weld prep

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I find that the more I prep the metal the better the welds.Well, what I have been using is just a 5" grinding wheel. Really rough. When I look at the other "good" welders here the metal has no rust.So what should I use? I was thinking about buying the 3m roloc wheels and smooth it that way.What does everybody use to prep the metal before welding?
Reply:Originally Posted by pyroracing85I find that the more I prep the metal the better the welds.
Reply:cool. You ever use a 2" 3m roloc?? I am thinking about using it I have them but never tried it. Seems like a nice finish it makes.
Reply:I've used them to clean gasket surfaces doing tear downs, but not for anything weld related. Most of the stuff I weld is bigger. A 2" disk would take FOREVER!My next grinder will probably be between the 4 1/2" ones and the 7" one. I'm thinking either a 5" or 6" Metabo to give me something in between and can use larger cutting disks..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Forever just taking the rust off? I will try it out and let you know how it turns out.
Reply:Taking the rust off means taking it down to shiny silver metal. Not turning a red piece of steel dark black/brown with a gloss. Thats what the wire wheel does. If it's brownish, it's still rusty. That's a typical Noob error. They think if they wire brush it with a grinder and it changes collor the rust is gone. Nope!The only times the wire brush actually "cleans" any thing is to remove the slag (contaminants are in the slag and it's sitting on clean metal usually) or on alum, where it will cut thru the oxide layer and not imbed additional contaminants like sanding will some times..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:As DSW said, Roloc are for gasket prep. If you want another alternative to a grinding wheel, try a flap disc, which will also prep for welding. Be aware, they work faster than you would think, but personally I think a wheel is more cost effective. I think.?"Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:I also like 24 grit fiber discsOLD miller M-295  (AC)Century 230/140 ac/dcVictor torchNot much else but some cheap tools.
Reply:You are talking about 2 different thangs:Joint/metal prep- Grinding wheels, Flap Discs, Sanding discsFinish- Roloc/3m scotch brite etc etc. and Sanding Discs- since you can get them in a Higher grit for a relatively smooth finishEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Yeah, prep is 'kind' of important.  Some processes 'tolerate' crud (some SMAW).  Some processes can not tolerate much of any (GTAW).Because remember, you are welding METAL.  Not welding rust, or paint, or grease, or oil, or dirt.  METAL.So to get a good weld to the metal, you actually need it to be metal.  Wire wheel - knocks off 'loose' stuff.  Good metal underneath some paint?  A wire wheel might be the right tool to remove the paint from the welding zone.  A stainless wire wheel used ONLY for aluminum can be used to help remove the aluminum oxide layer in the weld zone.Grinding wheel or flap disc or sanding disk - removes loose and not loose stuff.  Sanding or ScotchBrite disk/pads can sometimes be used for prep on relatively 'clean' metal, but usually are used more for final finishing (smoothing and blending and graining the piece).  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by Broccoli1You are talking about 2 different thangs:Joint/metal prep- Grinding wheels, Flap Discs, Sanding discsFinish- Roloc/3m scotch brite etc etc. and Sanding Discs- since you can get them in a Higher grit for a relatively smooth finish
Reply:AVOS speed lock discs .I build lab equipment so i rarely if ever deal with rusty metal, but these discs work well. Attached Images
Reply:3m makes discs similar to those except they velcro on and are a rough nappy fabric type. Works well for aluminum but not steelUA Local 598
Reply:I use the crap out of 2" rolocs for small parts.  Seems like the 2" will cut better than the 3".  It's like you can get more pressure on the 2".  It could also be that I run these on a small air die grinder and maybe it doesn't have the power to run the 3" ones like it should.The 3M branded discs are good, but expensive.  I bought a box of the Standard Abrasive (SA) from enco.  I also bought from 'keenestore' on ebay.  Both of these don't hold up quite as well as the 3M brand, but overall they are a better deal.I usually use 50 grit instead of 24 grit.  The grains on the 24 grit seems to be big enough they just get knocked off.  The 50grit hangs in there until you wear the abrasive out.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by pyroracing85Forever just taking the rust off? I will try it out and let you know how it turns out.
Reply:Does anyone else think it strange that the OP, who's been a member for over 2 1/2 years and posted 350+ times, is just now trying to figure out how to prep metal for welding?During that time I have seen numerous discussions about sanding, wire wheels, sandblasting, different discs, flap discs, etc, etc.If there's one thing that I think everyone would agree with it's that "no one method/tool works the best in all situations"Maybe if some of our posters spent a little more time "out in the shop" rather than punching keys on a keyboard, they'd have a better idea of what works for them.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:HaHaha!   now that you mention it. WTF!