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outlawauto 09-16-2010 09:34 PM

aluminum Body semi truck help (Please an Thank You)
Im getting ready to spray a Semi truck and while sanding body down the old paint came off the aluminum rivets and then it transfered that black stuff like you get when polishing to the rest of the body. I tried to keep sand paper changed as much as practial . Using 220 grit on a DA Am going to cover with Omni epoxy then Omni bc/cc. I have read about 90 pages on here and sean nothing like this.
Will a good wash with dish soap then wax and grease remover be good.
Makes 2 I done 1st and last all at one time (I think ) :smash:

millercustomfab 09-17-2010 03:51 AM

Depends on what the black stuff is. Sounds almost like a plastic material, but that wouldn't be right for a truck body. Unless last time it was painted the rivits weren't cleaned well, and there was a lot of road grime under that paint job. I've seen a lot of that on heavy truck paint jobs. Surface is sooooo big that a lot of guy skimp on the prep.

oldBodyman 09-17-2010 08:08 AM

They do sell 'Scotch-Brite' pads for the DA (red or gray), works very well with soap & water, should clean up the mess in short order, just keep it WET and rinse well.

swvalcon 09-17-2010 08:28 AM

I work at a truck bodyshop during the day what I do is take a 1/4 in bolt about 3-4 in long and put three red scuff pads cut in half on the bolt and lock it down tight with a washer and nut so it will fit into a drill. then I use this to scuff panels for final scuff and wash good with wax a grease before paint.Always worked good for me.

outlawauto 09-17-2010 09:39 AM

Thanks going to try the pads bolted together a good wash then wax remover and hope it looks good at 70 mph

Pontiac_Judas 09-17-2010 10:36 AM

Its been a long time since I saw a cab-over/"Optimus Prime". (Well, originally a cab over, anyhow...)


milo 09-17-2010 08:14 PM


Originally Posted by outlawauto
Will a good wash with dish soap then wax and grease remover be good.

Do the W&G (if you must first) then finish with the dishsoap and Ajax and a lot of water rinsing ..

Better yet skip the wax grease spreader stuff all together ...

Runnin'OnEmpty 09-17-2010 08:58 PM

That black residue sounds like aluminum oxide to me,
basically corrosion between the rivets and sheet aluminum.

When final washing, use the DAWN brand of dishwashing
detergent. It's better dissolving grease and also rinses better.

That's a cool armadillo scraper, will it be painted black?

deadbodyman 09-17-2010 09:04 PM

we use the red scuff pads on a da with comet and water....Wax &grease is tricky to use right You soak one rag and apply it then wipe it off BEFORE it evaporates with a clean dry one, it takes two hands...

outlawauto 09-17-2010 09:12 PM

washed with dawn and mean green degreaser today letting air tonight then spraying tomarrow. Here is a rough picture of the job hope to do but im a rookie at this . Its a workin truck as long as it looks good going down the road and my customers know I care I'll be happy. B5 Dodge blue, Panther pink, Plumb crazy purple, and lime green. Going to paint the bumper blue for now till I come up with chrome money $$$

kenseth17 09-17-2010 09:35 PM

I too work everyday in a big rig shop. After 5years(in Oct), I still dislike rivets, and cars don't seem all that big anymore.

I can't really say as I've seen what you are talking about, black that transfers when you sand it. Except on new aluminum parts like side extensions which usually come with an oily coating on them. Usually the corrosion is a salty looking white.
I'd wipe down with some wax and grease remover, and when everythings sanded, get epoxy primer on as soon as possible. Aluminum will still corrode exposed, but can't really see it like on steel. If corroded, paint and primer won't stick. Thats one reason you see so many using etching primer that work with a lot of aluminum, even though I feel its far insuperior to epoxy.
What works pretty good for cleaning up corrosion around rivets is a 1 inch green 3m bristle disk-plastic with the little fingers. It will get up tight to the rivet. Then feather out well with da and prime them (primer applyed smoothly as possible). But you need to do a good job feathering them and prime, or likely you will have rings showing when its painted. Also, be real careful sanding around rivets. If you hand sand with like 220 around a rivet or circle with you da, you will likely see rings or scratches. I don't know why around rivets are so fussy. Your best sanding the flat areas, and where you can get between rivets, but safest to scuff the rest of the paint or primer around rivets with a scuff pad to lessen chances of scratches

deadbodyman 09-18-2010 03:49 AM

if you ever have to strip something with rivits,check out the wire brushes ATS aircraft tool supplies ,they are made just for cleaning around rivits,just throw one in a drill and go to town,very cool stuff those guys have and the body hammers look like works of art ...and are way cheaper than off the snapon truck and make them look like they were made by cave men....They might even have something just for prepping rivits that are already painted.You think a semi has a lot of rivits ??? how would you like to repaint a 747.... :sweat: :sweat:

outlawauto 09-18-2010 08:13 PM

Gitt'en'er done couple strips to add tomarrow then the clear. Can't belive it has came out so far. Few spots not feathered to good around the riviets. I had all the odds stacked aginst me right from the start. 2nd paint job ever, by no means a body man , doing it in the yard and 5 mph wind.

Thanks for everyones help will post finished product tomarrow

sqzbox 09-18-2010 08:35 PM

I am going to totaly spot that truck on the road now that I've seen the stripes and blue paint. :D

KC transportation
Princeton In. operations

deadbodyman 09-19-2010 05:26 AM

I had to stop using news papers ,I kept reading the funnies and never got anything done.... :drunk:

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