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Has anyone else here used concentrated nitric acid to remove broken taps or drills from aluminum? I tried it for the first time on Friday and it works great.?
The theory behind this is complicated, but basically, CONCENTRATED nitric acid attacks steel but does not attack aluminum. (DILUTE nitric attacks both).?
I was intrigued by this idea when I first learned about it many years ago, so I bought a quart of 67.2% nitric acid.*? But I never needed it until Friday because I'm very careful using taps and drills.?
But on Friday I broke off a #25 drill in one of the final steps of making a special tool holder for my minilathe. (It's designed to hold a single-edged razor blade dead vertical in the tool post). This was originally a piece of aluminum scrap, but I'd already done several operations on it with my shaper and mini-mill, so ruining it at that point would've been a real bummer. This seemed like a time to try the acid.??
So I washed off the part with Dawn dishwashing liquid,? rinsed it well, and blew the hole dry with compressed air. I figured the acid shouldn't have to fight its way through oil to get to the metal and it also shouldn't get diluted because dilute nitric acid attacks aluminum as well as steel. (Both of these precautions may have been needless, but this was my first time so I was being careful).?
Then I used a plastic soda straw to dribble a few drops of the concentrated acid into the hole. Nothing seemed to happen for several minutes and I was getting impatient. So after 10 minutes or so, I used a sliver of the same plastic straw to poke around in the hole and feel if the broken drill was loose yet.??
No, the drill wasn't loose -- it was gone, transformed into black sludge.? I rinsed the part off in cold water and the hole was perfect. I was ready to start drilling again.
There are, of course, other ways to remove steel taps and drills from aluminum, but they all take hours or days. Concentrated nitric acid is fast! (And I don't even know HOW fast. I discovered that the broken drill was gone after about 10 minutes, but it may have dissolved long before that).
Also, the tiny amount of acid you need means you could probably dribble it into a horizontal hole (in, say, a motorcycle engine case). As long as you flush the area with plenty of water afterwards, it should work fine.
So I recommend this method, except for the problem I describe below.
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*When I wrote, "so I bought a quart of 67.2% nitric acid" above, I didn't mention the main downside. You're not gonna find concentrated acid at Home Depot and similar places, and nitric acid is harder to get than most.? I've bought hydrochloric (muriatic) acid without difficulty (this IS at Home Depot and Lowes). I also once bought a quart of 98% sulfuric acid at an industrial chemical supply house. It came in a heavy-duty polyethylene bottle shipped normally in a sturdy cardboard box.
But 10 or 15 years ago when I ordered the quart of nitric acid from that same supply house, the shipping was $30, which was a lot back then. (This is one reason I bought a whole quart. I only needed a little, but the shipping dwarfed the cost of the acid, so I ordered the big bottle to eliminate the chance I'd ever have to pay that shipping again).
But what I got for my $30 was impressive, and I don't think you could get it for anywhere near that price nowadays: FedEx called me on the delivery day to ensure that I was home. Then it sent a truck and driver directly to my house in Staten Island from their distribution center in New Jersey, and the truck carried the driver, the nitric acid and nothing else. (And when I signed for it, the guy gave it to me as if he were handing me a live grenade).
The acid was also VERY, VERY carefully packed.? My sulfuric acid had been shipped in a heavy-duty polyethylene bottle packed in a cardboard box.? By contrast, the nitric came in a brown glass bottle, plastic-wrapped, then surrounded by plastic netting. This, in turn, was encased in form-fitted Styrofoam inside a wooden crate, the outside of which was plastered with dire warnings about letting it tip over or bump against anything.?
All this seemed excessive to me then. I majored in chemistry in college and I'm used to handling acids. But I later read that shipping companies have had serious problems with nitric acid in the past when bottles tipped over, clunked together or broke, resulting in disasters and even deaths.?
So the extreme caution FedEx used in my shipment may have been as much to keep slapdash employees alert as to warn me. But I can't imagine what this kind of shipping would cost nowadays, or how long it would take. So unless you live within driving distance of a chemical supplier or you have some other way to get it, obtaining nitric acid to dissolve taps and drills may be financially impractical.
By contrast, USING nitric acid tto dissolve taps and drills?isn't a big deal, if you're familiar with handling acids. Getting any strong acid your eyes would be catastrophic and nitric produces nasty fumes. But if you have proper eye protection and ventilation, spilling a little on your hand, etc., is no problem if you PROMPTLY wash it off, and you only use enough to fill the hole where the broken tap or drill is.
