Removing mill scale from HR steel

Is there a chemical method to removing mill scale? I'm working with 14ga and
removing mill scale is just time consuming and generally not a fun job. I
hit it with a stone disc to get the majority of it off & then flapdisc to
desired finish. Among other problems is that heat generated from the stone &
flapdiscing will sometimes warp the piece.
Anyone know of a chemical method? How about muriatic acid? Do they make a
"stripper" chemical for steel?
Alternatively, I hope to buy a blasting gun & cabinet soon, what kind of
media should I use to remove mill scale? Would walnut shells do the trick or
will I need something harsher?
Thanks to those who responded to my clearcoating question.
-Tom
Reply to
TT
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I've asked the same question. The answer: A solution of vinegar and salt. Use excess salt. Dissolve as much as you can in the vinegar. If done right there'll be a layer of it in the bottom of the container.
Regards,
Orrin
Reply to
Orrin Iseminger
Sorry, I should have googled google's groups archive before asking this question.
I will surely try the vinegar or vinegar / salt solution.
Thanks and sorry, no more responses needed.
-Tom
Reply to
TT
Had the same problem until I started ordering sheets without slag a few more bucks and well worth it. Replaced my SB cabinet this week with large version from HF retail on sale $199.00 an excellent buy thifty on air at about 9 cfm. Try carbide blasting slag excellent for powder coating about 1/5th the cost of glass beads.
Ken
Reply to
Kenneth A. Emmert
Not challenging the muriatic acid and vinegar/salt suggestions, just surprised that such mild chemical treatments would have any effect, at least w/ some of the HR scale I see. That scale, IIUC, is a kind of oxidation product, and thus pretty stable. The underlying steel itself is *much more* reactive to different breeds of acids, such as nitric, which is probably not available to consumers anyway, not just because of 9/11, but because it is pretty nasty stuff. The suggestions tho are certainly cheap enough to try.
It's interesting that different steels from different plants have really diff. appearances. I remember buying a bit of HR angle iron (approx. 1" x 1/8) that happened to be from Korea at the time. Mills bad-mouthed it alloy-wise, but let me tell you, it had an inside radius of *near-zero*, like arch. alum, w/ zero scale! Had sort of a reddish color, which is how you knew it wasn't cold rolled, also was grainier than CR. Straight and nice. Some of the crap I see today... goodgawd....
Cold-rolled is a nice option, albeit at extra cost, but might be worth the extra $$, depending on how difficult scale removal actually is.
Just in case the OP is still reading.... ---------------------------- Mr. P.V.'d formerly Droll Troll
Reply to
Proctologically Violated©®
Oh yeah, forgot to mention, lest the other suggestions don't pan out, running flat material through a "time saver" (basically a big stationary self-feeding belt sander) will give miraculous results, even a polish w/ the right grits. Pricey machines ($3K used, smallish), not a lot of shops have them.
If the material is suff'ly narrow, you could kluge your own time-saver w/ a 4" belt sander, something I'm eventually going to have to do. ---------------------------- Mr. P.V.'d formerly Droll Troll
Reply to
Proctologically Violated©®
Yes. H Cl ( hydrochloric ) ( Muriatic ) acid works fine. Just did a bunch of small parts at school. The kind sold in the "big box" stors as concrete cleaner, it takes a while to work but does a good job. ...lew...
Reply to
Lew Hartswick
Whaddya know?! The vinegar & salt trick worked.
Soaked for about 12 hours and the mill scale came off with a nylon scrubbing brush.
Awesome.
-Tom
Reply to
TT

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