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I enjoy working with metals, but have sadly neglected the annealing process. I solder brass and copper and am doing rivets for the harder metals. I'm not a pro or anything like that. Anyway, some questions:

1. Does annealing work for all metals incl steel and alum?

2. For a large sheet, I assume a large propane torch best; what color should the metal be and for how many seconds?


3. Would there ever be a need to re-anneal a piece of work and does this degrade the metal (repeated annealings)


4. Is there a way to reharden metals after annealing. For instance, I used a prize lineman's pliers to hold hot pieces of metal, not realizing I may have annealed the pliers.


Thanks!
 

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Hi
Steel you can bend hot or cold . If the bend cracks when you do it then heat it too cherry red or you should be able to buy usabend steel for strip sections !
Copper you heat to dull red , quench in water , then bend and if it starts to resist the bending then heat up again . To harden tap with a hammer or time and use will harden it .

Brass needs to be a certain grade for bending but can be heated a certain amount to soften , use soap see Aluminium!
Aluminium is a difficult beast so beware . Rub soap on the area and heat up till the soap goes brown and let cool then bend . Do not over bend and repeat the anealing if you feel increased resistance during bending .If you over heat the aluminium it melts into a blob so go steady

So you see you buy metals for a specific job as there numerous different grades made all to suit different applications . If you just pick up unknown grades try them but dont be dissapointed if they dont do the required job
Brent
 

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Posted By SE18 on 03/02/2009 8:34 AM
I enjoy working with metals, but have sadly neglected the annealing process. I solder brass and copper and am doing rivets for the harder metals. I'm not a pro or anything like that. Anyway, some questions:

1. Does annealing work for all metals incl steel and alum?

2. For a large sheet, I assume a large propane torch best; what color should the metal be and for how many seconds?


3. Would there ever be a need to re-anneal a piece of work and does this degrade the metal (repeated annealings)


4. Is there a way to reharden metals after annealing. For instance, I used a prize lineman's pliers to hold hot pieces of metal, not realizing I may have annealed the pliers.


Thanks!









I'll give this my best shot:

1) Annealing, technically will work for all common metals. I know nothing of the exotics. Annealing aluminum is a whole different proposition from steel (ferrous metals) and copper/brass (copper-based metals, both of which are opposite the other.)

2)for steel: heat to dull red--depending upon type of steel, not all steels have the same metallurgy, just like pies don't all have the same ingredients. For commonplace steel, as before, then either bury it in sand (that has also been heated) and let the whole works cool out for a day. Most of the time, with most of the steel we have to hand, you can heat it dull red hot and just set it aside and let it air cool. I posted on telling the various steels a couple of days ago, you need to search it out.

Also note, you'll find as many different opinions as people, you'll have to sort through and find out which know what they're talking about by having done it, and which are passing along hearsay. I fall into the former category.

3) In general terms, forget about annealing aluminum. To do it right, you need a big furnace and a big freezer, and then you only have an open time of a few hours. This from my son, a casting inspector. I would never bother trying.

4) Brass/copper tends to harden as you work it. Periodically, you have to reheat and let cool.

5) Steel needs to be annealed before you start, and you're good to go to the end of your work. Then you must reharden it. There are various means and thousands of favorite 'pickling solutions' among hobby blacksmiths. I use motor oil or water, depending on the size of the part. You need VOLUME of fluid to remove BTU's of heat from a workpiece, remember. These dippy little cups under grinders are for cooling small drill bits, and that's bout it.

6) If you are making a cutting tool, you must reharden after forming and rough grinding. I generally content myself with heating red hot and quenching in cold water. For the steel I have to hand and the purposes I put the tool to, it's enough.

ALL my suggestions are based on a non-production run. One-offs or light duty use.

7) If you try to anneal a large sheet of steel, it will almost certainly warp and wrinkle. So keep your workpiece small enough to planish if you want it flat. What you want for large pieces is an oxy/acetylene rig with a special tip called a 'rosebud' Once you light one off, you'll understand the name. They spread heat out, rather than concentrating it like a tip does.

8) Read about any book on hobby blacksmithing to get examples. The Web should give you lots of info.