So in short I'd say concentrated nitric acid is an excellent way to remove broken taps and drills -- if you can find some. There's a 17th century recipe for hare soup that allegedly began, "first catch your hare."? The same thing is true here. If you want to remove broken taps and drills with nitric acid, first get your acid. After that, it's easy.
Mike Taglieri?
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I have to move taps and bolts from casting.
I EDM very easy to do.?
I heard of using?nitric acid in pass but no information on using.
Dave?
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I did not major in chemistry and only took the basic class that all science and engineering students take. ? ?So my understanding is that nitric acid would react with the aluminum. ? But you say that with enough concentration it does not?
Why is this? ? I’m trying to work it out and can’t. ?I’m guessing it has to do with the lack of water.
BTW, did they really used to sell chemicals in Imperial units?
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On Mar 12, 2024, at 8:52?PM, Miket_NYC <mctaglieri@...> wrote:
Has anyone else here used concentrated nitric acid to remove broken taps or drills from aluminum? I tried it for the first time on Friday and it works great.?
The theory behind this is complicated, but basically, CONCENTRATED nitric acid attacks steel but does not attack aluminum. (DILUTE nitric attacks both).?
I was intrigued by this idea when I first learned about it many years ago, so I bought a quart of 67.2% nitric acid.*? But I never needed it until Friday because I'm very careful using taps and drills.?
But on Friday I broke off a #25 drill in one of the final steps of making a special tool holder for my minilathe. (It's designed to hold a single-edged razor blade dead vertical in the tool post). This was originally a piece of aluminum scrap, but I'd already done several operations on it with my shaper and mini-mill, so ruining it at that point would've been a real bummer. This seemed like a time to try the acid.??
So I washed off the part with Dawn dishwashing liquid,? rinsed it well, and blew the hole dry with compressed air. I figured the acid shouldn't have to fight its way through oil to get to the metal and it also shouldn't get diluted because dilute nitric acid attacks aluminum as well as steel. (Both of these precautions may have been needless, but this was my first time so I was being careful).?
Then I used a plastic soda straw to dribble a few drops of the concentrated acid into the hole. Nothing seemed to happen for several minutes and I was getting impatient. So after 10 minutes or so, I used a sliver of the same plastic straw to poke around in the hole and feel if the broken drill was loose yet.??
No, the drill wasn't loose -- it was gone, transformed into black sludge.? I rinsed the part off in cold water and the hole was perfect. I was ready to start drilling again.
There are, of course, other ways to remove steel taps and drills from aluminum, but they all take hours or days. Concentrated nitric acid is fast! (And I don't even know HOW fast. I discovered that the broken drill was gone after about 10 minutes, but it may have dissolved long before that).
Also, the tiny amount of acid you need means you could probably dribble it into a horizontal hole (in, say, a motorcycle engine case). As long as you flush the area with plenty of water afterwards, it should work fine.
So I recommend this method, except for the problem I describe below.
‐---------------------------
*When I wrote, "so I bought a quart of 67.2% nitric acid" above, I didn't mention the main downside. You're not gonna find concentrated acid at Home Depot and similar places, and nitric acid is harder to get than most.? I've bought hydrochloric (muriatic) acid without difficulty (this IS at Home Depot and Lowes). I also once bought a quart of 98% sulfuric acid at an industrial chemical supply house. It came in a heavy-duty polyethylene bottle shipped normally in a sturdy cardboard box.
But 10 or 15 years ago when I ordered the quart of nitric acid from that same supply house, the shipping was $30, which was a lot back then. (This is one reason I bought a whole quart. I only needed a little, but the shipping dwarfed the cost of the acid, so I ordered the big bottle to eliminate the chance I'd ever have to pay that shipping again).
But what I got for my $30 was impressive, and I don't think you could get it for anywhere near that price nowadays: FedEx called me on the delivery day to ensure that I was home. Then it sent a truck and driver directly to my house in Staten Island from their distribution center in New Jersey, and the truck carried the driver, the nitric acid and nothing else. (And when I signed for it, the guy gave it to me as if he were handing me a live grenade).
The acid was also VERY, VERY carefully packed.? My sulfuric acid had been shipped in a heavy-duty polyethylene bottle packed in a cardboard box.? By contrast, the nitric came in a brown glass bottle, plastic-wrapped, then surrounded by plastic netting. This, in turn, was encased in form-fitted Styrofoam inside a wooden crate, the outside of which was plastered with dire warnings about letting it tip over or bump against anything.?
