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View Full Version : Does Soft Rolled Copper get harder over time



chefwong
08-09-2012, 09:16 AM
I can't recall where I read this , and it stuck with me.

Does rolled/soft copper get harder over time.
So let's say for example, I have leftover 1/2" I used on a project X years ago, and plan to use some now. Is it just as *soft* - bendable as it was when it was ~freash~ or does it actually become less malleable over time.

Terry
08-09-2012, 09:22 AM
Anytime soft copper is bent, it gets stiffer.
If the coil is left alone, it should remain soft. If it's been moved around a lot, there is a possibility of it becoming more stiff. However, most of us plumbers carry soft copper in the vans and we manage to work with it. Copper sitting in a corner should be just fine.

chefwong
08-09-2012, 09:25 AM
Interesting .....
So if I take a 18" cutoff , bend a 90 on it , that 90 becomes stiffer.
I guess it's a molecular thing...

Thanks TL

Terry
08-09-2012, 09:46 AM
The more times it's bent, the stiffer it gets. It also gets warmer as it bends.

BillTheEngineer
08-09-2012, 02:24 PM
In metals it's know as work hardening. Yes it gets hard but it also get more brittle (ie easier to crack). It can be brought back to being soft through an annealing process, but that is something that could only be done with a specific understanding of the metallurgical properties of copper.

nestork
08-09-2012, 04:38 PM
Bill's right. The hardening results from bending the copper, not because of it's age. Iron (or steel) and I expect all metals are the same way in that regard.

Boston1
08-09-2012, 09:19 PM
One of the things I do is metal art. I am also a cert. welder. Lately, I make copper leaves from 16 Oz. flashing ,stems from 10 ga. copper ground wire. I keep heating the leaves red with My B tank setup. Bend and pound. I also heat alum. to anneal.
the term is work hardening metal,when You pound or bend it. Hope this helps someone.

bluebinky
08-10-2012, 09:55 AM
Bill's right. The hardening results from bending the copper, not because of it's age. Iron (or steel) and I expect all metals are the same way in that regard.
Not an expert, but some metals work harden easier than others. I had drilled a lot of mild steel before the first time I tried to drill stainless. Boy what a surprise!

nestork
08-10-2012, 09:31 PM
Not an expert, but some metals work harden easier than others. I had drilled a lot of mild steel before the first time I tried to drill stainless. Boy what a surprise!

No, stainless steel is INHERENTLY harder than mild steel. It didn't harden up because you tried to drill into it, it was harder to begin with. 304 stainless steel is about twice as hard as mild steel.

If you're going to be drilling into stainless steel, then you're best off buying titanium nitride coated drill bits (the gold coloured ones) and just throwing them away as they dull.

Cobalt bits are harder than High Speed Steel bits, but the titanium nitride coating on titanium bits is the hardest dam thing out there. So, while you may have to spend an extra $10 for three or four titanium bits, you'll save $10 worth of time drilling.

For general all-purpose use, cobalt bits are the best bits to have in your tool box cuz you can sharpen them when they dull and effectively have a new cobalt drill bit. Sharpening a titanium bit grinds off the super hard titanium nitride coated cutting edges on the front of the bit, leaving you with what is effectively an ordinary high speed steel drill bit. So, while you can sharpen cobalt bits for better economy, if the job involves drilling into a hard material like stainless steel, I'd buy some titanium bits and get the job done faster cuz time is valuable too.

Here, read this:
http://www.irwin.com/support-services/ask-irwin/4

PS:: Terry Love:
Could you replace the "Mechanical Engineer" under my UserID with the phrase "Janitorial Technician" if it fits, or "Janitorial Tech." I haven't worked as a professional engineer in over 25 years. Now, I own a small apartment block and MOST of what I do is clean up after people when they vacate their apartments or spill laundry soap all over my laundry room floors or track mud onto my front lobby carpet. Hence "Janitorial Technician" is a more apt job description of what I actually do during normal business hours than Mechanical Engineer. (I also repair, renovate and manage the building, but MOST of my time is spent cleaning up after people.)

Hackneyplumbing
08-12-2012, 04:19 AM
I had some type l soft coppa left in a garage for a few years and it expanded and contracted so much from the natural temp changes it became more difficult to work with.

chefwong
08-12-2012, 07:19 AM
For those familiar with annealing copper, is it plausible that if a rolled got slightly stiffer...and without a A torch onhand, could one just bake at high temps the copper ?

nestork
08-12-2012, 03:04 PM
My understanding is that when copper (or other metals) are annealed, they're heated until they're red hot. I don't think that an oven going through a self clean cycle would get hot enough to anneal your copper.

