Mill scale thickness is a function of cooling time. Solid shapes cool slower, hence thicker scale. Tube shapes cool faster, so the scale is thinner. I fabricate handrails, and have evolved my processes through trial and error. At present, I use muriatic acid for solid shapes like bar stock and molded cap rail. Since the pieces I'm using are fairly long and I don't relish the idea of buying and storing huge amounts of acid, I use a tank made from pvc rain gutter. It's on a tiltable stand with a ball valve drain at one end. I typically soak the stock for a couple of hours, then drain the acid through a paint filter back into containers. Then I run a couple of rinse cycles. I heat the stock with a torch to about 150 degrees to drive out moisture. I then wire wheel the residue off, followed by a wipe down with wd40. For round tube, I built a roller rack and remove the scale with a belt sander at 120 grit. Square tube is cleaned off with a DA sander. Again, wd40 prevents rust during storage and production. Prior to prime and paint, I wipe off the wd with acetone. Unwipeable areas get a shot of chlorinated Brakleen, which leaves no residue. Comments are welcome. Have a great day!
Excellent! Just what I needed. I am learning to TIG weld and I can only get hot-rolled mild steel to practice on. The grit on flapper wheels blocks up with mill scale and they become useless. 15 mins in a covered container of muriatic acid, wash and dry followed by a rub with a rotary wire brush and Voila! bright clean mild steel. The jugs that muriatic is sold in tend to leak vapour which corrodes other workshop equipment. I store my jug inside a plastic bucket with a tight lid.
Mike Webb me too. Just got a TIG welder a few months ago. Razor Weld TIG 200. Not as easy as MIG, but the challenge has been a blast. Glad the video could help. I keep my bucket outside away from all metal. My buddy Doug made a 10-15 ft pair of angel wings that were all metal. Left open a 1 gallon bottle and the entire pair got a nice patina of rust overnight.
Always add acid to water and never the reverse. I gather this mostly matters for *very* strong acids, especially sulfuric, however it seems worth a tiny bit of planning to avoid a possible problem. When you add water to strong acid, apparently this may be exothermic and the solution may boil very violently, splashing acid. If you add acid to water, the solution is very dilute and the heat released is not enough to vaporize and spatter it. If you are concerned, just use vinegar to start with, which is dilute to start with.
I was removing galvanizing from steel plates this way and it works awesome. He is right on about a respirator. I was doing it outside and relied on the wind blowing it away from me. After a weird gust I inhaled some of the gas. My lungs were messed up for a week. It was actually scary. I thought maybe I had done permanent damage (maybe I did). WEAR A CHARCOAL RESPIRATOR!!!
I make weldable nuts doing this to burn off the zinc coating. It's key to have lots of baking soda on hand to prevent ruining everything and burning your skin.
Mark L. Be very careful with muriatic acid. Protect your lungs with an acid-gas respirator, wear long rubber gloves rated for acid resistance, and have full face shield to avoid getting it in your eyes. Also, I recommend using muriatic acid out doors only. The fumes can rust every steel or iron object in your shop - even tools in tool boxes. As he said, have baking soda or soda ash on standby to neutralize the acidity. Rinse the steel parts in a mix of baking soda and water, or soda ash and water to get the acid off.
Thanks for the tip. I was going to use it tonight to remove the mill scale on a 2'X4'X1/4" plate that I'm planning to use as a welding table top. I was going to use it in my garage with the overhead door open but that seems like a bad idea after you mentioning how it will rust every steel or iron object in my shop. Three roller cabs full of rusty tools does not appeal to me at all. I'll stick to using flap discs and sanding discs on a 4 1/2" angle grinder. Thanks again and thanks ManCraftingTM for the video.
Yes, everything you said is true, but there is nothing better. As long as you use the proper ppe and have a steadfast routine, it's as safe as any other job. One point you did make which is VERY true, do not do this indoors, or in your workshop. It will each anything with iron ions, by that I mean destroy. Best to do it in away from workshop type areas. I do mine on my paved area, so even if I was to spill any, all it will do is clean the slabs 😉
i use Mild Steel pan to lightly fry breads. Over time, it has developed few black thick burnt oil coatings that dont go upon washing as well as scrubbing. Can Muriatic Acid remove those marks?
bob wa great question. I recently had a pan that had been burned with something. I don’t recall what, but I tried a lot of different solutions including oven cleaner. None of it really worked. Maybe I should try Muriatic Acid. Worth a try.
