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I watched someone forge an aluminum leaf one time. He checked to see if the aluminum was up to temp by touching it with a pine limb, when he wiped the stick across it and it left a black streak it was at forging temperature.

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If you are going to hot work aluminium remember its hot short and will break up if overheated. Have a look at here for some more details.

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Forge it cold and anneal as needed. Why complicate an otherwise easy thing?

Al as long as it isn't one of the more exotic alloys forges easily and is well behaved. The sound changes quite a bit when it begins to work harden so listen for the change in tone. Still, you'll be amazed at how far you can forge it cold.

Here's an example by Bill Roberts "Ornamentalsmith" a member here. Custom Design Metal Arts by Bill Roberts, Artist Metalsmith. Sculpture Gallery

If you have more questions I urge you to contact Bill. I don't know how often he checks in here but there's contact info on his web site.

Heck, say hi anyway, he's a heck of a nice guy.

Frosty

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good links thank you both. i didn't realise the hot short problem, that is very helpful, and bill roberts has some amasing work

thank you for your help i will probably anneal and work cold

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I have forged alot of aluminium in many different profiles, from horseshoe sizes to 2" square and smaller, and I'm going to tell you that it forges longer than any other metal that I've ever forged. You just cannot overheat it, just like all other metals. It must be forged hot to change the dimension of the metal, but hot for aluminium is only about 800 degrees.

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Thanks for the confirmation, Thats a good general rule, only I find its quite difficult to see red hot on aluminium in or on a forge in anything but darkness, having said that I have only tried that on relatively small sections, usually they forged well enough for what was required without the need for annealing. I will file the information for my future reference and thanks again. I am sure others will also appreciate it.

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If you take Al to red it'll be in a puddle, we used to forge it (5" dia) by taking it into the spring shop which was next to our forge shop and stick it into the spring tempering furnace (which was about 480 to 520 degrees C) let it get hot, drag it out, 3 of us, carrying it at the run, out the front door up the footpath, and into our shop and down to the hammer. It tends to want to stick a lot, in swages, dies, etc. Can't remember how we annealed it.
Cheers
Phil

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Not to mention the suits, office chicky babes,or school kids walking to catch the bus having to jump out of the path of a blacksmith, apprentice and labourer all sweaty and dirty, with a lump of hot metal between them on a carry bar and tongs. Fun stuff.
i seem to recall that one of the prerequeseites for forging Al was it had to be wrought or extruded, not all grades were forgeable.

Phil

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One aluminum forging job I did was a stupid design for mooring cleats on some new aluminum ferry boats. I had to bend pieces of 4" round 90 degrees on a 2" radius. Big pile of 'em. Well fortunately, they just barely fit in my electric heat treat oven. I was able to pile about 25 of then in there, turn the temp to 800F and go home. Next morning I'd bend that pile in about two hours. Not bad at $200.00 each. Course I did have to make some fancy bender tooling, but still............... 100 of them bought a lot of beer! $20.000.00 for a light weeks work, helped make up for all them other jobs......

Added: I'll try not to come across as arrogant or "in your face". I cite prices, yes, to brag, I suppose, but also I want folks to know that there is money to be made, often in the most mundane.

Sad to say I made a lot more on bending jobs like this than on most of that fancy custom forging work. One time I made anchors for new permanent moorings at Pearl Harbor. Take a twenty foot bar of 3" round, bend a "candy cane" in each end and then bend them in a hair pin in the middle. Oh yeah, and then drive over them with the forklift while they were still hot to get 'em flat! We filled a couple containers. They went to Hawaii where they cast them in concrete blocks to sink in the harbor (with just a little of the "hair pin" sticking out).

"office chicky babes"? I can see "politically correct" hasn't invaded Oz yet.

