millscale clarification/questions

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Let me preface by saying I read the sicky and did a search, but not sure I found and answer to this question. Previously all of the steel I have been using for weld coupons came from a local big box store or my brother brought home scrap from work. On all of this steel, the scale was pretty easy to get off with a flap wheel. Yesterday I went to a local steel supplier for some drops from their "bargain bin" I picked up a bunch of 1/4 and 3/8ths plate, already cut into various coupon sizes (2x5 inch through 8x8 inch). I cleaned the first coupon (8x8 inch) to brite shiny metal with a flap wheel. One side alone took me about 20 minutes with a 60 grit flap wheel. This is the thickest, gnarliest millscale I have ever seen. It is so think it almost looks like old paint, but it is extremely tough to remove.So here is my question. For welding coupons, for learning SMAW with 6011, 6013, 7014 and 7018 rod, how important is it really to remove the scale? Am I messing myself up if I leave it? And if it must come off, besides abrasives and acids, is there a quicker way to get this stuff off? maybe with the OA torch?Thanks in advance.Miller Multimatic 255
Reply:For learning, I think it is very important to remove as much as possible.  It improves the quality of your practice, and you practice good habits.That being said, get yourself a grinding wheel instead of a flap wheel and you will have a better time removing it.
Reply:here's one way (muriatic or vinegar).  http://weldingweb.com/vbb/showthread.php?t=32280but, really, a grinding wheel is the way to go and the more you use it, the better you get.6011 is made for welding through crap, paint rust mill scale.  You don't need to grind off the scale when running it.6013 yes, you need clean steel.  same with 7014 and 7018.for practice?  well, i got into a somewhat lazy habit and that just wrecks a project.  practice like you want to play the game is probably teh best motto.
Reply:Originally Posted by RodJhere's one way (muriatic or vinegar).  http://weldingweb.com/vbb/showthread.php?t=32280but, really, a grinding wheel is the way to go and the more you use it, the better you get.6011 is made for welding through crap, paint rust mill scale.  You don't need to grind off the scale when running it.6013 yes, you need clean steel.  same with 7014 and 7018.for practice?  well, i got into a somewhat lazy habit and that just wrecks a project.  practice like you want to play the game is probably teh best motto.
Reply:Vinegar works great.  Put a few gallons in a bucket and put all your coupons in it for a day.  When you get them out the mill scale will just wipe off.  Hit it with a wire wheel or flap disk and you're good to go.  Sent from my C771 using Tapatalk