Hand/block-sand 2011 OEM paint?

DancingEquus

New Member
OK.

Multi part question here... sorta long apologies in advance.

Has anybody block sanded from the start of the initial scuffing process for a full color change? I'm not taking the entire truck all the way to bare metal so, more specifically, before spraying epoxy, to have a little more finesse and sanding "accuracy," block sand OEM newer paint? My truck is a GMC Sierra 2500HD Duramax. 65% of its factory white paint is in good condition.

I have a little Dewalt palm random orbit sander that I have been using with 80 grit on areas where the paint is less then great looking due to numerous rock chips and scratches.

However, I work a LOT on my truck at night when my kiddos head to bed and I can just focus and zone. To be courteous to my neighbors I just tried sanding a bit of clear with my 11" durablock and a half round block for the engine and fender curves with a bit of 180 and I liked the texture and results of that SO MUCH BETTER! I felt it was scuffing quicker, with FAR less burn through... I had more control and my goal is to salvage as much of the good factory paint as possible.. So even on the curves and edges of panels I'm not accidently taking off more paint then nessassary. Pics attached clearly illustrate the difference between the hand sanding front quarter and hood, vs the big adorable dalmatian pattern of me with the orbital and just winging it without my normal amount of obsessive research on the how to's of this stage!!!

So, my question before even spraying the first coat of epoxy: is there anything wrong with prep sanding an entire vehicle using block sanding techniques? If yes, what type of "texture/look/feel should I be aiming for in the sanding finish before I know im ready to spray epoxy? Even though I need the scratches, is block sanding with 180g until smooth feeling under my hand ok/right/wrong? Is it sand 180, until smooth texture with no gloss then jump up to a 320 and block again for more and finer scratches or is leaving it blocked at 180 ok?

I know 80 grit on any bare metal spots... is that a must do using a palm sander? Or can I scuff just those spots with my hand as well?

0 experience and i'm in way over my head, but I'm 2 months in and several thousand deep so win lose or draw i'ma do this regardless. But yeah, I've been searching through every sanding forum, YouTube, or article I can find with no luck finding those particular answers!!!

I have all SPI primers and paints: white epoxy over bare metal spots, body filling anything thats actually dented a tad from the rock chips, 2k primer, epoxy as a sealer coat, SPI's white basecoat... there's more but ill save that can of worms for another day! Any advice would be a lifesaver!!! Thank you!
 

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MDPotter

Active Member
I'm sure someone here has done something similar, so they can chime in but here is what I would do:

Unreduced epoxy will fill 180 scratches if you put on two coats. Nothing wrong with sanding by hand, but to be sure it's all scuffed I would go over it with a red scotchbrite. Once all the paint is sanded/scuffed, I would do this:
1) Spray two coats black epoxy (it will show you any imperfections better than the other colors)
2) Do the filler work within 7 days of spraying the epoxy (as long as it stays in the garage)
3) Block sand the filler, reapply as necessary
4) Spray 2 coats epoxy (black or grey) over the filler spots (or 2K if you don't have any bare metal showing)
5) Block the epoxy/2K
6) If it blocks out well and there is no bare metal or filler showing, spray 2 coats epoxy or 2K over the spots you've been working
7) Sand the entire truck with 600 wet and use red scotchbrite in hard to reach spots
8) Wash the truck with dawn dish soap and water
9) Wax & grease remover the whole truck
10) Spray 1 coat epoxy sealer reduced (1:1:1 mix ratio)
11) Spray two coats base
12) Spray three coats clear

Depending on how much time you have on a given day, you can spray the sealer, base, and clear the same day if you start by 9:00. I wouldn't wait more than 12 hours between sealer and base and base and clear.
 

DancingEquus

New Member
MDPotter thank you for so much detail! I think, looking at my truck and reading your response, I maybe might need to order another gallon of epoxy as I only have 1 gallon of white!!!

So, just to clarify, all of the epoxy-filler-epoxy parts of the process are just for the spots where I am filling correct? I wouldn't spray the entire truck with epoxy until the panel section work is complete and I've got it to where there is no metal or body filler burning through? For the fine tuning work would you recommend sanding with 320 to help avoid burn through during that process?

