Four Ways to Remove MILL SCALE

[@Welddotcom]

If you have questions about any products used in this video, please email: [e-mail]

[@nicepete3792]

Ok😉

[@jamesharrell4360]

Thank You Sir's

[@Dev_Everything]

I have a question, whats the price for one?

[@ronamer1]

@@Dev_Everything aaaaaan, they didn't answer. why? because these things are over priced. home gamers will never be the consumer for them, and industrial types don't care how much. but, if you have been fabbing for any length of time, you will notice the dingus grinding digs with the grinder instead of grinding at a flat, constant angle. he makes it look like the disc is causing the trouble when it is actually him.

[@Dev_Everything]

@@ronamer1 muratic acid works like a champ

[@OldJoe212]

You can tell he's a salesman... it took him 15 minutes to give us 4 minutes (at most) of information.

[@jemfly1062]

It's astonishing how verbose Americans can be ...

[@richardneel6953]

Thank god we can skip to the end and not listen to bs. How much do the wheels cost?

[@Bettinasisrg]

Ha, I was thinking the same thing!

[@jl1267]

I'm new to this whole thing, and the extra information helped me.

[@Mikey-ym6ok]

Are you complaining after receiving real information on how to do something? I needed how to remove millscale. I got more info than from my teacher who has a hard to e speaking English. Stop whining.

[@98270360]

I knew it was going to be beyond expensive as soon as he said Diamond. Not because it has Diamonds on it, but because of the way he says DIAMOND.. Felt like I was watching a infomercial for some new frying pan..

[@Sebula21]

Best advertisement for Silicon carbide coated abrasives. Thanks i'll try these out.

[@yo.mama100]

No thank you for letting me know what I need to buy 😃 without having to hear these coders go on any further

[@TheMrshawnpaul]

The silicon carbide definitely looked the best to me

[@Fix_It_Again_Tony]

Vinegar. I recently had five HRS skid plates I needed to prep for paint. I tried a flap disc from Diablo which are zirconium according to the website. No dice. I consider myself a patient person, but I don't have patience for that. I hit the web and found HRPO (hot rolled pickled and oiled) steel which is treated in acid (HCl typically) to dissolve the scale and then bathed in oil to prevent corrosion. I only had the garage to use and it was cold out so I had to keep the doors shut so I figured muriatic acid was a no-go. Acid fumes will cause inflammation in your lungs. It can also cause pulmonary edema where your lungs try to dilute the acid by passing fluid through the membranes that absorb oxygen (the alveoli). You drown in your own fluids. I doubt that is fun. My garage is attached. Also I didn't want every metal surface in my garage to corrode. A little more searching lead me to vinegar. Like the stuff you put on your salad. They do make a 6% concentration cleaning vinegar which is stronger than the typical 5% white vinegar. Buy it at the grocery store in gallon jugs. HD wants to rip you off selling it per quart. It should be like $3 per gallon. Stupid cheap. The way it works is the same as hydrochloric acid - it dissolves the scale. Vinegar is acetic acid. It takes longer than hydrochloric, but if you are a home gamer you likely have time. The trick is keeping it in contact with the plate which can be difficult if it has a couple bends in it like my skid plates. The secret is an absorbent wrap like cloth or paper towel. Both would work. Old bed sheets would also work great. I cut open a contractor garbage bag and lined a large, shallow box with it. I lined the bottom with paper towel and wadded them up where the plate wouldn't make contact with the bottom of the box. I put the plate in and lined the top of it with more paper towel. I poured 6% vinegar over the entire thing making sure to saturate the towels completed. I covered it up and came back in 24 hours. I was able to wipe the scale away with a maroon Scotch Brite pad with minimal scrubbing. That's it, it just wiped off. I did this through the week so I was able to do five plates in five days working for about an hour when I got home from my 9-5. Because I had the benefit of time vinegar worked for me. If you have a large HRS plate and you need to remove the scale it will work for you too. If you need to do it faster I think the diamond coated brush presented here is an interesting choice, or you could pay someone to sandblast it. Good luck!

[@keithj30]

Tried it ,it works and works well, shitload cheaper than trying to use flap disks

[@tealkerberus748]

If you were doing that a lot with similar size work pieces you'd use a plastic storage tub or a kids' shell pool or something like that - a plastic container the right size and shape with a lid that fits pretty well. Thanks for the tip, this is something that has been bugging me a lot - and home on the farm, I do expect to be able to work my schedule around letting stuff soak for a while. How do you tell when the vinegar is no longer re-usable?

[@johnbloom1109]

This works but it depends on how thick the piece you are working on is coated with mill scale. Vinegar will take well more than 24 hours (in my experience) trying to remove thick coats of mill scale.

[@fuzzfacelogic789]

Works faster if the vinegar or acid is heated

[@phillhuddleston9445]

Works well on plain old rust too if you can soak it over night. Rinse it off with baking soda when done to neutralize the acid. a Scotch-bright pad after soaking will take off what does not fall off on it's own.

[@maximuslongrod6361]

Anyone else feel that Bob moffat is the hickok45 of welding ?

