Stainless Weld Blending / Surface Polishing

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Hello everyone... I can't quite seem to find a good answer on this question by searching the forum.I've got a 10 ga. stainless, flat bottom tank.  The weld is between the bottom and the sides.  I need to grind down the weld (no problem) --- but I would then like to put a good finish on the outside of the tank.  Not quite mirror finish, but not very heavy on the grain.I hear 3M scotch brite is the way to go for a sanitary tank... I went to their page and found that there is a *ton* of options available.Can anyone point me in the right direction... how would you do this... what wheels would you use?I would hate to screw it up!!Thanks!~Chet---------------------------------Miller Dynasty 200DXMiller Spectrum 375 Extreme
Reply:Myself..I'd use the brown scotchbrite on a vibrating sander..Gives you those real small swirls..I'm sure others have other opinions though.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by szymancpHello everyone... I can't quite seem to find a good answer on this question by searching the forum.I've got a 10 ga. stainless, flat bottom tank.  The weld is between the bottom and the sides.  I need to grind down the weld (no problem) --- but I would then like to put a good finish on the outside of the tank.  Not quite mirror finish, but not very heavy on the grain.I hear 3M scotch brite is the way to go for a sanitary tank... I went to their page and found that there is a *ton* of options available.Can anyone point me in the right direction... how would you do this... what wheels would you use?I would hate to screw it up!!Thanks!~Chet
Reply:Sorry, Zap, "others have other opinions"???  NOT HERE at weldingweb!!!I use the brown scotchbrite to rough it down, then the fine red scotchbrite, but also on a jitterbug.  If you've got a 90 degree right angle air grinder, and want to use the Roloc discs, I recommend the "very fine" red.  Nice brush finish, and less aggressive than a belt sander, but takes a little longer.I r 2 a perfessional
Reply:for corners we use cross abrasive pads. they attach to a die grinder and work very well.Owner - Certified Welding & Fabrication / 22yrs in businessSteamboat Springs, Co(970) 879-5491AWS structural shopHMI 70t iron worker2 field trucks specailizing in structural steel, aluminum and stainless steel
Reply:ALL are great suggestions.  I have used the Cross pads, if that's the ones that's like a very dense and hard scotchbrite.  They're great for grinding out ripples or grinding the weld flush.  You can then get some red scotchbrite wheels that are shaped like a bench grinder wheel, but a little softer.  They work great, and while they will grind a small amount, they also leave a nice finish for sanitary items.  From what I hear, they're about $70 each, but well worth it.  They can be put on the LARGE straight grinders.
Reply:Thanks for the suggestions!That dynabrader looks like a great tool --- I'll take a look around here at what I can get local, from everyones suggestions, and update the post with some pictures as I work along.Griding is usually no problem, most of the things I have made have been regular ol' mild steel... this is my first adventure on a full stainless project.Thanks for the help!~Chet---------------------------------Miller Dynasty 200DXMiller Spectrum 375 Extreme
Reply:I build Extraction canopies for commercial kitchens from 0.9mm 304, 316 Dull polish S/Steel, all the welds must be invisible. We grind the weld flush first with a 4 1/2" disc, then use a flap wheel in a fairly slow (700rpm) air drill. The type with scotchbrite in between the abrasive cloth, to remove any heavy initial grinding marks, and to put the grain back in.Done correctly you cannot see where the joint was.
Reply:Thanks ---That's great information!  I'll give that a try.  It seems like it would be more controllable that working solely with a grinder.~Chet---------------------------------Miller Dynasty 200DXMiller Spectrum 375 Extreme
Reply:The cross abrasive pads that we use are not like scotchbrites and are about $6ea.  They are shaped like an X , overlaped , and are made by standard abrasives. Kind of like surface conditioning stars , but looped.Owner - Certified Welding & Fabrication / 22yrs in businessSteamboat Springs, Co(970) 879-5491AWS structural shopHMI 70t iron worker2 field trucks specailizing in structural steel, aluminum and stainless steel
Reply:Originally Posted by IH 392The cross abrasive pads that we use are not like scotchbrites and are about $6ea.  They are shaped like an X , overlaped , and are made by standard abrasives. Kind of like surface conditioning stars , but looped.
Reply:Ok, I took down the weld with a regular metal grinding wheel on an angle grinder... then used an 80 grit flap disc to smooth it out.  I'm waiting on an order of 3M discs... medium and very fine... to finish it out.Now, how about the weld on the inside where the tank walls meet the bottom?  I'm guessing a grinding stone of some type on a straight die grinder --- any preferences?The tank will be holding wine, so the more sanitary, the better!I'll get some pictures up this weekend... 3 day weekend = yard work and some tank legs to weld on!Thanks everyone,Chet---------------------------------Miller Dynasty 200DXMiller Spectrum 375 Extreme
Reply:For removing the sugaring/ Colour from the inside corners we use and acid gel. I'll get the name of it tomorrow
Reply:The scotchbrite wheels that I have used are called unitized wheels. Any abrasive dealer will know what they are.I have also used pickling paste which is an acid that is water rinsable. Makes scotchbrite pad scrubbing by hand use about 75% less elbow grease.
Reply:Chet,Did you get a good finishing process for the outside of the tank?What power tools do you have on hand?I sent you a PM asking about some more specifics of the job.Regards,David3M Tech ServiceAbrasive Systems Division