TorTorTalks it's a carbon buildup that occurs when the plasma cutter heats and cools the metal. Sometimes it's so thick it's like insulation on the steel.
TorTorTalks I have to disagree with the above comment. Mill scale is composed of mainly various iron oxides. It is an undesirable by product caused by hot rolling the steel at the factory. Hot steel is easier for the factory to shape than cold rolling. The hot iron in the steel reacts with oxygen in the air forming mill scale. Mill scale negatively effects weld quality and paint durability. It tends to be thicker on steel 1/4" and thicker. Thinner on under 1/4".
Adam Prince thanks for clearing that up. Not sure where I got my info, but it's something I believed to be so for so long that I didn't bother to research. Now I'll take the time.
Luke Hubbard you can it to a concrete guy or a You have to keep it out of doors away from metal. If you have to store it put it in a plastic shed or storage enclosure and give the fumes a concrete block to nibble on. The cement in concrete will neutralize muratic acid fumes to calcium chloride; itself a very corrrosice salt but the calcium in the cement does blot up the fumes. Alternatively set up out of doors downwind from structures and anything metal. Pour the acid into a plastic bucket. Using a wood stick gradually stir in powered laundry detergent until it quits foaming. Select a powdered laundry detergent that is predominantly soda (sodium carbonate) plus degergents, sequestering agents, perfume, etc. The soda reacts with the acid to form table salt and CO2. The fully neutraized miratic acid is essentially saltwater. You can pour it down the sink. No EPA disposal necessary. Acid once used as a pickle has metal salts in it. You can neutralize it but the metal salts remain. You really should EPA dispose it but small quantities? Let your conscience be your guide.
Good advice Luke. Using muriatic acid outdoors and away from your car or any other steel objects is smart. Baking soda also will neutralize the acid, and can be mixed with water to rinse the metal after you are done treating it. I don't know if muriatic acid will harm asphalt, or grass. I would put down a sheet of plastic to protect the ground.
Use baking soda mixed with water to neutralize the acid before disposing. Hydrated lime or soda ash mixed with water should also work. Wear safety googles when mixing the acid with the baking soda or soda ash. If you want to measure the neutrality, you can get PH strips at a drugstore.
sir, hope you dont mind me asking, i have a ms plate 20x25 x 1/4 inch dimension, it took me 3 hours just to grind the bluish black coating on 1 side of it, i dont know it that IS mill scale, it looked like paint but didnt burn like paint when i was grinding it, it was powdery, my question is, if i use your method, would the ms plate still be safe to cook on? im planning to use it as a burger griddle, hope you can help, im a newbi when it comes into these thigs, your vid was very helpful, sad to say i saw it too late ahahaha
Late entry......Spray heavily with vinegar, cover with paper towels, spray paper towels with vinegar, cover with plastic wrap, wait at least 24 hours, and VOILA, no more mil-scale. If it doesnt work just do it over again.....cause you have nothing but time.
Wire wheel does not work. It will just polish it. I build BBQ pits made of hot rolled steel and deal with this daily. Polycarbinate disk (looks like a sponge). Every maker uses a different name like EZ Strip, etc, but they all look the same. Will strip it with ease and wont remove metal.
@@ManCrafting Yes, this is very true. Large industrial metal companies use hydrochloric acid (aka muriatic acid) baths to remove mill scale, it's highly efficient, also incredibly cheap. It's not like making a neutralising bath is expensive either, bicarbonate of soda is very cheap too. Good video.
Or maybe some creativity. Get a 8 foot piece of 4 mil poly. Make a frame of 2x4’s appropriate to the piece. Soak it and cover with another piece of poly.
Manny Yabar it’s personal preference. Straight will remove the mill scale faster. Diluted just means it needs to sit longer. I have the same gallon of muriatic acid in a bucket from this video. It’s probably diluted by 4 gallons of water now and it still works. If I want to rush the process I add a little from a new gallon.
