Steel question

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I pick up my steel from a local supply house that sort of specializes in drops and the like (logan steel). I usually find what I think is great steel for welding coupons, just for practice. The problem I am running into is that some of this steel has a mill scale on it that is so thick and hard, a 40 grit flap disk won't get it off. I am spending hours grinding coupons. And then some of this steel even after grinding to a bright shiny metal finish and cleaning with acetone, I am still getting terrible bubbling and tungsten contamination. Is there an easier way to prep this steel for welding, or am I better off getting something else for my TIG coupons? The funny thing is that some of this steel will clean up in a jiffy, with just a few seconds of treatment with the flap disk. I had a mixed batch tonight. A couple of coupons cleaned up in under a minute. Others I am grinding away ad nauseum.I decided tonight to order some of the CRS welding kits from the James F Lincoln foundation, just to try them out as an alternative.Miller Multimatic 255
Reply:I tried a Bristle Disc I like. You have to be careful it doesn't snag on something like an edge, they last a long time but aren't tough.
Reply:For $4.50, you get 6 pieces of 1/8th inch 2x4 plates and 2 pieces of 1/4 inch 3x3 plates. All cold rolled. If these work well, I may just keep buying these. Probably no more expensive than buying bristle disks and honestly my time is valuable. if it saves me 10 minutes of grinding, the $4.50 will be work it for that alone.Miller Multimatic 255
Reply:Originally Posted by Louie1961I pick up my steel from a local supply house that sort of specializes in drops and the like (logan steel).
Reply:Some of the high strength low alloy steel grades(A514, A537, A572 for example) are quenched and tempered to have really high strength.  these can have a really thick layer of mill scale on the surface.  A couple tricks for getting this stuff off.  1 - if the mill scale looks flaky and loose, quickly heat it with a rosebud torch.  Move quickly, and the scale will get hot, expand and pop off.  then you can grind normally on any remnants.  The plate shouldn't even be hot when you're done with the torch.2 - buy a large grinder and some grinding wheels.  Flap disks are the wrong tool for the job.  A grinding wheel or a cup stone on a big air grinder will take anything off the steel plate.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Loui soak your coupons in vinegar and some lemon juice overnight and voila, its off by morning. Heres a sample pic.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by weldermikeLoui soak your coupons in vinegar and some lemon juice overnight and voila,
Reply:Originally Posted by DSWHe wants to practice welding, not make salad dressing or marinade his steel.
Reply:Sounds like the easy stuff is cold rolled and the harder stuff as stated above is hot rolled and the extra process. I just sand the snot out of it and get to clean bright shiny metal for tigging. I go to Logan once in a while. I go to a geat local place in Stratford that treats me right. T.J.www.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:I am going to try the salad dressing since the snow has forced me to put my vehicles in the garage and I now have no place to weld until after the storm has passed.Miller Multimatic 255
Reply:I really need a detached workshop.Miller Multimatic 255
Reply:As previously mentioned, flap wheels are terrible for cleaning. They grind faster than grinding disks, but are worth crap for cleaning. Flap wheels tend to just polish the mil scale. Try cleaning paint off of something with a flap wheel. Works for about 5 seconds then loads up. Never tried it, but possibly using WD-40 as a lubricant while grinding similar to grinding aluminum would help prevent loading. I would try using a hard grinding disk and see if that helps. If not, its probably the grade of the steel.There are thousands of grades of steel. Most common are your A36 and 1018. Also a common metal, especially if Logan Steel does machining or supplies machine shops, you get some 12L14, which doesn't weld well at all.John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:If im gonna use a grinder Louie ill show you a pic of what i use when i get home from work. And readily available at Home Depot. 23grit beast. I dont care how tough the scale is, its gone in a instant. Ill snap a pic later for you.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Here ya go Louie. Animal....The Best bud! Home Depot tool section. 24grit. I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Ay caramaba!, Esso es muy macho!!Miller Multimatic 255
Reply:Originally Posted by weldermikeHere ya go Louie. Animal....The Best bud! Home Depot tool section. 24grit.
Reply:Originally Posted by Louie1961I really need a detached workshop.
Reply:Why, so you dont contaminate your salid dressing coupons?