800 grit on orbital sander?

[12three]

I need to take some bad clearcoat off the roof and hood of a small truck in order to spray some new clear. I have never done this. I want to use a 5in cordless dewalt random orbit sander i have laying around but I cannot find 800 grit 5in discs ... does anyone know where to find them?

Alternatively, I have pneumatic sanders as well, but I do not have a large compressor. I have one of the little California Air 4.6 gallon compressors. I have a never used 6in Campbell Hausfeld DA sander and I have seen 800grit discs for it. Will I be able to use this setup and just go slow or is the compressor totally insufficient for the 6in DA sander?

I also have a 10 gallon tank and a 100ft hose I could plumb in if needed... I would prefer not to plumb it in if I dont have to... I can go slow no problem, I just dont know if the sander will have sufficient power...
I also have a pneumatic straight line sander. I assume it would use even more air, but I dont know. It is a performance tool brand. I also have a performance tool brand 5in pneumatic palm orbital sander as well, but it has the same problem as the cordless sander in that i cant find 800grit discs....

any help is appreciated
thanks

 

[engineer2]

amazon.com will have it.

 

[NYBODYMAN]

Put the 6" discs on the 5" electric sander. You can trim if desired but they should work fine. Just be careful not to break through into the color coat, especially around the edges. I honestly would just sand the entire panels, seal/prime and re-base coat/clear coat versus just trying to sand enough to clear coat. Just curious, why is the CC bad? Is it a factory original paint job that is delaminating or a previous repair job gone bad?

 

[12three]

it is just a 20 some year old GM truck that sat out in the sun. The clear just starts flaking for whatever reason. I have seen it on a lot of GM trucks from that era.
It is primarily only a problem on those two panels and the truck sits around more than it gets used. I just wanted to spruce it up for quick and cheap. The base coat is probably fine.
It is the factory paint. I plan to hit it with the rustoleum crystal clear enamel. if that doesnt turn out ok, i plan to use a 2k clear.

So i have found some 5in discs on amazon. the guy who suggested them also mentioned a foam pad for paint work... but he was referring to the pneumatic sander. I dont know if these discs will work on my dewalt and i dont know if i will need a different foam pad than what comes on the cordless dewalt either... it is a dcw210: https://www.lowes.com/pd/DEWALT-20-Volt-Brushless-Random-Orbital-Sander-with-Bag/1000601423

these discs dont have holes, but the sander does. not sure if that is compatible or not?

https://www.amazon.com/dp/B00HJ6WGZU/?tag=atomicindus08-20

edit: I suppose i could just poke holes in the paper. its amateur hour on my end, i apologize

 

[RTM]

Holes just help with dust collection in my world.

Here are some 800 grit 5” disks , my favorite supplier when stocking up.

Abrasives - Discs - 5" Discs - Page 1 - Klingspor's Woodworking Shop

www.woodworkingshop.com

 

[cjarvis]

You're probably better off sanding it down to rough up the surface and remove the loose clear coat, then re-shooting both the base coat and clear. The base coat is typically very thin and you're likely to sand through it.

 

[12three]

i will do that if it comes to it.
i figure 800 is probably the lowest grit i can use and still keep the factory base coat.

 

[NYBODYMAN]

Sounds like a typical sun-baked GM vehicle. It's only an issue on the roof and hood for obvious reasons. Post some pics. I'd be very surprised if you didn't have to respray base.

 

[dnschmidt]

First point. Your not going to get the job of removing the old clear done with 800 grit paper 220-320 is what you're going to need. Any hope of saving the base you can forget about since if the sun was strong enough to destroy the clear it also completely changed the color of the base.

Second point. 5" 800 grit discs are very common. I get mine from Abrasive Resource or since I'm a commercial customer Klingspor. Once you go above 400 grit you need to use film backed discs as the paper simply glides over the irregularities rather than cutting them off. 3M makes this in 260L. Starcke, which is what Abrasive Resource sells has a film backed material they call Platinum which is in fact Starcke 747 film material and is world class. Sunmight, Mirka, Deerfos, and all the major brands make 5" 800 grit paper but you need to buy this from automotive paint stores not the Home Depot.

