Mill scale removal questions

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So, I never really remove the mill scale when using my mig. But with the tig welder coming today, I'm obviously not going to have a choice anymore.I've seen threads from zap and other guys on millscale removal but I still had a couple questions.First off, how long would you say you spend removing millscale on smaller projects? It seems like it takes an eternity to do one piece of plate...My other main question is how do you do it without gauging the the steal at all and making the surface uneven? Especially on rounded edges of tubing. I use flap discs, regular grinding discs which seem to take longer and the paint stripping discs I have tried as well but those seem to shred apart quickly life span wise.
Reply:I just use a flap disk carefully, but only a little further than where I will actually weld.On the inside of tubing I use my die grinder.Unless items fit nicely in my blast cabinet - then I blast them If I have a lot of tubing ends to do, I clamp my angle grinder to the table upside down, lay something on the trigger, and rotate the tubing against the flap disk using both hands.(that's in the manual right?? - lol)....hmmm, wonder if I could mount a flap disk to my bench grinder.... Last edited by MinnesotaDave; 09-17-2014 at 11:34 AM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by MinnesotaDaveI just use a flap disk carefully, but only a little further than where I will actually weld.On the inside of tubing I use my die grinder.Unless items fit nicely in my blast cabinet - then I blast them If I have a lot of tubing ends to do, I clamp my angle grinder to the table upside down, lay something on the trigger, and rotate the tubing against the flap disk using both hands.(that's in the manual right?? - lol)....hmmm, wonder if I could mount a flap disk to my bench grinder....
Reply:Originally Posted by BrooklynBravestOk so is it safe to assume when guys have projects with a lot of tubing pieces that look perfectly clean they probably used CRS?For example looking in Dhems thread and Jody Collier's recent video, they both look to have entirely clean bare steel do their projects. I didn't know if people are literally sitting there for a few hours to strip these things down or if they just bought it that way. Stripping just the ends is no big deal...Is it neccesary to do the inside of the tubing of is that just for special applications?
Reply:I was playing at work and took a piece of scrap with heavy mill scale on it and left it in a coffee can overnight with some vinegar and a splash of lemon juice. Heres the results. This may help you on big sheet you want stripped. Just use a spray bottle. The next morning it literally wiped off with a rag.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:That's really cool Mike - I will remember that one Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Muriatic acid which can be purchased at any big box home store is also good for chemically removing scale. I just hit it with a very aggressive flap disc or grinding wheel. It can be a bitch to get off. I typically spend 2 times as long prepping my welding coupons as I do actually welding. It is a huge PITA. I am going to splurge and get the CRS steel kits from the J.F. Lincoln foundation from now on. Kudos to Jody for pointing this one out.  http://www.jflfoundation.com/SearchResults.asp?Cat=44  If you buy 10 or more they are $4.50 each for 8 pre-cut cold rolled coupons. Seems like my time is worth more than that, making these a bargain to me. Especially because I still have to pay for my scrap steel which requires all kinds of prep.Miller Multimatic 255
Reply:Originally Posted by weldermikeI was playing at work and took a piece of scrap with heavy mill scale on it and left it in a coffee can overnight with some vinegar and a splash of lemon juice. Heres the results. This may help you on big sheet you want stripped. Just use a spray bottle. The next morning it literally wiped off with a rag.
Reply:Originally Posted by BD1Hey Mike, that reminds me of the POLLOCK at work that placed odor eaters in his shoes. We never did find him .   Vinegar does wonders. Just be careful if you use it to clean up plated tools. IT WILL remove the plating too.
Reply:Originally Posted by weldermikeI hear ya Bob. I was just playing, when i looked in the can the next day i was like meh, looks like a bust. I took it out and wiped it with a rag and was like Holy Crap! It was just sitting on there loose. Just a good trick to keep on the back burner for future projects. And check out the camo keystones that just came out. Even cooler than the vinegar trick.
Reply:Originally Posted by MinnesotaDaveIncognito I see...people will still point and laugh at the Keystone real beer drinkers spend the big bucks and get Bud light
Reply:Originally Posted by weldermikeC'mon Dave....your from Minnesota. You guys will drink your own piss if it has alcohaul in it  it's the winters, I know they make you insane and nothing goes to waste.
Reply:Originally Posted by MinnesotaDaveAnd the way I use to drink, my pee did still have alcohol in it.  I usually used it for starting fires Pretty handy really, but it made guests uneasy when they came over for BBQ and saw how I started the charcoal...I won't even tell you how the pick-up line went at the bar
Reply:Light gauges tubing is actually hot rolled electrically welded, then the mill scale is pickled off. Heavier tubing usually does not get pickled, but mill scale of tubing is usually pretty thin, and not a problem to buff off. Plate is a different animal, and usually has thicker scale on it. Grinder, or acid removes it from large ares if needed, otherwise buy P&O or CRS.
Reply:Originally Posted by DSWReminds me of the 2nd Ghost Rider and the guy peeing fire...
