Black Oxide

[Hardrock40]

I need to remove what I think is called black oxide from some steel plates. These range from 2' square to 20" round x 3/8 thick.

We use them at the plant for moving large valves on stainless steel ball tables. The ball tables get covered in black crap coming off these plates and it is causing a contamination problem.

I wore out a new 4 1/2" Dewalt flap disc on one plate today (60 grit) and had to finish with something else. That disc cost 8 bucks. There will be 30+ of these plates and both sides need to be clean.

Maybe a grinding disc followed by sanding? Rust shouldn't be a problem, the plates stay covered in hydraulic fluid 24 /7. This first one is a trial to make sure they don't rust.

I want to stay away from chemicals. What do you suggest? or any ideas to prevent this contamination would also help. These ball tables are very hard to clean.

[Country Metals]

I'm sure that there are plenty of ways, and here is where secrets are that most will never be told.

I can't picture what you are actually cleaning, but I would say sand/shot blasting is the best way.

Other options are wire wheel, sanding disc, needle descalers, plus harbor freak crap.

[Hardrock40]

I guess what I'm asking would be what sanding disc for a 4 1/2 side grinder would be best to do this. If blasting is cheeper and better guess I'll pass on the job.

I thought it could be removed much easier. Maybe I'll go to the Harbor and see what cheep stuff they have this weekend.

Maybe just maybe someone can save me some time searching?

[MMW]

So what I think your talking about is the mill scale on 3/8" thick plate?

Get a 7" grinder & some type 28 wheels & go to town. If your stuck on using a little grinder then still use the type 28 wheels. Link below but you can buy them from any supply house.

http://www.mcmaster.com/#type-28-gri...wheels/=l5e9t2

[ampedtech]

Hard to take off with hand grinding or sanding operation unless the grit is REALLY course.

I know you said no chem, but I have had great luck with Muriatic Acid, get it from concrete supply 28%. Dose take time.

media blasting will do the job

also consider machine grinding in the realm of Blanchard grinding


Good day to all

[Nathan128]

Wire wheel for the grinder hands down. Or ya a needle scaler

[welderboyjk]

If I understand this correctly you place product on the plates and then move it along the roller tables, correct?
Why not get some new plates made from a different material. P&O (pickled and oiled).
What about sending them out to get shot blasted to remove the scale and then "polish" them up a bit with a flap wheel or disc?

[Hardrock40]

Yes that is correct, and the mill scale as I have learned now, comes off and makes a mess as the product is moved along on the ball tables.

Getting new plates of any kind at this time wouldn't happen. Work is so slow. I also counted over 80 of these tonight, not just 30 like I guessed at.

Having them blasted may be the best way to go. But that leaves me out.

I'll try the wire wheel and type 28 disc. The brick cleaning acid might be to slow and to harsh around here. If I can do each one quick enough, and get the right material's for the job, I'll ask if I can have the job.

Thanks for the information. It will be a week or so as I put the finished one back on our OEM line tonight. There is no way it would rust being soaked in oil but they want to wait and see.

[bayweld]

Yes that is correct, and the mill scale as I have learned now, comes off and makes a mess as the product is moved along on the ball tables.

Getting new plates of any kind at this time wouldn't happen. Work is so slow. I also counted over 80 of these tonight, not just 30 like I guessed at.

Having them blasted may be the best way to go. But that leaves me out.

I'll try the wire wheel and type 28 disc. The brick cleaning acid might be to slow and to harsh around here. If I can do each one quick enough, and get the right material's for the job, I'll ask if I can have the job.

Thanks for the information. It will be a week or so as I put the finished one back on our OEM line tonight. There is no way it would rust being soaked in oil but they want to wait and see.

Sand blasting....soda blasting....