 

[PCustoms]

First point. Your not going to get the job of removing the old clear done with 800 grit paper 220-320 is what you're going to need. Any hope of saving the base you can forget about since if the sun was strong enough to destroy the clear it also completely changed the color of the base.

Worth quoting

 

[12three]

thanks for the advice gents.
my new plan is to block sand the roof only by hand to start. it is a regular cab so there aint much there. i am going to try the 800 grit and just take it from there. if i see primer i will throw in the towel. i cant exactly make it worse... if nothing else i have plasti dip... i have the clear plasti dip too. i got it on sale.

i will use the sander(s) on the hood if/when i do it.
will the pad that comes on the dewalt sander be ok for this application?
will my little cal air compressor be enough to run a straight line sander on a hood only? how about the DA? i am ok with stopping/starting 10-15times.

 

[dnschmidt]

Normally you use an interface pad above 500 grit. However this normally happens after you've got 90% of the work done with coarser grits and a firm pad and also after the car has been 2K urethane primed. You can forget about using an airfile or air powered DA with a small compressor. That ain't happening. Car painting is not a poor man's game. The average cost to repaint a car here in Phoenix is about $4,000 dollars. Might get it a little cheaper if you use single stage urethane rather than base/clear but my friend that owns a MAACO just charged a dude with an F250 dually $7,000 and the customer was happy to pay it. Out here in the desert paying this much makes a lot of sense since cars don't rust and can basically last forever. In the rust belt this would be folly.

 

[Wolley]

You definitely don't want to use the straight line sander. Any high spot you will be down to bare metal in no time. First thing I would do is take a blow gun and blow the clear off where it's peeling. Once all the loose stuff is off hand sand with 320 on a flexible block and feather the edges of the intact clear. Then sand the whole panel. I'd hand sand the whole thing if you really think it's possible to save the paint. 400 is really the highest you need to go, especially on a job like this. And if the intent of this job is to make it look better, id leave it as is before using any plastidip junk.

 

[no704]

^^ the above. Might be able to remove more of the clear using a pressure washer.

 

[dnschmidt]

The blow gun/pressure washer trick is absolutely the way to go to start the process. Why grind away and waste sandpaper if you can removed the bulk of the peeling clear prior to even starting the process. Out here in Arizona and blow gun/pressure washer has been the starting point for many if not most repaints.

 

[Walkers]

If you are really going to use 800 grit, just book the entire month to get the job done. It is not going to matter much anyway because rattle can clear coat won’t hold up in that usage for very long.
I would use 220 , automotive grade clear, and be done with it. The color coat is going to look wrong when you are done as the metallic in the paint will shine, and the color will have faded in all the paint, and you will be sanding off the faded layer.

Another option to consider is to sand the roof and B pillars and paint it white like the early 67-72 trucks. gives it a sharp, retro sort of look.

 

[dnschmidt]

We've tried to tell him this but I don't think he wants to hear it.

If you are really going to use 800 grit, just book the entire month to get the job done. It is not going to matter much anyway because rattle can clear coat won’t hold up in that usage for very long.
I would use 220 , automotive grade clear, and be done with it. The color coat is going to look wrong when you are done as the metallic in the paint will shine, and the color will have faded in all the paint, and you will be sanding off the faded layer.

Another option to consider is to sand the roof and B pillars and paint it white like the early 67-72 trucks. gives it a sharp, retro sort of look.

 

[ZRX61]

#800 won't give enough key for the fresh paint/clear.

 

[dnschmidt]

I think we should keep a running scorecard of how many posts we get on the following two subjects:

1) I want to sandblast my car with an air nailer compressor.
2) I want to paint my car cheap.

The answers never change but the questions keep coming.

 

[12three]

thanks again for the tips.
still havent got around to doing it =]
i have powerwashed the loose clear off a few times and plan to do it before sanding.
i did get some 600-800-1000 grit discs for my sander off amazon
the reason why i said i planned to use 800 is because thats what the most knowledgeable guy i had talked to at that point told me to do. he said anything lower than 800 will be getting into the base coat... i figure if i do 800 and i dont like it or if it fails i will remove it and go lower.
this is a midwest truck. dabbling with some 1k on my roof aint going to be the end of the world for me. just to give an idea of where my bar is at here: if i only took gloss black rustoleum aerosol to it twice a year it would look better than it does now and i would be happy with it...