[@Aint1S]

You mean TIGCup45? Yup! He's the Tim Allen of welding too. You gotta love Bob's work as well as his disposition. If you're going to take a welding test, watch Bob's video of it and I'll guarantee your odds of passing will go way up, it's his infectious positivity.

[@mrmidnight32]

W. Llewellyn accept he actually knows wtf he’s talking about. Hick as much as I love that good ol boy just knows how to pull a trigger and giggle.

[@maximuslongrod6361]

CK_32 weird... that’s how I mig weld too. Trigger and giggle

[@kdk200]

Ahaha woods walk "look over there some mill scale "pulls grinder trigger"

[@darenlindley]

As soon as you said that I knew EXACTLY what you were talking about!! LOL!

[@cfo215]

If the piece is small enough, soak it in vinegar overnight. Then spray with water, dry off with air and then use wirebrush on anglegrinder to get rid of any residue/mill scale left over. I have a liquid storage tote that I keep the vinegar in. the top is cut about 10" from top and slips over the bottom of the tank. Only caveat is to keep the tank far away from any metal you don't want to oxidize.

[@kingdommusic5456]

yep vinegar 48hrs gets it off , or , 2 x 24 hour soaks

[@richardcampbell4506]

Played more like a cheap infomercial than the straight up style I’m used to from this channel.

[@kenc.9067]

But, the banter was funny

[@chriselliott8147]

I have been using a flapper disc for 10 years and I just bought one of those silicone carbide disc. Holy crappy it is a miracle, easy and faster. Great video bob

[@TylerHarney]

How long did it actually last?

[@johnsylvester6734]

Woo Wee!!! After Bob mentioned this diamond cup brush in his FabTech video I asked my welding rep for a price!!!! The answer was outrageous!!! 2-3/4” 270 grit 5/8”-11 hub List --$421.64 Cost--$275.00 That being said I’d LOVE to try one!!!

[@thelikebutton4405]

Damn, that thing better be coated with dia.... Never mind!

[@BrilliantDesignOnline]

There are some cases where a diamond coated wire cup like this would be good, but finally a price from someone, not shockingly NOT from the mfr or salesman or website or eBay or Amazon. I was thinking $150, so I would like to know the lifespan, because a normal cup is not that long...

[@LacklusterSupply]

You still need that spendy slow grinder to use it too

[@themotofixery]

Holy crap! I'll pass! How much was the carbide wheel again?...

[@BrilliantDesignOnline]

@@thelikebutton4405 3 carat diamonds.

[@jaredmism]

Been a metal fabricator /welder for years and this product is just what the doctor ordered for material cleaning prior to welding. My question is can that wire wheel be used to remove smoke and flux from welds or is it too abrasive and will remove reinforcement?

[@bonnivilleblackcherry9745]

We do auto restoration which in turn brings us into the field of sand blasting. Oddly enough most of our money in the sand blasting department is from industrial work needing millscale removed prior to the welding/coating.

[@Mikey-ym6ok]

That's what I use in the shop. Sand blasting is the BEST way to remove mill scale. Makes my tig welds look perrrrty

[@geoffmooregm]

@@Mikey-ym6ok Agreed. It is incredibly fast for large areas. It also gives consistent results. The only down side is the initial cost. My old shop had an industrial booth you could drive in with forklifts and a 100hp compressor. It was like sandblasting with a fire hose. You could leave small delicate parts in the corner and they would get blasted just from the shot bouncing around.

[@24Kev]

Why get rid of it when you can just cover it in *flex tape*

[@Mikey-ym6ok]

Why bother welding. Just use flex tape.

[@mrmidnight32]

I would take this guys advice to heart if he wasn’t selling the product. Clearly he’s got a point but it’s also just a sale pitch.

[@pelweldplus]

I bought both a 2 ½” diameter and a 4” at first I loved it but the second time I used it it came apart. I wasn’t pushing it. I was using a 7000 rpm grinder and the wires were flying off. So at a $120 a pop the love was short lived.

[@Loschh]

Whoa. This is super cool. Thanks for the video. Aerospace welder here. I usually run alumina 120 quick change disks on a dotco. They burn out fast cleaning inconel.

[@ralphr9218]

After watching this video I tried a Warrior 94017, 4 1/2" Polycarbide Abrasive Wheel, sold at Harbor Freight Tools and it worked amazingly well. Super fast without the damage to the metal. I paid $4.79 after using a 20% off coupon.

[@DavidTheCarpenter]

Industrial applications that I have seen (in shipyards) is to sandblast.

[@Mikey-ym6ok]

Yup!

[@lottjohp]

This is for the newbies: I used to buy 4'x8' 11 gauge mild steel sheet with mill scale. I ground the mill scale off with a hard wheel, then smoothed it with a flap wheel, then primed & painted the sh** out of it. Then I discovered acid, but acid has its own problems. I sand blasted it, but air compressor, sand blasting cabinet, media, time, etc...So the search for mill scale removal continued... Then one day I saw some 4'x8' 11 gauge that had NO mill scale & was "good to go". What the hell this stuff?? The old timer said "Oh it's PNO." PNO?? WTFO?? Pickled and Oiled. The best solution for mill scale removal is NOT TO BUY IT in the first place. HTH.