Obviously, as you can see,, that is still a substantial amount of body that is in need of at least several coats of epoxy and 2k-- should NOT have used that dang palm sander on some of those spots!!! Ugh! Oh well... thats only mess up 755 and counting!! i know ill have at least 900 more goofs before this is said and done!
 

MDPotter

Active Member
No need to respray the entire truck with epoxy when you've only got spots. Now, if the whole truck looks like a dalmatian, then you might as well spray the whole truck. But if you only have a handful of filler spots, I would just hit those spots. Don't mask off those spots and spray to the tape though, just sand a little outside the area and then spray within that sanded area so you don't end up with hard edges.

Maybe you're better off to use more of a finishing filler (more flowable, finer talc, goes on thinner) rather than the typical filler. If you just have small chips or dents then something like seal skin might be a good option.

I don't even use 320 anymore. When I'm doing mass filler work, I start with 80 to knock it down close and then 180 to finish the leveling and then I spray two coats epoxy or 2K over the filler. Even when I'm blocking 2K or epoxy or a finishing filler, I use 180 and then spray two more coats of epoxy or 2K when I'm done blocking. This is my way of ensuring I don't see sand scratches. I'm not good at getting all the scratches out so I just stop at 180 and spray a fresh layer of primer so I can sand with 600 wet prior to sealer.

If I were you, I would finish sanding the whole truck with 180 and red scotchbrite and spray 2 coats of black epoxy on the whole thing. Then look over it closely for low spots or chips and start applying filler. I would use seal skin over the minor imperfections and regular filler over bigger imperfections.

A couple principles/lessons that dictate what I've outlined:
-2K shouldn't be applied over bare metal
-Using black epoxy provides you a pretty good surface to find imperfections (pinholes, waves, scratches) because we all know black shows everything.
-Epoxy has a great recoat window. For you, working on it a couple hours in the evening at a time, epoxy will provide you with more time to get the filler work done. And if you end up with some filler over bare metal, it's okay. This appears to be your next daily driver, not a show truck and it will be just fine.
 

DancingEquus

New Member
Ok I was wondering about that filler thing... I have both 3m platinum plus DTM easy sand filler and a glazing putty called "Icing." I have read so much about putting body filler only over epoxy never to bare metal, that even though 3M's label and directions say you can apply it DTM- I was just going to make sure there was epoxy just in case as to not get any moisture and rust formation..........

Side note: rust is what started this repaint process. 2 tiny bubbles of paint under a ugly plastic black fender flare i removed after purchasing the truck back in oct.2019!!! My perfectionist, OCD, over complicating things by an overwhelming amount of reading and research... has brought me to this point... that back wheelwell arch and fender pic... that started this all!!! So, yeah I've been over paranoid and meticulous about ensuring that I don't have to do this again for a VERY long time!!

Black epoxy is not something I had even considered using given the truck is white.... my previous truck was a black dodge Dakota though so I know EXACTLY whatchya mean about showing everything! I've been shining LED flood lights on this truck to find all of the chips, dents, and imperfections... slooooowwwww going for sure

2k=never on metal good to know!!!! (Rust )

It is my daily driver yes, and I work concrete finishing/foundations and it gets taken over dirt roads and cruddy excavation sites more often then not... so I'm an absolute insane chick for where I'm planning on going with the white base after thats sprayed!!! (Maximum sparkle white pearl intercoat clear, then a pastel yellow xyrallic pearl intercoat to change the white to the pastel yellow color and shine and have sparkle!!!)

Heh- I may have over extended my aspirations, but, I want my big ol' work riggin' to be girly and purrdy
 

MDPotter

Active Member
I'm in construction too and I'm sure by the time it's done it will be the nicest truck onsite by the time you're done. Let us know how it goes.
 

DancingEquus

New Member
I most certainly will :) thank you for the tips I feel WAY more confident on moving forward with the rest of the sanding-- I second guess myself and then get concerned and things sorta come to a pause-- definitely needed that guidance-- and encouragment!! MDPotter, you've been a huge help thank you!
 
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