So you wanna paint that truck of yours...Material list

[94C1500OBS]

Could any of you experts out there tell me if I just sanded this down really good, there’s not really any kind of major dents. But is there anything else I need to put on before applying a primer or paint? I believe this truck had some sort of a electro coating or something from the factory that caused paint issues prematurely. As even now, I’ve had large patches of paint just fly off my roof, and then leave exposed galvanized metal. I am the second owner and it looks as if the first owner has had the hood repainted at some point because it’s got no issues at all, other than the shade of white is off slightly from the original, almost looks like Ford Oxford White imo. This is not my daily driver by any means and I probably don’t even put on 1000 miles a year on it, but I don’t want it to rust away either

 

[Caman96]

I see massive loose flaking on bed paint.

 

[Jeepwalker]

Ok....here's the deal: The sealer supplied by the paint company back then was a defective product that wasn't time-tested. There's more to the story but ..let's just say they went the way they did ...not just GM, but Ford and Chrysler. Over time it was discovered the UV penetrated the paint and would break down the surface of the sealer. The sealer which eventually became UV-degraded would become powdery UNDER THE PAINT, and the paint would eventually no longer adhere to the sealer. And the paint and flakes off in nice large sheets! LOL. In fact, if you pull back some of the remaining paint that's flaking off your truck, you'll see a powdery surface if you look carefully at the edges of the sealer.

Lighter colors were affected worse (white/silver/light blue) where UV would more easily penetrate the ligher-color paint and affect the sealer faster ...than darker colors which let less UV through. You'll notice that areas on the tk which get the most direct sun exposure (hood/roof/top of panels) flaked off more & faster than lower areas, which get less direct sun exposure. The reason the trucks didn't rust that much...or that bad was because GM used good galvanizing on the truck panels (in response to the previous Square-body trucks -- which were known as rust-buckets and would literally dissolve before an owner's eyes in the rust-belt, LOL!!!). That's why your truck's roof is rusted more...because the paint left that area back in the 90's...ha ha.

Soooooo..... with all that said, the 'fix' by GM back in the day (Ford & Chrysler too), after losing some class-action lawsuits, was to completely strip the trucks down to bare steel and repaint. Remove the sealer completely. And GM repainted probably millions of trucks through local dealers. There was a Chevy dealer not too far from where I used to work which set up a couple make-shift tarp-tents outside behind the bodyshop and hired extra guys just to deal with the large number of local truck repaints. And I knew a guy who that's all he did there..sand and prep GM OBS pickups ...for a couple yrs in the mid-90's. They'd have guys stripping (sanding) & prepping them in the tents and drive into ...and paint them in the paint booth. There was a masking area before the booth. Then get them out of the booth quick as possible and the next one in. And those 2-tone trucks take 'FOREVER' to mask and paint! Some dealers set up make-shift paint booths (vinyl curtains and a fan in the bodyshop..as an extra paint area) too. It was quite an assembly line that went on for a couple years. White vehicles still often eventually flake off, even today.

If you just sand your pickup truck down to the sealer, you haven't solved the root problem. And the sealer will become powdery again (eventually) and the paint-leprosy-issue will eventually occur again. The "Right" way to do it is to ...and this isn't what you want to hear, but the right thing to do is remove the sealer completely, sand it all off, take all the exterior panels down to bare steel. That's a lot of work, I assure you! But worth it. Then apply a self-etching zinc-chromate primer first, then the primer over that. But since they got rid of the Zinc and the Chromate in the old Zinc-Chromate primers making them not as good (and their cost is eye-watering now too!) ...honestly, in reality, these days most guys/shops will apply an Epoxy or Direct-to-Metal (DTM) 2k primer over the bare steel and work up from there. That's what I would do too. (check the primer specs on what you buy to ensure it CAN be used over bare steel & galvanized metal).