Well my CRS (Can't Remember "Stuff") has progressed to CRAFT (Can't Remember A "Frigging" Thing)

Edited by nakedanvil

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Oh PC is alive and well in OZ, just it doesnt cut the mustard with the blacksmithing fraternity (well not here any way). And dont ever think you are coming across arrogant to me, it's good to know what others charge in other countries for the same sort of jobs that we do here. (on a different tack I had one of my apprentices say, "Why do I need to know how to convert Deg C to Deg F", this post has just shown him. He's a bloke that has done the complete tech course at Sydney TAFE, and has now started his apprenticeship, and we are having to unlearn him some things. You just can't beat experience to teach someone something).

Cheers
Phil

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Grant tell us lots more on prices please. Maybe it will get some of these guys to raise their prices and make us all more money.

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Hi everyone I'm new to the Blacksmith Forum and I am wondering if any one could help me find a way of melting aluminium in some kind of small homemade foundry. I have some books on the subject, but I am looking for a cheep but lasting way of mixing a
castable fire clay for such a small foundry.

Thank's in advance.

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Castable refractory to line your furnace with? McMaster Carr. A homemande version would be something like 25% fireclay, 25% grog(smashed up pieces of flue pipe work well, 45% mason sand, sharp and washed, and 5% iron clad cement. The ready made stuff will likely last longer and not be much more money.

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Anealing aluminum, Here are a few ways, using an acetelyne torch, light just the acetelyne. Coat the aluminum with a layer of carbon, then add oxy and heat till all the carbon burns off. Or rub with a pine stick. When the stick feels greasy it is hot enough. Or use a tempilstick (650F) or use a sharpie (brand of magic marker) or use an infrared thermometer. I use all the methods routinely, depending upon what is at hand. My first choice is always the acetelyne, since the torch is already in your hand anyhow, but I often use propane, so I need some other method to tell the temp. When I use my gasser to heat Al, I use the infrared gun, but must be very carefull.

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Thank you for the castable refractory mix I will give this a try on this project since all the
homemade foundry is for will be a short run to produce some one off castings for a
custom motorcycle.

Thank's again for this help.

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tried the aluminum and forged well cold but much better hot. i had a quarter inch thick plate of al from some cooling unit or something anyway cut a strip off and tried forging it it doesn't move in the core so much as it shrooms out and has ta be corrected alot. didn't red short but i melted a test to see how hot is TOO hot and it didn't glow even melted, which is strange after forging steel.
ps i melted it in my lead ladle, didn't know if it would contaminate my forge or not

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Forge it cold and anneal as needed. Why complicate an otherwise easy thing?

Al as long as it isn't one of the more exotic alloys forges easily and is well behaved. The sound changes quite a bit when it begins to work harden so listen for the change in tone. Still, you'll be amazed at how far you can forge it cold.

Here's an example by Bill Roberts "Ornamentalsmith" a member here. Custom Design Metal Arts by Bill Roberts, Artist Metalsmith. Sculpture Gallery

If you have more questions I urge you to contact Bill. I don't know how often he checks in here but there's contact info on his web site.

Heck, say hi anyway, he's a heck of a nice guy.

Frosty


LOL.....checks in the mail, Frostilio. :o:D;)
I don't check in here enough.........glad I did today. I do have a lil info that might be helpful to this thread. Let me start by saying I've been forging aluminum since '89. And I TOO was taught that you "had to forge it hot". I've found out through a LOT of experimentation......that "generalization" is false. Like Jer said......you'd be surprised how far you can push the material cold. Of course there are exceptions to every rule......SOME alloys will NOT let you forge them cold(one example 7000 series will work harden and split). I normally use 6000 series(6061, 6063)but have also used 5000, 3000 and a few others.

I haven't finished reading this thread.......but noticed that someone has already said that you WON'T see any RED when annealing aluminum.... until it's to late.
Maybe I should read the rest of this thread before I add anymore.

I'll be baaaaaaaack.....oh........and I want to thank Youngsmith for the kind words. Edited by ornametalsmith

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