@@ManCrafting In water, the acid is diluted and quite a bit but to neutralize you need to mix the acid with a base and that creates a salt. If you put acid into water, then evaporate the water, the acid concentration goes back up, but if you put a base into an acid the acid and base change into salt water. And of course such a thing can also be dangerous if you dont know what your doing as a violent reaction can occur.
Scott Downey technically you are right. I always have a bucket of water and backing soda to neutralize the parts I put in the muriatic acid. If I was to dispose of the bucket of muriatic acid I’ve used for the past three years I’d use baking soda and water to neutralize it. That said. The amount of acid in the bucket becomes less and less over time. I can tell because it’s taking longer to remove the scale. Also, it’s not necessarily a bad thing to have acid added to soil if it was spilled or poured out. Only in high concentrations in a small area.
Last week, I changed out my batch of acid. The old and slow, nasty, stuff was dumped in a big tote and then I added baking soda a few times. A metal grate kept animals out and it sat outside where it dried out in a few days. It will get dumped in the trash. That batch was 1-2 years old. The new batch will be kept in the plastic container, outside, and plywood on top of the plastic lid to keep animals away. I don't have the space and don't want the acid inside where it will cause rust. I guess people assume you can only use acid once or that after one project the cnc plasma table will disappear and we will no longer have a use for the acid. They are also afraid of everyday items that are no big deal when treated properly, but I'm used to that as it also applies to one of my other rights/hobbies that has a few possible dangers for careless people.
![GEEK TIMË [OFFICIAL AUDIO]](http://i.ytimg.com/vi/ry-6RvkH880/mqdefault.jpg)
Mill scale thickness is a function of cooling time. Solid shapes cool slower, hence thicker scale. Tube shapes cool faster, so the scale is thinner. I fabricate handrails, and have evolved my processes through trial and error. At present, I use muriatic acid for solid shapes like bar stock and molded cap rail. Since the pieces I'm using are fairly long and I don't relish the idea of buying and storing huge amounts of acid, I use a tank made from pvc rain gutter. It's on a tiltable stand with a ball valve drain at one end. I typically soak the stock for a couple of hours, then drain the acid through a paint filter back into containers. Then I run a couple of rinse cycles. I heat the stock with a torch to about 150 degrees to drive out moisture. I then wire wheel the residue off, followed by a wipe down with wd40.
For round tube, I built a roller rack and remove the scale with a belt sander at 120 grit. Square tube is cleaned off with a DA sander. Again, wd40 prevents rust during storage and production. Prior to prime and paint, I wipe off the wd with acetone. Unwipeable areas get a shot of chlorinated Brakleen, which leaves no residue. Comments are welcome. Have a great day!
Great tips. Thanks.
Excellent! Just what I needed. I am learning to TIG weld and I can only get hot-rolled mild steel to practice on. The grit on flapper wheels blocks up with mill scale and they become useless. 15 mins in a covered container of muriatic acid, wash and dry followed by a rub with a rotary wire brush and Voila! bright clean mild steel.
The jugs that muriatic is sold in tend to leak vapour which corrodes other workshop equipment. I store my jug inside a plastic bucket with a tight lid.
Mike Webb me too. Just got a TIG welder a few months ago. Razor Weld TIG 200. Not as easy as MIG, but the challenge has been a blast. Glad the video could help. I keep my bucket outside away from all metal. My buddy Doug made a 10-15 ft pair of angel wings that were all metal. Left open a 1 gallon bottle and the entire pair got a nice patina of rust overnight.
Thank you for the straight forward instruction.
Glad you found it helpful.
Always add acid to water and never the reverse. I gather this mostly matters for *very* strong acids, especially sulfuric, however it seems worth a tiny bit of planning to avoid a possible problem.
When you add water to strong acid, apparently this may be exothermic and the solution may boil very violently, splashing acid.
If you add acid to water, the solution is very dilute and the heat released is not enough to vaporize and spatter it.
If you are concerned, just use vinegar to start with, which is dilute to start with.