[@leonardpearlman4017]

I saw some 16 ga sheet once that supposedly was "levelled, stretched, pickled and oiled" I think, it was supposedly intended to make furniture. It was scrap when I got it and partly rusted, but really great stuff in the parts that hadn't rusted. I like what you're saying here! Unfortunately in FLorida, everything tends to be or become rusty if you just look away from it for a minute, I think we will always feel the need to do this

[@strangeblacksmith]

Or just buy cold rolled. It's easier to get here, and less work to degrease.

[@TechieTard]

HAHAHAHAHAHA, Cold rolled just isn't that much more when you think about it. You're going to spend it in disk or some other solution, or in cold rolled. Cold rolled doesn't take your time though!

[@mrdavidurquhart]

What's the difference between manufacturer pickling and pickling in the shop?

[@jonahbrame7874]

This was a great video that answers a ton of the questions I’ve had about grinding mill scale. Thank you for putting this out there. It definitely helps.

[@leontrotter2776]

Thanks I really like your Chanel I was in the pipe trades for a long time am retired now but like to play in my shop and the information you put out really helps .

[@ernieengineer3462]

Great video and information. Old welder, new subscriber. Thanks for taking the time to produce these videos. Every trade, hobby, interest, needs a “go-to” guy like you on KZbin. For welding info, you’re it!

[@HEYPHILLI]

Hello good people, still a newbie myself when coming to work with certain materials, this is all good and well, but what is the best way to clean expanded metal sheets? flap disc and grinding wheels will eat through the strands like nothing, the wire wheel works, but the wires gets broken up real fast, and none of them will clean properly between each strand within the expanded metal sheet only the top or bottom surface. is there a better way or is sanding paper the only way? Sorry English is not my home language. Thank you, appreciate the time you spend reading this comment.

[@kevinogden6977]

I’ve been watching your videos for some time now and find them extremely helpful. I do a lot of repair work on tractors attachments dump wagons and basically anything you might find on a large farm. There’s been a bunch of times I’ve been forced to run single pass flux core wire on multi pass welds because it was all I had and mig wasn’t an option due to high winds. My question is could you do a video showing the difference in penetration between multi pass flux core wire and single pass flux core wire on multi pass welds?

[@DavidBrown-tl5yh]

I made a Welding Table out of a piece of 36" X 36" X 1.25" Steel Plate, and another one out of 60" X 40" X 1" Steel Plate. Both had Mill Scale and some rust on them that I needed to get off AND preserve the flatness as best as I could. I knew that high speed was not the answer and that the mill scale was hard and somewhat brittle. If you skimmed over it and POLISHED it, then it was really hard to get off. I decided to "scratch through it" in a very controlled way. I used a Makita Variable Speed Sander/Polisher at the slowest speed (600 RPM?) to turn a 7" Segmented Diamond Cup Wheel and kept the entire wheel in contact with the plate. These are made for grinding Concrete at up to 8500 RPM, and made short work out of the rust and mill scale. The fact that the diamonds are set into Brass Segments, the scratching into the metal was rather slight, but more importantly, by keeping the wheel 100% flat and in contact with the surface of the plate, there were no gouge marks. The diamonds quickly cut right through the Mill Scale. This gave me the desired flat bare steel surface that is ideal for a welding table. A slight spray of WD40 or LPS#2 with a quick wipe helps keep rust away and makes spatter clean-up fairly easy. If I get too many arc strikes, too much spatter, or some rust, a once over with the diamond cup disc for 3 - 5 minuets does the trick. Keep it moving over the entire surface in several directions and you end up with a slight "Cross Hatch Pattern" which actually looks really neat. Just remember, a light touch is all that is needed. Although not excessively loud, use Safety Glasses, Hearing Protectors, and a particle mask for the rust and initial scale.

[@seawalkarrg]

David Brown. I’ve thought using a diamond cup myself. Would a regular angle grinder cause it to glaze up?

[@DavidBrown-tl5yh]

@@seawalkarrg No.... but they are too fast unless you use a small disk about 4" or so. Check to see what is available. This 7" disc is rated at 8500 RPM and most "Mini Grinders" are above 10,000. The slow speed keeps everything cool, prevents vibration and chatter, and makes it much easier to control. I bought the Makita Variable Speed Sander/Polisher and use it as my "Go To" large grinder. Much lighter and less expansive than most 6"+ Grinders. It also works incredibly well at slow speed, with a J Walter or other good quality Flap Disc on Aluminum. Load the disc slightly with wax.... candle wax is great, and you will be amazed at how well it removes aluminum, how much aluminum dust is on the floor, and how long it lasts. I get many hours out of a single disc, which translates into a couple of months of aluminum fabrication work.

