Removing Mill oil from metal

[sgo70]

Removing Mill scale from metal

I'm getting ready to spray my car with epoxy primer and realized when I got it up on stands that the underside of the subfloor still has a lot of the mill scale (I think it's called) on it. Is there a chemicle that will remove this before painting or do I have to grind it all off. I can only hold my arms above my head for so long before I'd give up and just paint it.

Sean

 

[Bonehead]

I know it is too late now, but I ususally wire wheel the stick, before I even cut it up.
There is an oil on some materials, usually square tube and pipe. When I get it from the suppliers, I usually use aceitone to take that off. The mill scale is a layer of burnt metal , kind of flakey and grey, usually seen on angle iron, and channel iron. It has to be brushed off.

 

[Gastrick]

I hate removing the mill scale. I have yet to find a really easy way to do it. Grinding, heavy sanding, or wire wheel, and it never seems to give up easily.

 

[sgo70]

another lesson learned.

Back to work I guess, I had been reading about Picklex and thought that would work but I can't even find it anywhere and I hear it's not compatible with some epoxy primers.

Thanks anyways,
Sean

 

[eugene vik]

being its the bottom of the car , cant you sandblast it???

 

[56panelford]

being its the bottom of the car , cant you sandblast it???

That's what worked best for me, that mill scale is tougher than the steel it's covering.

 

[TheTruant]

another lesson learned.

Back to work I guess, I had been reading about Picklex and thought that would work but I can't even find it anywhere and I hear it's not compatible with some epoxy primers.

Thanks anyways,
Sean

Picklex 20 is for putting on bare metal to keep it from rusting. No easy way to go about getting the mill coat stuff off.

 

[hillbilly4008]

Not really mill scale, but how many of you guys get fresh steel covered in oil? They do this from the mill to prevent rust during delivery. Thats the stuff that gets you filthy black when you handle it.

Since paint doenst stick to oil, i usually use a grinder, then some cheap laquer thinner and a rag to wipe it down. Ya never get all of it this way. I was talking to a friend of mine who is also a fabricator and what he sometimes does is leaves stuff outside for a while and lets mother nature wash away the oil. Then he grinds off the rust. Still a pain in the arse.

 

[TheTruant]

Not really mill scale, but how many of you guys get fresh steel covered in oil? They do this from the mill to prevent rust during delivery. Thats the stuff that gets you filthy black when you handle it.

Since paint doenst stick to oil, i usually use a grinder, then some cheap laquer thinner and a rag to wipe it down. Ya never get all of it this way. I was talking to a friend of mine who is also a fabricator and what he sometimes does is leaves stuff outside for a while and lets mother nature wash away the oil. Then he grinds off the rust. Still a pain in the arse.

I always use brake parts cleaner for wiping it clean, it really tears up the oily stuff. Not to mention, if you go to NAPA and buy 3 cases it's close to half price

 

[roddguy1]

The best product to use to get the oil off the steel is a good wax and greese remover from your local auto paint supplier. Brake cleaner, lacquer thinners, varsol, anything like that will leave a film behind and cause problems with your primer and paint.

As for the mill scale....... you can only get that stuff off by some sort of mechanincal means. grinding, sandblasting, sanding. It's a pain.

 

[moronthethrottle]

It is possible to mix hydrochloric acid into your pressure washer and blast it away, but you will need to apply something like lime to nuetralize the acid. For our purposes I still believe flap disc grinders are by far the best.

Surface Preperation guidelines: curecoatings.PDF