Scott Willis that’s correct. Unless your rinsing off acid. In which case it would only be possible if you could dip the part.
I was removing galvanizing from steel plates this way and it works awesome. He is right on about a respirator. I was doing it outside and relied on the wind blowing it away from me. After a weird gust I inhaled some of the gas. My lungs were messed up for a week. It was actually scary. I thought maybe I had done permanent damage (maybe I did). WEAR A CHARCOAL RESPIRATOR!!!
I hope you’re ok. Scarring your lungs is no joke.
I make weldable nuts doing this to burn off the zinc coating. It's key to have lots of baking soda on hand to prevent ruining everything and burning your skin.
Absolutely need to neutralize anything you put in the acid.
Mark L.
Be very careful with muriatic acid. Protect your lungs with an acid-gas respirator, wear long rubber gloves rated for acid resistance, and have full face shield to avoid getting it in your eyes. Also, I recommend using muriatic acid out doors only. The fumes can rust every steel or iron object in your shop - even tools in tool boxes. As he said, have baking soda or soda ash on standby to neutralize the acidity. Rinse the steel parts in a mix of baking soda and water, or soda ash and water to get the acid off.
+Mark Lombard thanks. All good advice!
Thanks for the tip. I was going to use it tonight to remove the mill scale on a 2'X4'X1/4" plate that I'm planning to use as a welding table top. I was going to use it in my garage with the overhead door open but that seems like a bad idea after you mentioning how it will rust every steel or iron object in my shop.
Three roller cabs full of rusty tools does not appeal to me at all.
I'll stick to using flap discs and sanding discs on a 4 1/2" angle grinder.
Thanks again and thanks ManCraftingTM for the video.
Yes, everything you said is true, but there is nothing better.
As long as you use the proper ppe and have a steadfast routine, it's as safe as any other job.
One point you did make which is VERY true, do not do this indoors, or in your workshop. It will each anything with iron ions, by that I mean destroy. Best to do it in away from workshop type areas. I do mine on my paved area, so even if I was to spill any, all it will do is clean the slabs 😉
Shona O'Neill thanks. Interesting to know that’s also the process of choice for industrial operations. Thanks.
Are you mixing the muriatic acid with water? Does it need to be mix with water actually?
It doesn’t need to be mixed unless you want it diluted. I do neutralize the acid on the soaked part in baking soda mixed in water.
Soak in straight vinegar over night. Rinse off with water and dry. Cheap and safe.
I’m guessing you mean like in this video. ruclips.net/video/-4tENY5tBAA/видео.html
i use Mild Steel pan to lightly fry breads. Over time, it has developed few black thick burnt oil coatings that dont go upon washing as well as scrubbing. Can Muriatic Acid remove those marks?
bob wa great question. I recently had a pan that had been burned with something. I don’t recall what, but I tried a lot of different solutions including oven cleaner. None of it really worked. Maybe I should try Muriatic Acid. Worth a try.
I put my skillet into my wood stove on a hot bead of coals. Closed the door and came back later. skillet was as clean and new, ready for a seasoning.
Glenn Franz heat can do it.
I'm very green at welding, what is the purpose of mill scale on steel? Is it to protect the steel
TorTorTalks it's a carbon buildup that occurs when the plasma cutter heats and cools the metal. Sometimes it's so thick it's like insulation on the steel.
TorTorTalks I have to disagree with the above comment. Mill scale is composed of mainly various iron oxides. It is an undesirable by product caused by hot rolling the steel at the factory. Hot steel is easier for the factory to shape than cold rolling. The hot iron in the steel reacts with oxygen in the air forming mill scale. Mill scale negatively effects weld quality and paint durability. It tends to be thicker on steel 1/4" and thicker. Thinner on under 1/4".
Adam Prince thanks for clearing that up. Not sure where I got my info, but it's something I believed to be so for so long that I didn't bother to research. Now I'll take the time.
No problem.
It does sacrifice it self to protect the steel even though you may not want it on there.
can you please tell us the strength of the muriatic acid that you used, and where you bought that grade please? thx
RANDBO it’s just regular Muratic Acid available at Home Depot it Lowe’s. I’ve only seen 2 types, either work.