If there's bodywork, you can either do it before priming...or after (i.e. bodywork over the primer). The reason some guys do it OVER the primer is because you'll get better adhesion and better corrosion-resistance. But as I say, a lot of guys apply filler over the steel b/c it's quicker and less primer-waste. Make sure if you go over bare steel, you use filler that is compatible with Galvanized metal (not all are). I really like the 3M Platinum Plus HERE. Sure you can buy cheap stuff at the farm and barn, but you'll regret it ...if you ever use good filler. The cheap Bondo is so awful..you can't make it tack-free IDT. I would avoid it like the plague. I would be astonished if your truck has no dents or minor dings. It's white...they probably just don't show up. Apply a guide-coat over the primer after you spray it, then block it out after it's cured (look those up on Youtube).... to get as straight as possible. If you have dings, they'll be exposed after blocking out the guide-coated primer. Then you can address them with a glazing putty (2-part of course). Good paint is all about what's UNDER the paint. You need a good foundation and a good looking paint job takes time to get right. But you'll also be richly rewarded by taking more time in the bodywork and primer-sanding stage.

Once you have everything ready to paint (final sand to 400#), spend time to mask off as best you can. Apply a single wet-coat of NON-SANDING sealer. Let it become sticky, then apply your base, then clear. Or your Single-stage -- if that's what you're using. The non-sanding sealer isn't mandatory, but it does several things: Creates a base to help deflect solvents outward (to the surface -- gives a better shine), Fills in your sandscratches, Helps the first coat of paint hang better (less potential for runs), Provides a uniform color so you don't get blochiness (you could use a white sealer and use less paint), Allows you to see problems (and fix) before you put on the color coat. A lot of home DIY-guys going cheap skip it, but it's really an important step for a decent refinish job ....IMO. Don't buy the super-el-cheapo sealer. Use whatever is recommended under whatever paint you are using. It's a "System".

Hope it helps. Sorry for the novel. Love to see the finished project when you get there. Few things are more satisfying than a hard-fought paint job you did ...yourself!!

 

[Jeepwalker]

Ok....now on your roof...you have several rust spots. This is going to require some extra work...to get right. Not a lot...but please read below a couple times.

What I would do on the roof is sand the whole thing with 40 grit paper on your DA...80# would work too. Remove all the paint to bare steel. Sand it (and the rust) down as much as you can. Then I would apply something like Evapo-rust, or Rust Oleum Rust Dissolver HERE over the rust and let it sit. Do it in a shop or on a warm day (not in the sun) when it's like 70*, or warmer. It contains phosphoric acid and will literally "eat" the rust away by chemical action -- like magic. Spray it on...brush around. You'll soon see the chemical action going on. Spray more on as needed and brush around to keep it wet and keep active chemical at the surface so it can continue dissolving the rust. Do it until ALL the rust (every spec) is eaten away!! It probably won't take more than an hour. If you try to do it when it's colder, chemical action occurs less (more slowly) in colder temps. So...upper 60's..to 70*+ is best. In a warm shop. Then sponge-off the chemical (so it doesn't wash all over your truck) ...and then wash the roof and scrub with water and maybe a little soap and a brush, as the container says. Maybe wash (neutralize) it a second time, and quickly dry the metal to avoid flash rusting. If you get a little flash-rustback...don't worry about that.

Then let the roof dry completely. Then I would sand it again with your sander with like 180 grit. Some primers don't like to stick to treated metal. So thoroughly sand it. Maybe even wash it off with alcohol too. Then apply your epoxy or DTM primer over it all. You'll need a few coats to fill in the old rust pits. And you'll NEVER have to worry about it rusting back again.

Don't fall for the "miracle" rust-converters or POR15 crap or believe anyone who says those are the products to use. Leave those for youtube beginners and guys who don't mind their shade-tree roll-on paint jobs on their Civics rusting back underneath the paint (bubbling) in a few years. Use a rust-dissolver to 'eat away' the rust completely. It's no more work than the miracle cures. Remove the rust and you'll never have to worry about it again.