All this seemed excessive to me then. I majored in chemistry in college and I'm used to handling acids. But I later read that shipping companies have had serious problems with nitric acid in the past when bottles tipped over, clunked together or broke, resulting in disasters and even deaths.?
So the extreme caution FedEx used in my shipment may have been as much to keep slapdash employees alert as to warn me. But I can't imagine what this kind of shipping would cost nowadays, or how long it would take. So unless you live within driving distance of a chemical supplier or you have some other way to get it, obtaining nitric acid to dissolve taps and drills may be financially impractical.
By contrast, USING nitric acid tto dissolve taps and drills?isn't a big deal, if you're familiar with handling acids. Getting any strong acid your eyes would be catastrophic and nitric produces nasty fumes. But if you have proper eye protection and ventilation, spilling a little on your hand, etc., is no problem if you PROMPTLY wash it off, and you only use enough to fill the hole where the broken tap or drill is.
So in short I'd say concentrated nitric acid is an excellent way to remove broken taps and drills -- if you can find some. There's a 17th century recipe for hare soup that allegedly began, "first catch your hare."? The same thing is true here. If you want to remove broken taps and drills with nitric acid, first get your acid. After that, it's easy.
Mike Taglieri?
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I found removing large taps and large bolts from casting and steel plate is easier than smaller sizes.?
EDM makes under 3/8" easy to do.?
Dave?
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Chris Albertson
9:48pm? ?
I did not major in chemistry and only took the basic class that all science and engineering students take
I ways say away from?nitric acid. Just not need on self too. Dave?
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This is great news! Looks like I was wrong about the difficulty of buying nitric acid nowadays? -- Walmart, with free shipping!? Maybe the hysteria I found in the commercial shipping companies was only temporary.
So get some nitric acid, if you ever drill ot tap aluminum! But remember, be careful. And personally, I prefer to deal with dangerous substances in small quantities, so I got this 60mm glass-stoppered bottle for my future nitric acid use, and I'm keeping the big bottle in a safe place (HDPE for bottles is also safe).? Always wear eye protection, keep out of reach of kids, etc.??
Some people here have said they'd rather use EDM. Your choice, but last I looked, an electricial discharge machine cost quite a bit more than $29.95.
Finally, I've found that doing anything that requires great care -- from working with acids to making coffee in a French press -- is safe enough if you give it your total attention. Multitasking is always a bad idea when one of those tasks could kill you.
Mike Taglieri?
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As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you.?
And that also goes for splashes on your lab coat/apron/etc.
Also typical latex or nitrile gloves do not protect very well against con Nitric.
On Mar 12, 2024, at 10:40 PM, Miket_NYC <mctaglieri@...> wrote:
So get some nitric acid, if you ever drill ot tap aluminum! But remember, be careful. And personally, I prefer to deal with dangerous substances in small quantities, so I got this 60mm glass-stoppered bottle for my future nitric acid use, and I'm keeping the big bottle in a safe place (HDPE for bottles is also safe).? Always wear eye protection, keep out of reach of kids, etc.??
Some people here have said they'd rather use EDM. Your choice, but last I looked, an electricial discharge machine cost quite a bit more than $29.95.
Finally, I've found that doing anything that requires great care -- from working with acids to making coffee in a French press -- is safe enough if you give it your total attention. Multitasking is always a bad idea when one of those tasks could kill you.
--?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism.
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Well put
It some in welding you watch for .
Why you can NOT use nitrogen for shielding.
It could form in lungs Nitric acid?
That is ok in third world countries but not in America.?
Dave?
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Bruce J
11:17am? ?
As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you.?
And that also goes for splashes on your lab coat/apron/etc
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The question was just technical. ?I’ve never needed to remove a tap. ? I would never use this method.
But still, I wonder why the 66% concentration works where the more dilute does not. ? I’m guessing it is the water
Maybe the chem major can explain.
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On Mar 12, 2024, at 10:07?PM, davesmith1800 <davesmith1@...> wrote:
Chris Albertson
9:48pm? ?
I did not major in chemistry and only took the basic class that all science and engineering students take
I ways say away from?nitric acid. Just not need on self too. Dave?