[@jdandcoke]

hi David what is the model number of the makita are you using. thanks

[@DavidBrown-tl5yh]

@@jdandcoke The machine that I have is a Makita 9227C 7" Sander/Polisher, which has a 6 position "Speed Limiter" from 600 - 3000 RPM. The trigger is also Variable Speed up to the maximum preset on the Limiter, and it also has "Soft Start" which eliminates sudden starting torque. The NEW Model is a 9237C and has several new features and is a little cheaper than the old model, about $269.00 Canadian on Amazon. This handles a 7" Segmented Diamond Cup Wheel just great. On this for a flap disc, I use a Walter 7" Enduro FleX 15-R-70XX. The XX is 04 for 40 grit, 06 for 60 grit.... up to 12 for 120 grit. As I say, at slower speeds with a slight loading of wax, these will last you for months on Aluminum in most cases and do a fantastic job. I also have a METABO 5" WEV-1500-125 RT Grinder that is also variable speed, 13.2 Amps, 1500 Watts, with a dial to select 3500, 4900, 6500, 7900, 9500, & 11,000 RPM maximum and again with Soft Start but NO Variable Speed Trigger and this being a little smaller and lighter is my "Go-To" Mini Grinder. Not for a Diamond Cup Disc except a smaller 4" - 5" one, it handles a 5" Walter Flap Disc just great. 80 Grit with wax at 3,500 RPM and you are removing Aluminum efficiently with great disc life. BOTH units have an internal "Tach Signal" and will add power if the unit is loaded and slows down, maintaining a constant speed. These units are $250 - 350.00, and a bit more expensive but super high quality and 3 - 5 times the usefulness of fixed speed units. You will also find them much less fatiguing to use with lower speed, vibration, & noise. LOVE THEM!

[@AzzKicker-bz1cb]

@David Brown Thank you for that advice as well! How do you acquire the candle wax??? In block form or from inexpensive candles??? You can respond to [e-mail]

[@BigHayes7771]

Industrial application is just code talk for more than you should pay

[@kf8575]

DIY toot isnt cheap

[@AzzKicker-bz1cb]

@Ken F Neither is ruining new flap wheels getting them filled with mill scale glaze or adding two or three steps to finish before paint and still haven’t struck an arc or welded an inch anywhere! I trained to weld, but have not been able to put that training into work experience. I still know that every minute spent trying to get mill scale off the work piece before welding, is time lost from welding! Not to mention that getting rid of mill scale makes the work surface that much easier to weld and can save getting inclusions or porosity in the weld! I also know that porosity is caused by things other than mill scale, like incomplete fusion, low or wrong cover gasses, low/high temp, slow/fast wire speed, or filler rod progression. But getting one more variable out of the equation can put you leaps and bounds ahead of the game if you’re able to control the other gremlins of welding issues! If I were given an opportunity to get into a welding job where I could advance my skills, I would spend whatever it took to give me a better starting point in the price!!! It’s one sacrifice vs. another! For me, the cost sacrifice is far outweighed by the employability benefits! If I can produce work at or above the requested/required level, then spending more upfront for tools that give me that advantage is absolutely worth the cost!!!

[@lunchboxproductions1183]

Industrial application is code for "not the cheap overpriced power tool branded garbage you get at Home Depot"

[@jrcicirello]

@@AzzKicker-bz1cb here are the prices of the three grits for that diamond stainless wire cup. I hope you are sitting down. EDP#84323 - $956.85 EDP#84325 $719.85 and EDP84322 - $1287.17 I can pay for a lot of labor at those price points. Just sayin.

[@jrcicirello]

here are the prices of the three grits for that diamond stainless wire cup. I hope you are sitting down. EDP#84323 - $956.85 EDP#84325 $719.85 and EDP84322 - $1287.17 You can pay for a lot of labor to finish the surface at those price points. Just sayin.

[@tonyp9179]

Glad to see Tommy Callahan is still around!

[@elijahtaylor8351]

I try to remove mill scale before welding up steel with my everlast welder. It is a pain so thanks for giving me a couple of new ways to get it off.

[@davetruther31]

Man This is great, I have a heck of a time prepping plate over 3/4" because of the hard mill scale that's always on it.. I usually use a hard disc followed up with a flap disc, but it's always a slow process..

[@iceowl]

depending on the hardness of the scale, you can also use a paint stripper disc for about the same effect. it won't work on scale that's as hard as what's in this video, but for tube and flat stock it cleans off the scale instantly and, if you aren't too aggressive with it, won't leave noticeable marks.

[@stephk5255]

Regular grinder rpm or slower like they demonstrated? I'm a beginner.

[@iceowl]

@@stephk5255 regular speed. keep the disc as flat to the surface you're grinding as possible, for the best finish, and so you don't dig in and leave gouges.

[@825mnelson]

I use a muriatic acid bath for small parts to remove mill scale. 15 minutes soak, then water rinse gets it to wipe right off. Thoughts?

[@weldmama]

so would you need then to invest in a variable speed grinder to use these diamond impregnated wire wheels?? the other tests that were done were using a high speed grinder - would be interesting to see how much scale is removed if they were going at the same lower rpm that the diamond one was used for to compare apples with apples. Clearly it would give a better result but maybe some problems could be offset using a variable speed grinder on the other conventional discs?? i.e. how much of a role does the variable speed play in this...