9) Repeated annealing can degrade the metallurgy of a piece. 'Purists' (anyone who has heated a piece of metal successfully) claim carbon induced by the torch hardens metal. Forget it, for hobby purposes. So can repeated reworking of the piece via hammer and whatnot. It's a crapshoot, to decide which caused your almost-finished piece to give up ( crack/break) but generally, over-working causes more harm than repeated annealings. Now, this leaves out the 'idiot factor' where someone has no clue and practically melts the material being worked. Experience and observation and trial and repeated trial are your best guides. They've worked well for me over the years.

I don't know what kind of metalwork you do, it'd help if you were specific. Don't overlook the value of a small 'pot forge' and an anvil. I have a forge made from an 18 wheeler truck drum, and a piece of RR track. I fire with wood. I have had 'experts' dismiss me: "You can't weld steel with a wood fire." Even when I show them the results, they sneer. So much for preconceived opinions. You can, but anyone idiotic enough, or dedicated enough, to want to forge weld when there's arc, gas, and whatnot is a dillitante, in my NSHO. I do metalworking to make things I want/need, not to genuflect to the god of True Path smithing.

Of course you can (and must, usually) reharden a piece of ferrous (steel) tooling or part that will see force, which causes wear. You do that as described above. Annealing, then 'drawing the temper' are issues you best need to get a book to learn about. Again, a blacksmithing book will do well enough. There is no dark art to it, just sweaty trial and error, then all of a sudden, it 'clicks', and you're there, the possessor of a new (and getting rare) skill.

Hope this helps.

Les
 

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Non ferrous; heat and let cool. ...dull cherry red Work slow for an even heat. To temper same steps but quench in cold water
Steel/iron heat and quench. A layer of oil on top of water. The oil keeps water out of the metal's pores
 

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Les --

Does that work for stainless as well? I have some stainless steel pieces that have to be bent into a U-shape. I didn't quite get it right the first time. I've reworked it several times, and the sides are now parallel, but the "bottom" isn't square to the sides. I'm afraid to touch it any more. The problem is that I don't have any spare parts, so there isn't any Plan B if I mess up.
 

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Astra,

Does what work for bending Stainless? I need a more detailed idea of what you're doing.

Stainless steel is a mongrel grade in my utterly biased opinion. There are many diffferent grades of stainless. So the question I think you are asking is, 'will re-heat damage my part?'

Ans: I don't THINK so. I'd have to see the part. In general, most steels are fairly forgiving. (Which means that some few are not). Which sounds like I'm playing CYA. (I am).

Shoot me a pic via email or this boad, and some description what you're doing and where you want to go.

I can be certain of one fact: bending cold stainless will give you grief.

I liberated some stainless and spent half a day making a pair of gaffs for my pontoon boat, happy and secure in the knowledge that I would have glorious-looking, rust free items to the envy of fellow boaters. Those sob's rusted like a cheap tin can practically from one week to the next. Just a heavy, ugly, contaminated-looking rust color, they were structurally sound and went with the boat. Grr.

Les
 

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Discussion Starter · #7 ·
thanks; so quenching in water hardens metals and heating anneals. I guess that's why tools are called "drop forged;" b/c heated and dropped in water.

Q: what happens if water gets into metal's pores? Didn't know this.
 

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Quenching in water or oil hardens ferous (iron) metals, but with copper it doesn't matter whether it is quenched in anything at all or if it is left to ccool or even cooled very slowly using controlled heaters, it just doesn't harden that way. Heat it and it is annealed (softened) no mater how it is cooled. It hardens when bent or beaten. I don't know about aluminium, zink, tin or any other metals.
 

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Posted By SE18 on 03/03/2009 6:22 AM
thanks; so quenching in water hardens metals and heating anneals. I guess that's why tools are called "drop forged;" b/c heated and dropped in water.

Q: what happens if water gets into metal's pores? Didn't know this.









Uh ... no. 'Drop forged' means this huge die falls on an anvil holding very hot metal. It can either cut the wrenches, say, free from the sheet/bar stock, or by means of a mating pattern block underneath, meet partway to cut the tool out. (This is a simplification). Then they grind the place where the two dies met. Final grinding to size comes next. That's why, on a cheap wrench, you'll see grind marks along the outside edges. (The dies are a tad more complicated, but you get the idea. Like cutting cookies out. Better quality wrenches use better metallurgy and are finished nicer and to a closer tolerance.) Quenching on an industrial production level gets a bit more involved than us'ns who do it in our backyards.