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Well I didn’t know the answer off the top of my head but Google does:
" Although aluminium reacts with?dilute?nitric acid to produce aluminium nitrate and hydrogen gas, concentrated (>60%) nitric acid is such a powerful oxidising agent that it instantly causes a thin layer of aluminium oxide to coat the surface of the aluminium.The oxide coating is resistant to nitric acid attack and therefore prevents any further reaction. This process is called??and also occurs with chromium, cobalt, iron and nickel."
Note, this is exactly the same process in Aluminum when it contacts oxygen, and why Aluminum doesn’t corrode in general; it pretty much instantly forms a durable aluminum oxide layer on the surface. (Also why you need to use shield gas while welding it)?
Some more info on passivation in general. Iron is passivated by con Nitric, but steel is not.
On Mar 13, 2024, at 12:06 PM, Chris Albertson <albertson.chris@...> wrote:
The question was just technical. ?I’ve never needed to remove a tap. ? I would never use this method.
But still, I wonder why the 66% concentration works where the more dilute does not. ? I’m guessing it is the water
Maybe the chem major can explain.
On Mar 12, 2024, at 10:07?PM, davesmith1800 <davesmith1@...> wrote:
Chris Albertson
9:48pm? ?
I did not major in chemistry and only took the basic class that all science and engineering students take
I ways say away from?nitric acid. Just not need on self too. Dave?
--?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism.
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What percentage of nitric acid is required? I broke a?M3x0.5 tap on my mini lathe doing a bed extension and could not get it out due to it breaking below the casting. I tried everything. I have time to wait as I actually just got home from the hospital with another back surgery and have quite a few months of doing nothing ahead of me.
Thanks, Ron
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No, the specific method I was talking about is for getting broken steel taps and drills out of ALUMINUM, not cast iron, like the bed of a minilathe.? But maybe you could use acid anyway, which would eat away at the tap AND the lathe bed.? Then, after the tap's loose enough to remove, you could plug the hole and redrill it.? I've corrected misdrilled holes (sometimes done by the factory!) by drilling and tapping a larger hole, then screwing in a bolt with permanent threadlocker or epoxy.? Then saw it off flush with the surface and you have fresh metal to drill and tap where you want it.
At any rate, explain in detail where on the bed it happened (with pictures if possible)?and someone here can help you.??
Mike Taglieri
On Wed, Mar 13, 2024 at 6:38?PM Ron Y < ryulick@...> wrote: What percentage of nitric acid is required? I broke a?M3x0.5 tap on my mini lathe doing a bed extension and could not get it out due to it breaking below the casting. I tried everything. I have time to wait as I actually just got home from the hospital with another back surgery and have quite a few months of doing nothing ahead of me.
Thanks, Ron
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"As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you."
I understand your concerns, but what I said in my original post was: "spilling a little on your hand, etc., is no problem if you PROMPTLY wash it off." How much more emphasis do?you think I should?add beyond that?? If you're paying attention, you'd?wash it off immediately.
That's what I always do now, but decades ago, I spilled some?concentrated nitric on my hand in a college chemistry lab, and it was just as you say. I felt no pain and didn't notice anything for?30 seconds or so, until I saw smoke rising from my hand. I DEFINITELY wasn't paying enough attention then, and I wound up with what looked like bad?sunburn on my hand. But it went away in a week or two?and there was no permanent harm.??
I assume?anyone who uses this for dissolving broken drills and taps will use appropriate precautions. But you must know more about lab procedure than I do, so if you have more to add besides eye protection, paying attention, and having?running water handy, please tell us what it is.
Mike Taglieri?
As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you.?
And that also goes for splashes on your lab coat/apron/etc.
Also typical latex or nitrile gloves do not protect very well against con Nitric.
So get some nitric acid, if you ever drill ot tap aluminum! But remember, be careful. And personally, I prefer to deal with dangerous substances in small quantities, so I got this 60mm glass-stoppered bottle for my future nitric acid use, and I'm keeping the big bottle in a safe place (HDPE for bottles is also safe).? Always wear eye protection, keep out of reach of kids, etc.??
Some people here have said they'd rather use EDM. Your choice, but last I looked, an electricial discharge machine cost quite a bit more than $29.95.
Finally, I've found that doing anything that requires great care -- from working with acids to making coffee in a French press -- is safe enough if you give it your total attention. Multitasking is always a bad idea when one of those tasks could kill you.
--?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism.
