Probably a stupid question but.... Metal prep for primer

[ajlelectronics]

I know the TDS keeps getting mentioned and I understand that but I'm trying to figure out if I need it back to shiny bright steel or is it sufficient to clean it and then scuff it up?

The whole job is as good as the weakest link. If the mill scale is solid and unlikely to let go, then my advice stands. If it is unstable, then fetch it off with a flap disc. However, if it takes such effort to remove the mill scale, it will be fine as a substrate. You can overdo the abrasion too by the way, so I wouldn't go below 80 grit or whatever the TDS says.

 

[chunkytfg]

The whole job is as good as the weakest link. If the mill scale is solid and unlikely to let go, then my advice stands. If it is unstable, then fetch it off with a flap disc. However, if it takes such effort to remove the mill scale, it will be fine as a substrate. You can overdo the abrasion too by the way, so I wouldn't go below 80 grit or whatever the TDS says.

see thats where I was at and came here for advice. The mill scale is not rough and loose, it's just that the metal is black instead of bright. Yes I have some angle iron on it that has some rust spots that I'll deal with but the rest of the gate is just black and I didnt know if I was good to just clean, rough it up and then prime over it.

 

[ajlelectronics]

see thats where I was at and came here for advice. The mill scale is not rough and loose, it's just that the metal is black instead of bright. Yes I have some angle iron on it that has some rust spots that I'll deal with but the rest of the gate is just black and I didnt know if I was good to just clean, rough it up and then prime over it.

The colour matters not, if it is stable, just go for it.

 

[brightspark]

read on https://www.google.com/search?q=does+mill+scale+need+to+be+removed+before+painting&sca_esv=b9319a7481b5b185&sxsrf=AE3TifN0rmq6XuUuVBuvyXLHv0bsU6aBxA:1750620056509&ei=mFdYaNrrHrG4hbIPooSF2QY&ved=0ahUKEwjal-v034WOAxUxXEEAHSJCIWsQ4dUDCBA&oq=does+mill+scale+need+to+be+removed+before+painting&gs_lp=Egxnd3Mtd2l6LXNlcnAiMmRvZXMgbWlsbCBzY2FsZSBuZWVkIHRvIGJlIHJlbW92ZWQgYmVmb3JlIHBhaW50aW5nSABQAFgAcAB4AZABAJgBAKABAKoBALgBDMgBAJgCAKACAJgDAJIHAKAHALIHALgHAMIHAMgHAA&sclient=gws-wiz-serp

 

[badabec]

Flap discs: plenty of flap left but the top layer is blunt. How do you expose the lower layers?

 

[Beeezer]

Flap discs: plenty of flap left but the top layer is blunt. How do you expose the lower layers?

Concrete

 

[pint]

i find a rough 'matte' finish best for jotun, it doesn't stick well to smooth/shiney finishes

also give it a really good de-grease, epoxy doesn't like any oils at all