@@ManCrafting thx for quick reply!!!
I was up late working on an order. If I see a notification, I try to be helpful. Thanks for watching.
@@chadfrommancraftingtm5734 subd
RANDBO thank you.
how do you properly dispose of the muriatic acid once you are done with it? I imagine you can't pour it down the drain straight into the local river!
Luke Hubbard you can it to a concrete guy or a You have to keep it out of doors away from metal. If you have to store it put it in a plastic shed or storage enclosure and give the fumes a concrete block to nibble on. The cement in concrete will neutralize muratic acid fumes to calcium chloride; itself a very corrrosice salt but the calcium in the cement does blot up the fumes.
Alternatively set up out of doors downwind from structures and anything metal. Pour the acid into a plastic bucket. Using a wood stick gradually stir in powered laundry detergent until it quits foaming. Select a powdered laundry detergent that is predominantly soda (sodium carbonate) plus degergents, sequestering agents, perfume, etc. The soda reacts with the acid to form table salt and CO2. The fully neutraized miratic acid is essentially saltwater. You can pour it down the sink. No EPA disposal necessary.
Acid once used as a pickle has metal salts in it. You can neutralize it but the metal salts remain. You really should EPA dispose it but small quantities? Let your conscience be your guide.
Alright great. Thanks for the tips
Good advice Luke. Using muriatic acid outdoors and away from your car or any other steel objects is smart. Baking soda also will neutralize the acid, and can be mixed with water to rinse the metal after you are done treating it. I don't know if muriatic acid will harm asphalt, or grass. I would put down a sheet of plastic to protect the ground.
You can put it back in the bottle and use it again and again until I don't know since I have reused my several times.
Use baking soda mixed with water to neutralize the acid before disposing. Hydrated lime or soda ash mixed with water should also work. Wear safety googles when mixing the acid with the baking soda or soda ash. If you want to measure the neutrality, you can get PH strips at a drugstore.
I would second Mark Lombard's comment. Otherwise, a good system with the three buckets.
If you use 100% pure for 15-20 min. Is it safe to say a 50/50 mix of water and muriatic acid for a half hour would give the same results?
TatorLauncher I’m sure. I’ve used some really old muriatic acid and left it in for hours. It worked just fine.
It can be clean the blackness which come by heat treatment????
It can. Just make sure to neutralize it in water and baking soda so the etching stops.
@@ManCrafting 👍Thanks sir
sir, hope you dont mind me asking, i have a ms plate 20x25 x 1/4 inch dimension, it took me 3 hours just to grind the bluish black coating on 1 side of it, i dont know it that IS mill scale, it looked like paint but didnt burn like paint when i was grinding it, it was powdery, my question is, if i use your method, would the ms plate still be safe to cook on? im planning to use it as a burger griddle, hope you can help, im a newbi when it comes into these thigs, your vid was very helpful, sad to say i saw it too late ahahaha
Bad boy unknown absolutely. This is the same product they use in pools. Just wash it off with water and backing soda and it’s neutralized.
You can use (much slower) vinegar. Vinegar IS food.
Scott Willis Muratic Acid is used to balance the PH in pools. People swim in it. Once washed off it’s gone. Water and baking soda neutralize it.
if your not in a huge hurry you can use 30% vinegar but it takes about 3 hours on a warm day the bonus is its less toxic
I posted a second video on this a few years ago. I should link them.
My parts are too big for these containers
You can also soak rags and wrap in a plastic bag.
Which chemical you can use sir
technical prince AYZ. technical I just use Muriatic Acid like it shows in the video.
Or vinegar, much slower though.
I have to take heavy milscale off of a 4x8 piece of 5/8 inch plate...I can't fit that in a bucket lol
You could spray it diluted and cover with 4 mil poly. Let it sit for an hour. Then wash with water and baking soda.
thanks man good idea@@ManCrafting
chief11893 my pleasure. 🔥👊🏼🔥
Late entry......Spray heavily with vinegar, cover with paper towels, spray paper towels with vinegar, cover with plastic wrap, wait at least 24 hours, and VOILA, no more mil-scale. If it doesnt work just do it over again.....cause you have nothing but time.
