Grinding Finishing question

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Hello, I am working on a project that has a piece of 1'x1'x 1/4" steel plate.  I am trying to put a shine on it. I first started off using a wire wheel in my drill but that was to slow.  Then went to a sandpaper flap wheel on my drill which was better but still slow.  Then I went to my angle grinder with a older grinding wheel.  This worked great except I have a bunch of micro planes that would be ok if they had some order, or no order at all to the pattern.  I then went back with the wire wheel in drill and flap wheel which just polished the micro planes.  Then did a twisted wire wheel in my angle grinder.  This worked better but still some chatter in the grinding that I cannot get out.  I am looking for some suggestions to make this look consistant.  Will a new grinding wheel make a difference.  Is there something I am over looking?  Thanks,Nathan
Reply:Getting through the layer of mill scale usually means leaving some sort of mark in the surface.  You can use acid to go through it and then polish with progressively finer abrasives (like sandpaper).  Flap wheels are angle-grinder attachments that fall somewhere between a rigid grinding wheel and sandpaper.  Wire wheels can be more aggressive or less aggressive, as you've seen.  You could take the piece to get it blanchard ground.  But even so, getting an actual shine will require further sanding and polishing.The slow road with the drill and the less-aggressive wire wheel is probably the most economical.Jack OlsenMy garage website
Reply:Flatten with 30-60 grit flap wheelSand with 30-60 grit in one direction (all subsequent cuts will be in this direction)Sand with 80 gritSand with 120 gritSand with 180 gritSand with 240 gritEither sand with 320 grit or move to a buff with tripoli compound or rouge to desired finishIf you sanded in the last step, use the tripoli or rouge with a buff hereThere are no shortcuts.  Polishing is hard work.
Reply:This is the way I would do it.Use a grinding wheel to get the mill scale off of the plate.Technique is important to prevent gouging the plate.The use the roughest BLUE flap wheel on it to flatten it all out.Keep the flap wheel moving and do not sit in one spot.Then use the other grits.AWS certified welding inspectorAWS certified welder
Reply:I've gotten good results on flat pieces with a belt sander and progressively finer belts. Do a pass on the surface, turn the tool 90 degrees and do another pass. Lather, rinse, repeat. For HR steel, start with a coarse belt like 60 or 80 grit and work your way up to finer grits until you're happy with the finish. FWIW, 320~400 will get you a finely brushed finish, slightly flat/matte looking with almost no visible toolmarks, and 600 grit is fine enough that you will start to see your reflection in the surface. You will also want to use lube (either water or a light oil) for the finer grits to prevent clogging. Good luck!
Reply:Shine?  Just how much 'shine' are you looking to get?Shine as in 'this is a shiny piece of metal'?Or shine as in 'this piece of metal doubles as a mirror'?Either way, you are looking at going through a progression of abrasive grits until you get to the level of 'shine' that you desire.  The abrasives used can vary (wire brush is kind of coarse and not very 'cutting', to grinding wheels, to 'sandpaper' either hand moved or via power tools like a belt sander or orbital sander or flap disks, to various finer abrasives such as lapping compounds and polishing compounds).And then you can get past that, by doing things like electropolishing.    The best laid schemes ... Gang oft agley ...
Reply:for a consistent even pattern, assuming that is what your looking for, I'd say to finish it off with a DA, that'll give you the most consistent even finish... how "shiny" you want it to be will determine what grit you should wind up going too...miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I have had very good results with a Flap Disc, not a wheel,  in an angle grinder.I offer three choices: Good, Fast, & Cheap. You may pick two.Hobart AC/DC StikMate LXHarbor Freight AD HoodHarbor Freight Industrial Chop SawDeVilbis 20 Gallon, 5 HP Compressor
Reply:I agree with the flap disc on angle grinder
Reply:put the right acid on it, let it stay on it for the right time.angle grind most of fast. with the acids that done their work it should not take to long. then start going with sand paper.start with a high grid. When you change grid change yur direction aswell.you should look on a forging forum to know how you get the most shiny surface.iforgeiron isa good 1 imo
Reply:Originally Posted by akpolarisI agree with the flap disc on angle grinder
Reply:Originally Posted by FegenbushFlatten with 30-60 grit flap wheelSand with 30-60 grit in one direction (all subsequent cuts will be in this direction)Sand with 80 gritSand with 120 gritSand with 180 gritSand with 240 gritEither sand with 320 grit or move to a buff with tripoli compound or rouge to desired finishIf you sanded in the last step, use the tripoli or rouge with a buff here.
Reply:You could have a machine shop knock the plate down on a Blanchard grinder.  Then use a DA sander with finer and finer paper.  How are you going to keep it from rusting?  Clear coat?Dan
Reply:Originally Posted by FegenbushFlatten with 30-60 grit flap wheelSand with 30-60 grit in one direction (all subsequent cuts will be in this direction)Sand with 80 gritSand with 120 gritSand with 180 gritSand with 240 gritEither sand with 320 grit or move to a buff with tripoli compound or rouge to desired finishIf you sanded in the last step, use the tripoli or rouge with a buff hereThere are no shortcuts.  Polishing is hard work.
Reply:OK, I'll join in on this one - not an expert, just experience from sharpening woodworkingtools (having mirror finish / very sharp), and things like flattening PC CPU heatsinks foroptimum heat transfer I'd agree with everyone and just add/extend on what was saidMost important - whatever you do, keep the tool moving and changing in direction of movement - there's no shine without a flat surface. Since you're aiming at a flat surface and that is not something us humans are very good at unless you have decades of practice/feel for it, you can spray blue or a very fine coat ofwhatever paint you have or whatever you have around that will do  (just a dry mist) so that you have an indication of where you've been (as soon as the paint is gone, don't go there any more). Use water to rinse- if you use anything else, you're in for a big mess (at least my experience)Before you start this, get some ruler/reference with which you can check the surface in case you need to flatten it before hand (if it's not flat/has hills/valleys to start with) and do as above knowing where the "hills" are.There's no way of skipping the grades of sandpaper/whatever you use - you have to finish the whole area with one grade (no paint visible) otherwise when you move to thenext grade, it will take forever to do what you skipped.Don't bother polishing etc if you didn't go to a fine enough grade. When I polish mywood chisels, I can go upto 2000 - then you're looking at yourself in a mirror (but you do that just for fun - there's no other reason for it  )
Reply:reason I recommended a DA sander for finishing is, DA stands for dual action, this means not only does it spin but it also randomly swirls & vibrates,  this eliminates most of the circle marks & produces a more even smooth finish where the rotating of a grinder will cause circular marks & scratches & less even flat finish.....miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Can I back up to the original post and ask just what kind of project this 1'x1'x1/4" steel is for? What kind of finish is "needed" and what kind of finish is "wanted"? This could be a lot more trouble than it's worth. But we don't know yet until  we at least have an idea what it is. Almost anything is possible. Is this parts for NASA or are we trying to put chrome wheels on a Yugo? More information is needed.  Maybe I misread somewhere.