[@leonardpearlman4017]

On a related note, I just started DRESSING the hard wheels with the same diamond dressers that people use for grinding wheels on say surface grinders, or pedestal grinders. A lot of those hard wheels are not so round, so it bounces around when you try to grind, and of course isn't getting good use from the abrasive. SO, I try to LIGHTLY grind on this diamond-impregnated thing, and there's a little storm of abrasive coming off, and presently the wheel is a little smaller but nicely balanced and very smooth in operation. I started doing this for small mounted wheels as for a Dremel tool or a die grinder and just got ambitious. I thought I was going to destroy the wheel dresser, but not at all! No conclusion here, but it seems to help get a nicer job on the grinding, less aggressive though. I got some of these things from China/Ebay, talking about a little block of bronze or hard metal with diamonds in it, maybe there's a handle or a stub to mount the thing.

[@slayerspam]

I grind with the edge of a diamond cut off wheel. Yeah it scratches but it's so fast

[@HaloGamer401]

Or you could just use a 3M "Clean and Strip" disc. They do a great job of eating through rust, scale and paint.

[@t_train3796]

That's what I'm about to do lol

[@rksando1]

For me, the best method has been to use muriatic acid (32% hydrochloric acid). I dilute it down to 10 %. After the treatment, I use phosphoric acid to create a layer of iron phosphate as a rust barrier and prevent instant rust. Paint adheres well to iron phosphate. Sometimes I grind the iron phosphate off with a flapper disc, and sometimes I just weld through it. The difficult part is finding a container to submerge the steel. For steel plate I've used a kiddie pool. For pipe I use pvc pipe. This also works very well for removing rust from pitted steel.

[@rksando1]

@ I've never used full strength because of the fumes, and I've never timed it. For zinc plated nuts and bolts I usually soak for about half an hour. I use it mostly for heavily rusted steel, and the concentration works its way down after repeated use. I recommend trying it on a small piece of scrap and see if 10% takes too long for your needs. The reaction time is also dependent on the temperature. It will work faster in the summer.

[@westernclimber]

A diamond coated wire wheel??? That's friggin revolutionary.

[@stevesanders3992]

Where can I get this in Australia?

[@Welddotcom]

​@@stevesanders3992 shoot an email to [e-mail]. THey'll be able to help you out.

[@andrewerickson6690]

Are you being punny lol

[@RB-sb9nj]

Wait is it for prepping ? Or can you clean table with it ? Like after welding

[@hootinouts]

Really enjoyed this. I hate mill scale. My experience with industrial diamonds was to dress the grinding wheels on surface grinding machines when I was in tool and die making. Heck, the diamond would skim off the aluminum oxide or silicone carbide abrasive like it was nothing.

[@diasahgasparias5991]

Great video and info. I think for most applications a regular grinding wheel or flap disc is fine though especially if you’re careful with it and learn how to use different angles to your advantage. My boss and co workers would roast me for using a fine buffing wheel to remove scale. For powder coating and finer finish work though this is absolute gold because literally any fucking microscopic scratch shows up on powder coated steel. Bane of my existence. Love how many gadgets the industry has in it now but don’t forget to develop skills over time with normal equipment! Plus the outtakes were hilarious, good stuff.

[@woodentooth]

I used old t-shirts soaked in vinegar, let it sit for a day or two. Wiped it clean and hit it with a 80 grit sanding disc. Worked great and it was cheap.

[@CTSCAPER]

Can we get a link to those flap disks that Pferd sells with silicon for mill scale removal? I went to the Pferd website and couldn't find them.

[@1999av6]

Thank you for this video. I am having a first go at removing mill scale........this stuff can make you regret life decisions......

[@SamMalcolmShow]

The guys in this video don't want to hear this, but they're adorable with their banter. "We coated these wires in diamonds" "STAHP IT!" What a well done video.

[@jroncallo]

I would like to know what the part number of the 40 grit 4.5" silicon carbide coated wheel he was using is. I cant seem to find this anywhere.

[@mrt9749]

Even though I'm not going to buy the diamond brush, I appreciate the information about the silicon carbide. I will just have to do a little more sanding after. Thanks!

[@mbdtw]

I recently found that vinegar removed mill scale from small pieces of bar stock. Brushes right off after soaking for a bit. It leaves a dull gray surface finish which can be removed pretty easily with scotchbrite or a surface conditioning pad. This has saved me sanding/polishing time. Don't know how this affects the metal on a deeper level or weld quality/strength.

[@CraftwerksMC]

Mike B I’ve read info that reports that acidic processes used for removing milscale can cause the steel to become brittle but I do not know for certain. I was told by a fellow that does metal work he uses a 5 gallon bucket of muriatic acid and I’ve tried it to see. It works but then there is the metallurgy issue

[@Captainfab406]

I've been using vinegar for a few years to remove mill scale when I can't get P&O sheet and plate. I always neutralize with a baking soda water rinse afterwards. I have not noticed any obvious strength differences but a metallurgist may have something to say about it.