You can get plastic sheeting and 2x lumber to make the rim of a shallow tank.
Use a grinder with a wire wheel or buy a sandblaster if you do this kind of thing alot.
Daryn Goodwin I've tried a wire wheel on an angle grinder and a sandblaster. This stuff is unbelievable.
Wire wheel does not work. It will just polish it. I build BBQ pits made of hot rolled steel and deal with this daily. Polycarbinate disk (looks like a sponge). Every maker uses a different name like EZ Strip, etc, but they all look the same. Will strip it with ease and wont remove metal.
@BBQ_Sandwich do you have a link to an example of what you use? I am pretty new to all this and am not sure if I am finding the right things.
Copy and paste this into Google 4-1/2" X 7/8" EASY STRIP AND CLEAN DISC
@@ManCrafting Yes, this is very true. Large industrial metal companies use hydrochloric acid (aka muriatic acid) baths to remove mill scale, it's highly efficient, also incredibly cheap.
It's not like making a neutralising bath is expensive either, bicarbonate of soda is very cheap too.
Good video.
Yea? And if the piece is 7 feet long? I guess I need a 7 foot bucket.
Or maybe some creativity. Get a 8 foot piece of 4 mil poly. Make a frame of 2x4’s appropriate to the piece. Soak it and cover with another piece of poly.
Vinegar works better, is safe to handle, and environmentally friendly.
It definitely does not work better, but if you like using it, keep using it.
@@ManCrafting been using it for years, and I have a manufacturing company. Just saying.
It depends on what you mean by "better". Better how?
Safer to handle and environmentally friendly I can agree with.
HOLY SHIT THANK YOU
I also have a video on using vinegar for removal. Both work. This is faster.
Thanks again, oh would you like to enter in my 250 sub giveaway? I just thought I ask, all the best.
The mix of WHAT? You didn’t say wtf the mix was. Thus this video is completely pointless....
CaptainMyCaptain sorry. I’ll try to do better next time.
The mix of water and muriatic acid.
Manny Yabar it’s personal preference. Straight will remove the mill scale faster. Diluted just means it needs to sit longer. I have the same gallon of muriatic acid in a bucket from this video. It’s probably diluted by 4 gallons of water now and it still works. If I want to rush the process I add a little from a new gallon.
Absolutely shocking. This acid is then dumped back into where? the sewage or drainage? Or waste water where it has to bee dealt with.
Graham Higgins I still use it. This acid becomes neutralized in water. I’ve been using this same acid since the video. Not really that shocking.
@@ManCrafting In water, the acid is diluted and quite a bit but to neutralize you need to mix the acid with a base and that creates a salt. If you put acid into water, then evaporate the water, the acid concentration goes back up, but if you put a base into an acid the acid and base change into salt water. And of course such a thing can also be dangerous if you dont know what your doing as a violent reaction can occur.
Scott Downey technically you are right. I always have a bucket of water and backing soda to neutralize the parts I put in the muriatic acid. If I was to dispose of the bucket of muriatic acid I’ve used for the past three years I’d use baking soda and water to neutralize it. That said. The amount of acid in the bucket becomes less and less over time. I can tell because it’s taking longer to remove the scale. Also, it’s not necessarily a bad thing to have acid added to soil if it was spilled or poured out. Only in high concentrations in a small area.
Last week, I changed out my batch of acid. The old and slow, nasty, stuff was dumped in a big tote and then I added baking soda a few times. A metal grate kept animals out and it sat outside where it dried out in a few days. It will get dumped in the trash. That batch was 1-2 years old. The new batch will be kept in the plastic container, outside, and plywood on top of the plastic lid to keep animals away. I don't have the space and don't want the acid inside where it will cause rust. I guess people assume you can only use acid once or that after one project the cnc plasma table will disappear and we will no longer have a use for the acid. They are also afraid of everyday items that are no big deal when treated properly, but I'm used to that as it also applies to one of my other rights/hobbies that has a few possible dangers for careless people.