 

[Jeepwalker]

To remove your trucks paint... that's a lot of work! I won't kid you. Regardless of what method you choose, it's a lot of work. There really isn't an easy way to strip a truck/vehicle, unless you took your truck to a media blaster...and write out a check for them to take it down to bare steel. Plastic media, Soda ....CO2...or some such method are common. And honestly, considering the work, it might be worth getting a few quotes to chew-on. When you get done with your pickup, you might look back and ask why the heck you didn't just pay someone to do the hard work (easy) for $xyz dollars (because stripping to bare steel is a lot of work). And something else....media blasting if done right would probably leave the factory galvanized coating which none of the mechanical methods will do. That alone MIGHT be worth it! But if you're going to strip the paint yourself, you might consider investing in one of the following tools to lessen the grunt-work:

1) A Mudhog. HERE
This assumes you have access to a 'good' 60-gal or 80-gal air compressor. This might be one of the greatest bodywork tools ever invented! If you never used one you don't know what you're missing. Well worth the money. The first time I used a buddy's, it took me all of 2 minutes to decide I was going to go buy one! And I did...in like a few days! You can strip paint very quickly with 36# or 40#. You can do bodywork ..or rough-out bodywork with various grits of sandpaper as needed with a mudhog ...as they're commonly known as. I've even wet-sanded certain panels (like suburban roofs/hoods) with them...and 400# wet/dry sandpaper, much faster than by hand. If you have a good compressor it would save a TON of time vs using a standard 6" DA sander, and be a good buy.

The only caveat is, using less expensive home-center sandpaper is enticing, but a literal waste of time and money. In my opinion, yer better off buying 3M Green Corps 36# or 40# HERE. Yes, it's very expensive at $3 a sheet, but once you get to steel, it's durability lasts and you can do a whole panel whereas home center paper you'll be changing discs a lot, spending more $$ ultimately. Get some 40# and 80#. Just a suggestion.

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2) Drum Sander. HERE
This is a new tool. If you don't have much of an air compressor, this 120V tool works pretty well and would be a good purchase to quickly strip your truck. It strips paint pretty-darn fast and the drums last a long time. If you think of the cost of the drums vs good quality 3M GreenCorps sandpaper (not cheap...but good), its a cheaper way to strip a vehicle like for a shop, with a drum sander. It's really only good for removing paint, you can't use it much for bodywork or any other autobody purpose. However they're very nice to have around the shop if you do metal fabrication! It leaves a nice surface on metal and Stainless steel, AL.

The downfall is it's heavy. Yer typical high-school youtuber who's doing their first paint job (pretending to be an "expert") ...and extolling the virtues of this tool (after using it for a whole 5 min on a hood!)... won't tell you that holding it for a long time doing the sides of vehicles applying the needed pressure (you have to bear down on it!) is rather taxing on yer arms ..and back! And they kind of skip around on the paint too which adds to the 'taxing' part. Annoying ..but they DO remove paint fairly fast (I'm not going to say a whole lot faster than a Mudhog but a bit faster).

You'll sleep well at night after stripping the side of your truck with one of these! And maybe need a backrub the next morning!! But yeah, it's still a hell of a time-saver over using an old-school 6" DA sander and a good alternative for a 120V tool. Because a mudhog take a decent amount of air..which is why I say you need a good air compressor. I would say a drum sander is about 15% quicker than using a Mudhog. A mudhog is lighter though, and you have more control. More finnesse. Some of those same moronic youtuber-beginners claim drum sanders don't throw off as much dust or aren't as loud as other sanders (that's garbage!). Both the drum sander and a mudhog (gear-drive 8" DA sander) produce plenty of dust and the drum sander gets it all over you! However, nothing in life is perfect..and that's not a deal-breaker. On the plus side NEITHER tool heats up the metal and both are real safe to use. So you won't distort your panels like you would using a rotary sander or angle grinder. I recommend the drum sander if you are under-air'd as a 120V tool for stripping paint. Esp also if you also do metal fabrication and need a good finish.

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3) Rotary Sander.
Like a polisher, etc. A good variable speed polisher like shown below ...with a 0-2000 rpm -- fully variable speed (Important!!) is much slower rotating than a grinder, way more controllable & would be the only rotary method I would suggest as remotely safe. Keep it moving. It would work to remove paint with the right discs. It's a finnesse tool. But one would want to be real careful not to burn (stretch) the metal.

