Blasted f100 body with 70-40 fine coal slag

W

wesf10072

So I am new to this site and have read through several posts. I am looking for some direction on this truck body I had blasted with 70-40 fine coal slag. From what I have read I need to use 80 grit on a DA then clean it with the 700 and 710 grease removers before using epoxy primer. I have a guy telling me to use 180 and a self etching primer but I want to be sure here as I do not want this to be an issue later. thanks
 
You read it right. Nothing beats SPI epoxy, un-reduced, as the foundation for a quality paint job. Superior adhesion and rust protection.
 
I never used coal slag for the media so an additional method of cleaning might be needed, IDK. Others here may have so tips for you.
Some like to was the metal with Dawn soap and water prior the the 700, 710. I have done it that way when the blasting was done by others and who knows what could have been in the media.
 
This is what Shine had to say about this awhile back. I do the same. I have personally epoxied right after blasting with coal slag (black beauty?) and never had an issue. Just blew it off. Also used the Dawn and red scotchbrite method. I don't like that method as much becaue of the flash rust (really hard well water). If I'm using fresh media I just blow it off and epoxy.

shine said:
i use dawn soap to get rid of oil residue from blasting. soap it down , rinse it well ,blow dry and epoxy it. flash rust will not hurt anything . if it is bad scuff it with red scotchbrite then epoxy it .
the blaster ripped you off . he should have rinsed his mess off but most do a shitty job and leave .

This is the thread that was in:
 
Coal slag is actually pretty clean, everything organic in the clinker gets cooked off in a kiln and what is left is mostly silica and aluminum oxide.
 
This is what Shine had to say about this awhile back. I do the same. I have personally epoxied right after blasting with coal slag (black beauty?) and never had an issue. Just blew it off. Also used the Dawn and red scotchbrite method. I don't like that method as much becaue of the flash rust (really hard well water). If I'm using fresh media I just blow it off and epoxy.



This is the thread that was in:
Not sure on brand. So your thinking I can skip the 80 grit on a DA?
 
I used fine coal slag from Tractor supply on my 65 vette project (both metal parts and fiberglass). It worked real well and leaves a nice finish and don't see any need to DA with anything. Unless you think there was dirty or oily air used or if there was some contaminant on the surface, I would think going straight to epoxy would be OK.
 
I use the same air supply to blast that I use to paint so I see no need to wash it. If it’s good enough to spray paint it’s good enough for blasting imho.

I blow it out with a leaf blower and head straight to the paint booth.

I use Black Diamond coal slag from Northern Tool.

Don
 
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