Reply:Originally Posted by MinnesotaDaveI won't even tell you how the pick-up line went at the bar
Reply:We used to use some kinda metal prep dip at an old job that if you let it soak for 5-10 min at room temp, mill scale and oil would wipe off with a green scotchbrite pad. It burned like h3ll if ya got it on your skin, but according to the msds, was fairly harmless except as a skin irritant or if ya drank it. Not sure of the name though. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:BTW, on the brews, check out Yazoo Brewing. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Do you guys always clean the scale off the inside of tubing when you tig?
Reply:If the material is thin, you have to otherwise the contamination will float through the weld puddleMiller Multimatic 255
Reply:Question about spraying vinegar on rusty metal- if one was planning on painting a metal with a self etching primer after some of the rust was removed, should one then neutralize the acid by wiping it down with say a solution of baking soda followed by a rag dipped in water?MM 211Smith Tru Lite O/A set, Thanks Bob!Lincoln AC-225--But you must not change one thing, one pebble, one grain of sand, until you know what good and evil will follow on that act. The world is in balance, in Equilibrium- Ursula K. Le Guin
Reply:I personally would just rinse with water and possibly denatured alcohol. Alky will absorb any water from the pores in the steel and reduce flash rust. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:No need to neutralize vinegar.  Just rinse with some plain water and dry the steel off (rag, blow gun, etc).  You need to dry off the steel so that:- you don't get "flash rust"- and so you don't have any water on the steel when you go to weld it (water or any other contaminant will mess up welds, to varying degrees).Yeah, prep is often a major part of a welding job.Clean dirt and grease/oil (solvent wash), remove paint and such, remove rust and mill scale, clean again (solvent wash/rinse again), and then maybe get to the actual welding (leaving out cutting and fitting, which are often pretty darn important too).  The best laid schemes ... Gang oft agley ...
Reply:May have missed it but will any type vinegar work or is some better than others.
Reply:Originally Posted by johnrbauerMay have missed it but will any type vinegar work or is some better than others.Thanks
Reply:Reading back through the thread again.... I'd be curious to know what's wrong with the beer can. It doesn't look as if it's eaten into at all. --Nashvegas Welder & MoonRise> Thank you. It's all taken care of. Real quick question for either of you or anyone else.... I've got the entire frame to my new welding table sprayed with vinegar and rubbed down with towels and rinsed. It looked really good until.... I decided to help it along drying and went at it with paper towels. The sun came out again and I can clearly see there are fuzzies everywhere. Any quick way to rid myself of the lint stuck to everything so I can get on with priming the metal? I'd prefer not having to go back at it with a wet towel and then a dry towel. It was real difficult getting the underside of the frame.MM 211Smith Tru Lite O/A set, Thanks Bob!Lincoln AC-225--But you must not change one thing, one pebble, one grain of sand, until you know what good and evil will follow on that act. The world is in balance, in Equilibrium- Ursula K. Le Guin
Reply:The major drawback to wiping things that are not smooth-smooth-smooth with a towel/rag/papertowel is the lint/fuzz left behind.Do that a couple of times and you'll remember to not do that.  Non-contact method of choice for me is spritz down the workpiece with some appropriate solvent (observe PROPER safety precautions, as most metal-working solvents are flammable, dangerous to varying degrees, and so on) and blow it dry with some clean compressed air through a blowgun.Prep work is a major portion of time and effort in:-welding- painting- bodywork- etc  The best laid schemes ... Gang oft agley ...
Reply:If I sprayed muriatic acid on a piece would it have tbe same effect or does it need to soak?
Reply:What about going over it quick with a torch and sing the lint/ fuzz off.
Reply:"Do that a couple of times and you'll remember to not do that." --Some mistakes just aren't fun enough to want to repeat.... lesson learned.  I'm losing daylight and the warm rays of the sun though and I've got a really bad feeling this coming winter is going to be a doozie which is why I'm trying to get everything primed and painted on any day we've got where air temps are above 60° F..... do you think I could hit it up with air from an air compressor? If I have to hose it down with our pressure washer... it won't be dry enough to get a coat of primer on it today. Oh... no hair dryer in the house. Our drywaller borrowed the only one we had and burned it up repairing another dog head hole in one of our walls. I meant to get another one but never got around to it.MM 211Smith Tru Lite O/A set, Thanks Bob!Lincoln AC-225--But you must not change one thing, one pebble, one grain of sand, until you know what good and evil will follow on that act. The world is in balance, in Equilibrium- Ursula K. Le Guin
Reply:Originally Posted by Louie1961If the material is thin, you have to otherwise the contamination will float through the weld puddle
Reply:Decided for making coupons for learning tig, muriatic acid would be the easiest route.I picked up this nifty air/liquid tight screw on bucket lid for $8 locally so I can store the acid safely for repeated use.Last edited by BrooklynBravest; 09-24-2014 at 09:04 AM.
Reply:I have many of the same lids on all my food buckets. good stuff.Miller Multimatic 255