[@BillWorden]

​@@CraftwerksMC Acid-Based Removal of Mill-Scale is the ONLY cost-effective (and MUCH QUICKER), method of mill-scale removal. It will NOT affect the metallurgical qualities of HR steel. Acetic Acid 10%, Phosphoric Acid 30% or Muriatic Acid 10-15% will remove ALL Mill-Scale in just a few minutes. Vinegar is about 3% Acetic Acid. Muriatic Acid, a.k.a. Hydrochloric Acid, purchased from a hardware store is typically 31.45% strength, so you would mix it 1:3 or even 1:4 (with H2O). Purchase Phosphoric Acid 98% and/or Acetic or Glacial Acetic Acid 98%. Phosphoric Acid 98% is odorless. Acetic Acid, even at 3% Strength smells like vinegar (obviously), and Muriatic Acid 31.45% will knock your D**K in the Dirt. It smells awful! BUT!...When mixed with Water at 1:3 or 1:4 Ratio, has no discernible smell. Muriatic Acid, even at 10% Strength however, needs to be covered to prevent the off-gassing from rusting any ferrous metal within 50-75 ft. The other two acids mentioned do NOT require a cover, nor do any of them have special haz-mat disposal requirements. Phosphoric Acid is used in almost all soft-drinks and that coupled with Carbon Dioxide, is what makes them fizz and have a little 'bite' when you drink or swallow them. All 3 Acids are very safe when used with a little common sense. My favorite is Muriatic Acid & Water. Total Mill-Scale Removal in 15-20 Minutes. Mechanical/Abrasive Removal of Mill-Scale is a Non-Starter. Total waste of time and money, imho. One last thing: Remove the piece/s from the acid/water bath & rinse vigorously with plain water. Then dry with clean, dry, oil-free shop air to prevent flash rust. Shine up if required with an 80-Grit or 120-Grit Flap Disc. Or, if you have a large budget, use a Metabo® or FLEX™ Burnishing Grinder.

[@mbdtw]

I have only done this for small parts that I'm not welding. I like the method because I am putting a blacksmith type finish on them, not painting. Not having to worry about scratch marks and gouges save a lot of time. I thought the education in this video regarding the composition of flap discs and wire wheels was really helpful though.

[@TheDesertRat31]

@@BillWorden here's a question. I need to remove mill scale from some 6 ft angle iron for a table saw fence I'm building. I'd love to use a dilute muriatic solution. If I made a shallow wooden tub and lined it with thick visqueen, do you think that would contain the acid? Thanks.

[@hawkie333]

Love Bob’s accent. I lived in KS for a few years as a kid. I wonder how much better this is than a regular stainless cup brush.

[@9eyeh8chu9]

The absolute best thing ive discovered on my own is a scotch brite style flap disc 4 1/2" for angle grinder

[@MakeItWithCalvin]

Great stuff if you are working a job that can afford that but I would love to see some stuff geared to us budget folks out there. I would love to see a video on comparing various acid methods of scale removal and if they do negatively affect the strength of a weld (hydrogen embrittlement.) For myself I tend to find a nice quick soak or wipe down with vinegar tends to do the trick most of the time for getting the nasty flaky stuff off and then doing a simple solvent wipe and all is good to go for brazing or flux MIG welding.

[@galbar-or7851]

I looked up the price of the diamond wheel and the only place I found had it for over $500 - is that correct??

[@jrcicirello]

For everyone interested in this diamond stainless steel wire cup brush, it will not be available in the US until Feb 2019. The parts numbers will be EDP#'s 84323, 84325, or 84322. This is directly from Pferd customer service conversation on their chat system. Hope this helps.

[@mzahmedofficial5096]

What u start in life to bring better ideas in this profession will bring fruit in future for lots of great workers amazing show again 👍🏼👌🏼

[@ypaulbrown]

Great info...another winner....thanks again Pferd and Bob Moffatt

[@chadandrews98]

Thanks. For Valentine’s I want some industrial diamonds.

[@johnmelzer2576]

This is a great video and provides great detail to the testing but we did very in-depth testing and found that the 3m product line of Scottbrite outperformed everything shown as well on standard equipment meaning you DONT have to change your tooling to "reduced rpm" tooling. Id highly suggest to touch base with 3m and review thier products that we worked with them to refine for shipbuilding.

[@jheissjr]

I'm going to look into 3M like you suggested. Which Scottbrite wheel did you find works well?

[@felixar90]

Mill scale is not what he said. It's just oxides from being exposed to air while hot. It's not "impurities coming out of the steel".

[@ColCurtis]

I agree all the impurities are removed in the steel manufacturing process. He sounds like a typical sales man lots of babble no real facts.

[@memyselfandi8544]

I worked in a smelter. It's exactly what he said it is. Molten metal is much denser than the crap it reacts with, and there's always a layer floating on it that you have to scoop out periodically.

