Cruez Posted February 1, 2007 Share Posted February 1, 2007 Got a question... I have been doing the prep work on some Big Bear Chopper builds to be powdercoated... and there is something on the flat steel panels that has me puzzled... There is some type of coating on them that is extremely hard to get off.... When I put a 24 grit disc on it with a die grinder, its like eggs on teflon... it will hardly come off.... even sandblasting it is tough... any clue on what this stuff is ????? Quote Link to comment Share on other sites More sharing options...
Lunar240z Posted February 1, 2007 Share Posted February 1, 2007 any pics? Quote Link to comment Share on other sites More sharing options...
vashonz Posted February 1, 2007 Share Posted February 1, 2007 Some of the hot rolled steel has mill scale on it, its really really hard stuff. When I worked at a tool and die shop some of the die plates had this on them, I think a solution was to use this special really really big mill (multiple rotating heads cutting over a rotating work surface). I don't remember what we used to get it off the smaller stuff, probably just painted over it, we were concerned with functionality, not looks (unlike a chopper) Quote Link to comment Share on other sites More sharing options...
Cruez Posted February 1, 2007 Author Share Posted February 1, 2007 I can get a pic later... but the stuff is dark gray, almost black.. a little thicker than paint and is pretty uniform... almost like it was put on there.. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 1, 2007 Share Posted February 1, 2007 YEP! He hit it on the head, MILL SCALE. Probably something like a 1/8" (0.125") thick or thicker, right? Definately Mill Scale by the sounds of it. Black Magic will take it off, but doesn't leave a nice smooth surface to powdercoat. Try a 4" grinder with a 60 grit flapper wheel, and then clean it up with something slightly finer till you can finish your stuff with some abrasive blasting. Quote Link to comment Share on other sites More sharing options...
73ZCAR Posted February 1, 2007 Share Posted February 1, 2007 Cruez, You can sandblast it off. That's the fastest way. Mike Quote Link to comment Share on other sites More sharing options...
Roostmonkey Posted February 1, 2007 Share Posted February 1, 2007 coldrolled is worth every penny if your under 7ga. Anything betweenr 7ga and 3/8", I only use HRPO (hotrolled,pickled in oil stock) because theres no scale. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted February 1, 2007 Share Posted February 1, 2007 Yup mill-scale. Use a wirewheel grinder or a mediablaster with finer media. I use sodablasting, or ultra fine silicut (Its what ever is thrown into our hopper tank). With the wirewheel on a grinder. you kinda really have to go at it. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 1, 2007 Share Posted February 1, 2007 A grinder usually eats right through that stuff. Quote Link to comment Share on other sites More sharing options...
Cruez Posted February 3, 2007 Author Share Posted February 3, 2007 From what I am hearing... I think it might be the mill scale... Thanks for the info.... (even though its still a PITA to get off ) Here is a few shots of one of the completed Choppers I did that was at the Easy Riders show in Charlotte last weekend.. It was black.... but.. still turned out very nice. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 3, 2007 Share Posted February 3, 2007 Pretty bike. I would sure hate to lay that thing down with all those dagger shaped foot pegs. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 3, 2007 Share Posted February 3, 2007 I found that on some of the steel that I have bought the mill scale actually clogs the flap disk on a grinder. For those pieces I use a knotted wire wheel. It has to be a newer wire wheel too, an older one won't do it. I hate mill scale... Quote Link to comment Share on other sites More sharing options...
2003z Posted February 3, 2007 Share Posted February 3, 2007 would muriatic acid remove it? Awesome work on that chopper, btw Cruez! Quote Link to comment Share on other sites More sharing options...
naviathan Posted February 3, 2007 Share Posted February 3, 2007 Hmmm, I have those forward controls. They were on my sporty and I took them off because they were too heavy and would shift gears for me while I was riding. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted February 3, 2007 Share Posted February 3, 2007 I found that on some of the steel that I have bought the mill scale actually clogs the flap disk on a grinder. For those pieces I use a knotted wire wheel. It has to be a newer wire wheel too, an older one won't do it. I hate mill scale... Ditto that scale just laughs at 60 grit flapper wheel - even a new one. I cant get a wire wheel to take it off but I dont have a new other either. In fact I cant find anything to take it off efficiently. Cameron Quote Link to comment Share on other sites More sharing options...
bschiltz Posted February 4, 2007 Share Posted February 4, 2007 would muriatic acid remove it? Awesome work on that chopper, btw Cruez! I'll bet it would:flamedevi. It'd etch the underlying steel, though. Quote Link to comment Share on other sites More sharing options...
2003z Posted February 4, 2007 Share Posted February 4, 2007 I'll bet it would:flamedevi. It'd etch the underlying steel, though. shouldn't be a problem. I use it for cleaning steel quite often before powdercoating. Its the easiest way I have found. Quote Link to comment Share on other sites More sharing options...
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