Your best bet would be to look in your yellow pages phone directory under "Heat Treating" to find companies that harden and anneal metals for other companies. Phone them and find out how much they'd charge to anneal your copper coil.

Boston1
08-12-2012, 05:58 PM
acetylene tank for soldering brings copper cherry red. I have oxy acetylene torches, weed burners, not necessary

BillTheEngineer
08-13-2012, 11:41 AM
Most annealing is not a simple things to do. The likeliness of being able to do it properly with a touch of any type is slim unless it's a small piece of material that you are working with. Plus the amount of time you need to hold the material at the elevated material is important, usually it's not seconds or minutes, it's hours.

http://en.wikipedia.org/wiki/Annealing_(metallurgy)

bluebinky
08-13-2012, 11:50 AM
No, stainless steel is INHERENTLY harder than mild steel. It didn't harden up because you tried to drill into it, it was harder to begin with. 304 stainless steel is about twice as hard as mild steel.

It was a looong time ago. I had decent bits and understood that 304 is harder. I "wrecked" a couple of pieces before realizing what was going on. You do have to pay attention (not let up on the feed) when hand drilling...

ballvalve
08-13-2012, 01:22 PM
Not one of the hundreds of workers in my shop knew how to drill any steel. The secret is PRESSURE enough to get a curl, a flood of soapy water or old tranny fluid [better both mixed together and a bit of diesel, mixed in a hose sprayer]

Most guys just make a fire with their bits and anneal them. I have a 1942 3 ton FOSDICK drill press [won the war] Bought from the school when they decided compukers were more important than an actual skil for 25$. Some of the morons I have hired don't even know how to operate drill chuck. Morse taper? "is that a ring tone?"

This press has coolant, auto down feed with instant release, feed pressure set , manual op, and auto tapping with instant reverse. Its the I-POd of 1942. 10 speed gearbox.

http://www.bid-on-equipment.com/detail~id~129569.htm

nestork
08-13-2012, 09:43 PM
OK, for all the others in here, besides me, that didn't know what a Morse taper was, I did some digging:

The idea behind the Morse taper is that if you have a tapered post and a hole (with the same taper), not only will the two fit together, but with a bit of a tap on the end of the post, the post will wedge itself into the hole tightly enough that the friction between the post and the hole can be used to turn machining bits in drill presses, milling machines, lathes and the like. The Morse taper is only about 3 degrees or so. There are 8 different standard "sizes" of Morse tapers, but they're all about 3 degrees; it's the diameter of the post and hole that change from size #1 (smallest) to size #8 (largest).

http://www.newtotaljoints.info/Morse_taper.jpg

The wedging together of the tapered post into the tapered hole will be so strong that drill bits will break before the friction between the tapers will slip.

To get the tapered post out of the tapered hole, they apparently use a drift to smack the end of the tapered post to jar it loose from the tapered hole.

In the case of a drill press, the chuck can have a tapered post sticking out the tail end of it, and that post fits into a tapered spindle in the drill press. Both the post and the spindle will be machined to have a one of the standard Morse tapers; from #1 to #8.

It's a reliable enough connection that they use it in artificial hips, as shown above.

Or, at least, that's the best I could figure it at 1:00 AM local time.

Hairyhosebib
08-14-2012, 01:01 AM
No, stainless steel is INHERENTLY harder than mild steel. It didn't harden up because you tried to drill into it, it was harder to begin with. 304 stainless steel is about twice as hard as mild steel.

If you're going to be drilling into stainless steel, then you're best off buying titanium nitride coated drill bits (the gold coloured ones) and just throwing them away as they dull.

Cobalt bits are harder than High Speed Steel bits, but the titanium nitride coating on titanium bits is the hardest dam thing out there. So, while you may have to spend an extra $10 for three or four titanium bits, you'll save $10 worth of time drilling.

For general all-purpose use, cobalt bits are the best bits to have in your tool box cuz you can sharpen them when they dull and effectively have a new cobalt drill bit. Sharpening a titanium bit grinds off the super hard titanium nitride coated cutting edges on the front of the bit, leaving you with what is effectively an ordinary high speed steel drill bit. So, while you can sharpen cobalt bits for better economy, if the job involves drilling into a hard material like stainless steel, I'd buy some titanium bits and get the job done faster cuz time is valuable too.