[@felixar90]

@@memyselfandi8544 Mill scale isn't slag/dross . Mill scale forms on the surface of solid red hot steel when exposed to oxygen. It's called mill scale because you get it from hot rolling mills. Also, powdered mill scale + aluminum powder = thermite!

[@memyselfandi8544]

felixar90 Do you have an argument beyond your opinion? Otherwise, the professional gets more credit, especially since I can confirm what he said. Mill scale ain’t just rust.

[@felixar90]

@@memyselfandi8544 It's not my opinion. I work in a fabrication shop and we use tons of hot rolled steel. We also forge stuff and I've seen mill scale being formed right in front of my eyes. If you reduce the mill scale in a thermite reaction, it turns back into iron. I'm also not even one year out of trade school and our shop teacher explained what mill scale was. Did you even look at the wikipedia article? en.wikipedia.org/wiki/Mill_scale

[@frankgrimes8714]

those pferd deals seem to work really well. I am guessing they are priced well above the home dudes budget and nearly impossible to find.

[@nicepete3792]

Love ur videos they help me some on my welding. Im getting a Lincoln welder. Took my other one back. To small🙂

[@m.s.l.7746]

This is BS, no reason for them to cost this much considering the many other products that employ the same technology at (sometimes even precision applied s apposed to this random low tech process). Even worse than them charging ten-twenty times what they should be is the fact that your just trading one impurity for another since diamond will embed in all but the hardest of materials & who knows what kinda issues will stem from the Nickel alloy (what bonds the Diamond matrix to the wire).

[@toolspayless]

Good video, tools are getting better and better!

[@tomherd4179]

Now that was really great information. One thing not covered too much was the grinder speed. All mine are one speed on or off. Guess I was not aware of a variable or two speed grinder.

[@maxprophet2401]

$12 at harbor freight. 2 speeds on and off. Push harder for lower speeds. They're disposable but you can use them a couple times usually. More realistically though they're commonly called polishers and more expensive than a regular angle grinder. I just looked at the big lot stores and they've gotten cheaper it seems. Mine was over $200 years ago but lots of good brands now for less than a 1/3 of that.

[@Welddotcom]

Not cheap... But this is a beast: www.metabo-hpt.com/us/main-navigation/tools?category=/tools/grinders/4-5---5-angle-grinders&title=G3612DAQ6++36V+MultiVolt+Brushless+4-1%2F2-in+Slide+Switch+Grinder+(Tool+Body+Only)

[@tomherd4179]

Thanks for the info. I am going to see what the diamond wire brush costs first, as I am a home hobbyist, but get fustrated removing the mill scale as well.

[@tomherd4179]

Thanks - as soon as I saw the brand I knew $$

[@tomherd4179]

Thanks for the information. Tom

[@HassanBraim]

That was incredibly helpful! Thank you all!

[@rickdenney5772]

Good luck trying to find a part number or product name for the silicon carbide wheel mentioned. I suppose it’s buried on their website somewhere, but I can’t find it.

[@RambozoClown]

Now where can I buy that diamond brush? I see it on Pferd site but no place to buy. Looks like that is only offered in metric thread, too.

[@BrilliantDesignOnline]

Dark Ages company. Why is this not on Amazon???

[@Welddotcom]

shoot an email to [e-mail]. THey'll be able to help you out.

[@KatyLynnWinery]

I am on it. Thank you for presenting this product.

[@adrianprazen23]

I made one of these with dimond wire. Works awesome!

[@thzzzt]

I could have really used the diamond coated wire a few years ago. I was using the 3M Greencorps "flexible" disks and they worked but were still very tedious and labor-intensive. Then I ran into PITTED rust. The only solution for that is sandblasting --or more exactly media blasting. I used coal slag until I found out it contained beryllium, and now they want me to use crushed glass.

[@Dirty-D]

That wire brush didn’t even get into the pitted porous areas of the metal. You can still see all the kill scale. It will contaminate your weld. 🤦🏼‍♂️

[@kenc.9067]

No wonder my standard flap disc doesn't seem to work well. I'm going to get a silicon carbide grinding wheel. By the way, the bloopers and the unscripted banter, especially when the guy's phone rang, were hilarious 😂

[@kenc.9067]

So, I went to my local welding supplier to look for a silicon carbide grinding disc, and they looked at me like I had three heads, lol

[@Bigkuntry5911]

Excellent video, very good information!

[@Aardrijk1]

Was that a standard speed grinder? I wish you would have provided a link for the brush. That thing is a daisy!

[@ShainAndrews]

4.5" Grinder. Figure 10,000-12,000. Agree on providing some links. Their product portfolio is huge. Some things I can find... others not so much.

[@Welddotcom]

The grinder is variable speed. Everything was ran around 11,000 RPM except the cup brush, which was significantly less.

[@westernclimber]

I just downloaded 3 pferd catalogues and couldn't find any diamond wire brushes. Something we might have to phone them about. Unless Bob can get a part # off the demo brush.

[@ShainAndrews]

@@westernclimber Same here.

[@SOLDOZER]

@@westernclimber Just get some Norton Blaze disks. Its not rocket science.