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Mike, I bet your skin around the wound had some yellow stains.? When nitric acid reacts with soluble proteins it produces xanthoproteic acid, which is yellow in color.? ?I took my chemistry labs in the 1960s before safety became a big issue, but I knew enough to be very, very careful and used PPEs, the fume hoods, etc, but when I developed some yellow stains on my hands my professor spotted them and gave me some extra reading material.? ? And Bruce, thanks for the information on passivation.? I’ve seen the word associated with metals for years, but was always too lazy before now to look it up.? ? For everyone else, don’t forget that tomorrow is p day!? Yum. ? Jerry F. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Miket_NYC
Sent: Wednesday, March 13, 2024 5:29 PM
To: [email protected]
Subject: Re: [7x12MiniLathe] Using nitric acid to remove broken taps or drills from aluminum? "As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you." I understand your concerns, but what I said in my original post was: "spilling a little on your hand, etc., is no problem if you PROMPTLY wash it off." How much more emphasis do?you think I should?add beyond that?? If you're paying attention, you'd?wash it off immediately. That's what I always do now, but decades ago, I spilled some?concentrated nitric on my hand in a college chemistry lab, and it was just as you say. I felt no pain and didn't notice anything for?30 seconds or so, until I saw smoke rising from my hand. I DEFINITELY wasn't paying enough attention then, and I wound up with what looked like bad?sunburn on my hand. But it went away in a week or two?and there was no permanent harm.?? I assume?anyone who uses this for dissolving broken drills and taps will use appropriate precautions. But you must know more about lab procedure than I do, so if you have more to add besides eye protection, paying attention, and having?running water handy, please tell us what it is. ? As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill it on you because it promptly kills the nerves in your skin so you don’t notice it dissolving you.? And that also goes for splashes on your lab coat/apron/etc. Also typical latex or nitrile gloves do not protect very well against con Nitric.
? So get some nitric acid, if you ever drill ot tap aluminum! But remember, be careful And personally, I prefer to deal with dangerous substances in small quantities, so I got this 60mm glass-stoppered bottle for my future nitric acid use, and I'm keeping the big bottle in a safe place (HDPE for bottles is also safe).? Always wear eye protection, keep out of reach of kids, etc.?? Some people here have said they'd rather use EDM. Your choice, but last I looked, an electricial discharge machine cost quite a bit more than $29.95. Finally, I've found that doing anything that requires great care -- from working with acids to making coffee in a French press -- is safe enough if you give it your total attention. Multitasking is always a bad idea when one of those tasks could kill you ? ? --?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism. ?
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Like Miket_NYC said?It is very dangerous to use.
If see cooking shower what them use liquid nitrogen it too in dangerous. Nitric acid is more dangerous.?
Use a EDM machine if do not have got to your locale Automovie Machine Shop and they cheaper that time spent in the Hospital ? and the bill.?
There is a lot out there you buy it is not safe. Besides that the FEDs look to see what you doing.?
Dave?
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Miket_NYC
5:29pm? ?
"As a trained chemist I’ve needed to use con Nitric a bunch of times. You do have to be careful not to spill
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" Re: Using nitric acid to remove broken taps or drills from aluminumFrom:?davesmith1800Date: Thu, 14 Mar 2024 02:06:35 EDTLike Miket_NYC said?It is very dangerous to use.
If see cooking shower what them use liquid nitrogen it too in dangerous. Nitric acid is more dangerous.?
Use a EDM machine if do not have got to your locale Automovie Machine Shop and they cheaper that time spent in the Hospital???and the bill.?
There is a lot out there you buy it is not safe. Besides that the FEDs look to see what you doing.?
Dave "
From what I can see the EDM machines are not affordable for the average hobbyist unless I am missing something.
Ron
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You have Automovie Machine Shop do the work. Most today are for machining but ato shops use the lower cost ones.
You can build one for a microwave transformer.? Very low cost just for taps.?
I started one but did break taps so unfinished.?
Dave?
Dave?
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I rarely use EDM, despite having a small commercial machine! It always takes longer to set up than it seems like it should + it makes a mess. There's always a lot of dielectric fluid that gets splashed out during the process, no matter how deep the enclosure is.
I get good results with small carbide rotary files to remove the central portion of the broken tool, along with shaking the debris out fairly often. Particularly for small stuff, carbide dental bits in a dental handpiece work well. I wouldn't want my dentist to use them on me, but, there are a lot of inexpensive, Indian dental bits available.
Roy
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You can mix your own dielectric fluid .
All the ingredients are found home.?
Some where have mix for low cost dielectric fluid?
Dave?
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davesmith1800