Here, read this:
http://www.irwin.com/support-services/ask-irwin/4

PS:: Terry Love:
Could you replace the "Mechanical Engineer" under my UserID with the phrase "Janitorial Technician" if it fits, or "Janitorial Tech." I haven't worked as a professional engineer in over 25 years. Now, I own a small apartment block and MOST of what I do is clean up after people when they vacate their apartments or spill laundry soap all over my laundry room floors or track mud onto my front lobby carpet. Hence "Janitorial Technician" is a more apt job description of what I actually do during normal business hours than Mechanical Engineer. (I also repair, renovate and manage the building, but MOST of my time is spent cleaning up after people.)

How does Mopologist sound? It was funny when I first started working at ASU. The Custodians had a sign on the door that read "Department of MOPOLOGY" in one of the Engineering buildings. Funny stuff!

nestork
08-14-2012, 09:37 AM
Believe it or not, there is actually quite a bit of science at work in the janitorial business as well. It's learning about that science that helps me do a good job looking after my property.

For example, I'm one of the few mopologists on the planet that can explain to you:

1. why your blue jeans are darker when they're wet. And, I can prove that the explanation is correct with a paper towel and a drop of water to simulate wet and dry denim.

2. why latex paints darken as they dry, and

3. why oven cleaner is so effective at removing soap scum from a bathtub.

Anybody can be a janitor. All you need is an able body, the ability to spik engrish and have an instinctive hatred for teenagers. But, just as in any other kind of work, to stand out from the crowd you not only need experience, but the ability and desire to learn the science and technology behind the subject so that you can correctly interpret unexpected experiences and learn from them. That is, experience alone is great. Book learning alone is great. But when you have both together, you have a knock out punch.

And, contrary to popular belief, there is a lot of science in the field of janitorial work too.

For example, did you know that the dried up urine of all mammals flouresces under ultra violet light? It's true. The flourescence isn't intense like in a 1969 psychadelic poster, but it's bright enough that you can use it to located urine stains, and therefore know WHERE to clean to get the most effective results.

Here's a company selling a UV light made specifically for locating and identifying urine stains:

http://www.baneclene.com/catalog/energizerlight.html

Bane-clene is a well respected name in the janitorial service sector of the economy. Having a light that identifies urine deposits not only helps the mopologist know WHERE to clean, but also helps him to determine how effective the cleaning chemical he's using is by the rate at which the fluorescence diminishes. An experienced and trained eye can even tell what kind of animal left the urine stain, and whether or not that animal was pregnant when it urinated.

EVERY trade, occupation or profession has theory and technology behind it, and knowing BOTH the theory and practical gives the best results in any line of work.

bluebinky
08-14-2012, 11:34 AM
nestork - I was studying for a PhD in Electrical Engineering when my Prof stepped on the janitor lady's dust mop one day. When I asked him about it, he said she wasn't "important". I was forced to leave the University after what I said to that guy ... never regretted that!

ballvalve
08-14-2012, 11:49 AM
Here is where the morse taper does most of its work:

http://www.victornet.com/subdepartments/HS-Taper-Shank-Drills-Inch/1210.html

And oven cleaner is my private secret to make a sanding belt last 5x longer. Just spray and rinse - all gum is gone. for big belts, 40"x75, say, 3 cleanings saves about $175. Buy dry sodium hydroxide and put it in a well marked and hidden hose sprayer. also essential for saw blades.

nestork
08-14-2012, 05:34 PM
nestork - I was studying for a PhD in Electrical Engineering when my Prof stepped on the janitor lady's dust mop one day. When I asked him about it, he said she wasn't "important". I was forced to leave the University after what I said to that guy ... never regretted that!

Kudos to you, Bluebinky.
Someone needed to do that.

ballvalve
08-15-2012, 12:37 PM
should have sprayed him with sodium hydroxide

bluebinky
08-15-2012, 04:44 PM
The prof was a nice guy who went on to become a multi-millionaire CEO of several start-up companies.

He's not a bad guy, but just like so many other people who think that being a doctor/nurse/lawyer/professor/engineer/physicist/technician/whatever makes you somehow smarter and better than everyone else.

If you bother to look deep enough, most fields are respectable and way more involved than they appear.

For example, my dad was a freight train engineer (driver) for 51 years. I'm still trying to figure out some of the stuff he did.