[@hsagri69]

Can these theory's be put to surface rust ect

[@Enonymouse_]

I need this diamond-coated filament cup brush a lot in my shop!

[@AlwaysHopeful87]

What is product number for the silicone carbide disk? Thanks.

[@LocoFabandMachineworks]

I’m assuming the silicon carbide wheel is the same make up as a silicon carbide grinding wheel on your bench grinder for grinding tungsten carbide, if it is Stuff using that anywhere in a 4” grinder. It should be reserved for grinding carbide. Even with a respiratory device dust you crate will get stirred up at a later date and cause you some big problems down the track

[@tonygombas491]

Great video learned so much

[@douglasbernick659]

This is amazing. I need this product. Thanks guys

[@zyxwvutsrqponmlkh]

Lel website has no price. I order nothing that I need to request a quote for. Rug salesmen.

[@zyxwvutsrqponmlkh]

@Abyyss3344 And you gotta wonder what the useful life is like. TBQH there are situations where $100 would not be an absurd price for something like that. Pipeline workers, field repairs and the like, some of these gigs pay well over $100/hr and down time of what ever they are fixing can be orders of magnitude more costly. But regardless it still rubs me wrong when they wont say what it costs. I've been forced to do business with folks that will just pull a quote out of their ass based on what they think you are willing to pay. Highly frustrating.

[@jrcicirello]

@Abyyss3344I posted this a couple of days after this video aired. Someone made a comment to my post yesterday so I started reading other post. Here is the real prices as of the aire date: here are the prices of the three grits for that diamond stainless wire cup. I hope you are sitting down. EDP#84323 - $956.85 EDP#84325 $719.85 and EDP84322 - $1287.17 You can pay for a lot of labor to finish the surface at those price points. Just sayin.

[@jrcicirello]

@Abyyss3344 IKR. I think I can remove that mill scale myself for that kind of money

[@MegaBoilermaker]

Harris (US) and BOC (UK) used to make what they called a "flame cleaning" nozzle that removed mill scale very quickly.

[@joelkrause8694]

Do a video on laser removal, and if there is a possibility of light commercial use

[@BrilliantDesignOnline]

Excellent logic and tool. Too bad no way to actually purchase it... without requesting a quote from a dark ages company..Why is this not available on Amazon or eBay or some other readily available dealer??? The review was great, especially the primer on grinder wheels and flap disks. But I did appreciate John's lightening quick response on the oops phone call: '$500 on Lulubelle in the third' LOL

[@STohme]

Very interesting analysis and very useful discussion. Thanks.

[@TheRoosterCruiser]

With proper safety gear, I’ve put some heavy plate in a tub with swimming pool acid, then rinsed in another tub with baking soda water solution to neutralize. Worked really good, but don’t forget about your parts in the acid, or you won’t find anything left.

[@TrojanHorse1959]

Great video and products guys, thank you!

[@igortretsnom]

I learned something useful today!

[@robertmccracken72]

Pretty neat product. The next question is can I buy without having to give up an arm???

[@ghettobikelife8833]

Generally silicon carbide wears down a lot faster than alum oxide (at least for grinding wheels), is that the case with these flap disks? I always thought the glazing that happens is when the abrasive rubs off at the edges of the individual sheets and leaves it rubbing on the fabric

[@Welddotcom]

No, it will actually last longer, because it won't load up and you won't need to put your weight into it.

[@elisefrank5921]

if you disliked this video you are insane, this video was so so helpful and informational.

[@ChrisWojnarski]

Thanks for the awesome video everybody. Gonna have to get me one of those wire brush wheels . 🙏🍻

[@martinrichter1596]

I get it has dimons on it, but 38O bucks a pop that's crazy. How long do they last.

[@outofcomms]

I have removed hundreds if not thousands of square feet of mill scale over the years with my industrial media blasting machine. Media blasting mill scale is the ultimate removal machine.

[@arekingi]

Oh man, kudos to you guys for producing this video! I'll definitely be purchasing either #3 or #4 for myself, depending on what is easily locally available to me here in NZ. Removing mill scale is the worst! Till now the best I have found is using a high grit paint removal disk... still clogs up like every other option, but with enough time and pressure ends up the best result. Can't wait to try proper alternatives

[@347chas]

Thank you both, very helpful, now where can i get one of those wire wheels in the UK!

[@MakeItMetal]

Tried calling to tell you that 40 grit flap disc was pretty worn before you started..should have been new for a control sample Bob :)

[@tommccarron324]

I use the edge of my cut off wheel and it does a beautiful job

[@payco1000]

Very good and yes helpful. Specially for a hobbiest like myself.

[@rdanderson12]

Nice! Funny ending too!

[@reddhutchinson2788]

Awesome info!!

[@ltbaldwin]

Where can we get the wire cup??? What ever that link is in the description does not work!!! Give us some help here, WHERE CAN WE GET THAT WIRE CUP???

[@WTFChuk]

Flame descaling seems to be a forgotten method. It works better on heavier scale, and still needs a quick going-over with a flap disk, but where it works it is fairly quick and inexpensive if media blasting is not available.