Never use an angle grinder!!!! They spin too fast, create too much heat, and will soon burn (distort) the metal and it'll ruin your panels. Again...never use a grinder! I know everybody has an angle grinder laying around. And for sure there's a video of some 16 year old kid with a crackly voice who sounds convincing using his dad's old Chicago Electric grinder with a flap disc to strip his rusty big-muffler'd Civic before he rolls-on a "Pro" Rust Oleum paint job with an 8" house roller ......but do yourself a favor and don't use an angle grinder to remove the paint off your nice OBS truck. Esp if you say the body is perfect. Use a tool that's gentler on the sheet metal as listed above...or worst case, polisher, if you have one, ..can work good if you keep it moving and don't heat up the metal.

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4) Media Blasting
It would be worth getting a price to see what an industrial outfit would cost to "Safely" blast your truck to bare steel ...with a gentle media or like dry ice. Not sandblasting...for sure a hard No on sandblasting!! That'll ruin your truck panels. You CAN use sand blasting in the odd-shaped "safe" areas like sides of the tailgate, wheel wells, etc..which won't distort. But you may not even need to sand those areas.

Plastic and Soda blasting are messy but they DO work and worth considering. You'll spend more time cleaning up after these. And Soda... requires special after-cleaning ...because primer/paint won't stick to some soda-blasted panels w/o completely removing the fine (almost invisible) soda powder. But that's not a deal-breaker. CO2 or Dry ice, there's no mess. But you need an outfit that has a major big unit to work. A little Temu $59 dry ice blaster straight from Guanjo ...that aint gonna cut it. Most media blasting won't affect trim and the glass either (double-check that). Dry ice, they can do it in your own driveway! Even do the engine compartment! Even remove the undercoating! And do a nice job in the areas that are a PITA like the sides of the tailgate, around the wheelwells, the odd-shape areas that are a bugger to remove the paint. If your DI outfit can remove your car's paint/primers to bare steel, it leaves a perfect surface (no sand-scratches, less primer work!). If your finances support it, writing out a check to a media blaster for a couple hrs work is a great way to 'git-er-dun' so you can skip the long grunt-work part of the job & get onto the more fun paint process.

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5) Chemical Stripper.
These days, the NON-MEK strippers won't do the job. Sure orange stripper smells great...but save your $$. That GM sealer is tough stuff. Seriously. I have a few gallons of the old MEK stripper (the stuff that REALLY works ...but hard on the lungs!) ...and even using that to chemically strip the sealer, which I've done, is time consuming. It takes multiple applications, some scraping, and even after neutralizing you STILL need to run a DA sander over the metal to get the hundred little areas of sealer which didn't come off! That adds up to quite a bit of time. Plus the cost of the stipper! It IS less messy in some ways, no dust, I'll give you that -- if you do it outside with paper underneath. You might as well put the $50+/gal into one of the tools above and do it the 'hard' way.

 

[Erik the Awful]

these days most guys/shops will apply an Epoxy or Direct-to-Metal (DTM) 2k primer over the bare steel and work up from there.

+1. Roscoe's roof was solid brown with rust. I used 60 grit on a DA sander to take it down to bare metal, used 2k primer, then 2k spray filler, and finally 2k gloss black.

 

[Jeepwalker]

Cool! Yeah I saw the roof pics. Hopefully you got it all. You'll know 10yrs from now lol. But for other owners who have that, the Evapo-rust or Rust Dissolver, is a nice trick to eat away all remaining rust in deeper rust-pits (if there are any left over after sanding).

Did you guys repaint the truck already?

Edit: Since the post is a 'sticky' ...I kind of wrote those steps for other owners too, who may not be familiar with different processes or things they could do, if they are thinking of re-doing their truck.

 

[Erik the Awful]

I've already had one chip flake up on it. It was my first attempt at real bodywork, and my welding and finishing was crap. The product and process worked great, it's my skill level that needs improvement.