wondering. And thanks for the tip about the top edge, that will help alot. So basically you're saying to sand it as far down as I need to to make it even with the chips, and then hit it with some self etching primer? Sorry I'm just trying to get perfectly clear on this before I go sanding the paint off my truck haha

 

Yes, that's exactly right. No need to sand all the paint off if there's nothing wrong with it. It's just bodywork- you can always fix it if you don't get it right the first time!

 

self etching primer isnt really supposed to be sprayed over any old paint only bare metal..

 

^^ That's right. I neglected to mention that, but you don't want to spray the whols surface with the etch, just dust it on over the bare metal. Usually two light coats

 

This is my experience with roll on herculiner:

-Use a good quality tape to mask off(I've had best results with 3M and avoid frog tape)
-Sand down the "good paint" so that the surface looks dull and rough to give the bedliner a good surface to stick to, don't need to prime the "good paint"
-Sand down the "bad paint"/rusty spots to bare metal, wipe down with a degreaser and prime
-After the primer is ready to paint wipe down the entire surface one more time (primed surface and unprimed) with a degreaser then allow to dry for about 10 minutes
-Be sure the paint above the rockers is masked off well
-begin rolling paint on according to directions depending on bedliner (number of coats probably depends on brand of bedliner)
-remove masking tape after last coat so that a clean line is left and the liner doesn't become attached to the tape
-allow to dry and cure

Adding a coat or two of rustoleum bedliner over herculiner gave me a better finish than the herculiner alone

Edit: Here are some pics of the results

 

yep and you want to make sure the etch primer is completely dry before you top coat it at all...

 

Yeah I knew what you meant haha thank y'all! Luckily I still have a can of self etching primer left over from a previous project.

 

Thank y'all for the tips! I'm using monstaliner which doesn't have quite the texture that most DIY bedliners have. I will definitely let y'all know how it turns out. I plan on doing it when I get back from DC in 2 weeks