A: Essentially, nothing. Some feels it causes rust in the pores of the metal. I happen to not worry about it, because everything gets to meet a wire wheel after forging, and a coat of oil after final finish. People have fun arguing the pros and cons of this. Do it either way you find works best for you. Water is felt to 'quench' --remove the heat--faster, and FWIW, I think it tends to; oil cools a tad more slowly--sometimes a good thing--but for practical purposes, either is just fine.

Les
 

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Low carbon steel is generally better for forming and welding. More carbon content increases difficulty. On the other hand, low carbon steel is more difficult to harden if you need to. If you ever need to harden low carbon steel after working it, us a product called "Kasenit". Heat the part to red and sprinkle on the Kasenit powder and re-heat. Plunge in cold water. Kasenit puts a hard shell in the steel while the center remains mild.

I don't quench hot copper in water to annel. Just let it cool in room temp.

Bob
 

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Sorry to say there are no blanket statements allowed! lol

Non ferrous metal react differently than ferrous. My knowledge comes from 26 years making jewelry; sliver and gold. NF's get hard from working them, ie; bending and hammering. Annealing prevents cracks and porosity from developing as the molecules pull apart... the outer edge of a bend stretches as the inner compresses.

In 1986 my boss paid $250 for this info when he had a Jeweler give me a 'Journeyman jewelry course. Amazing I still have the notes from that day in my hand now! Jewelers work with high quality steel in our engravers. They must be kept sharp to do their job and tempered to hold an edge. The process requires anealing and tempering, plus cleaning the surface of the metal.

I know this is a job specfic method, not fabrication, but it will help many to understand the processes they can adapt. I was using an Oxy/Acetylene torch.

Subject; To Temper Engraver Steel (after sharpening tip)

1. Polish out any grinding lines on sides - They weaken graver.
2. Wipe thin solution of ivoy soap on the metel.
3. Heat cherry red and dunk swish in ice water with a film of oil on top.
4. Test with a file, should be glass hard, if not repeat 2 'n 3

Stop and polish and apply soap again, helps to see color change in metal.

5. Apply gentle heat one inch from tip... when lightest straw color hits the point dunk and swish in ice water + oil

Test on a piece of soft iron for hardness. If too hard it will chip, repeat #5, too soft repeat all.

you can send your checks to; me

Water inside metal can cause all sorts of problems when you reheat it; too hot a flame and you might seal moisture inside until it pops out and as another has posted not all stainless is the same. As we have seen not all importers follow our regulations as strictly as we did... My stainless steel track comes in 2 shades of color...same brand.

John
 
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as my ranch was remote from the next city, i sometime forged some bits for my agricultural tools.
confronted with the problem to harden pieces, an old horsesmith told me to have a barrel with blood from slaughtering and pee.
dipping redhot pieces of steel in the barrel hardens them.
i tried it. it stinks and it works.
i ignore why, but it made my repairparts harder.
 

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Aluminum sheets aren't difficult to anneal. I do it all the time with aluminum cans to make them soft enough to run through a paper crimper to make "corrugated tin." I just put two or three cans in my gas bbq and heat them up. After about half an hour I turn off the gas and let them cool slowly.

When they're cool to the touch, I cut the ends off with a band saw, slice them open and lay them flat.
 

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Discussion Starter · #18 ·
I tried annealing aluminum cans and they turned into crispy fries. Tried it last night with a penny and it fried as well. I might need to use a smaller torch!
 

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SE,

You need to follow Dick Friedman's process, above. It's too easy to concentrated heat with a torch, especially with a very thin aluminum can.

Les
 

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SE

What the previous individuals have been telling you is good information.

First off, depending on the mint date on the penny you tested, if the date was 1982 or earlier then it's 95% copper, if on the other hand the date was 1983 to present day then it's 97.5% zinc and copper plated. Like Les has said you've got to know the metal you're working with.

As for using a torch on the aluminum cans, too much concentrated heat on very thin metal, most likely melted. That's why the BBQ, dispersed lower temp heat applied for a longer time.
 
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