6 replies to this topic

[Christopher Rice]

Where can one get some info on forging aluminum?  Have any of you tried it?  I think Bill R. has, just wondering how tricky it is, and how hot, what type of forge etc.  More curious right now than actually giving it a go, I should have used it for a project I just finished, but it was an after thought.  
                 -chris

[AvishaiW]

I tried it many years ago and it is a bit tricky. The workable temperature window for aluminum is much narrower than for steel. This is because exposed aluminum surface is immediately covered by a thin layer of aluminum oxide. This thin oxide layer softens at a higher temperature than the base metal. As a result there is a risk that the outer oxide layer is soft enough for forging, but under the oxide layer the aluminum is already melted. It is the same as taking a plastic bag filled with water and hammering the plastic bag. If the temperature is too high the melted aluminum will splash all over.
Sorry, but I have no photos (I just played with the material and did not make a "work") and I even do not know what type of aluminum it was.

[PTsideshow]

Bill is a master at it, he had some of his work posted on the site with a thread or too.

[Rich Waugh]

You can forge most aluminum cold, once it has been annealed.  To anneal, heat carefully until it will just char a pine stick rubbed against it, then quench in water.  You can forge it hot, but the thermal conductivity is high enough that it cools quickly and transmits lots of heat to the tongs.  A gas forge is the way to fly for aluminum - get it up to a low red heat and turn the burner(s) to a low idle and then watch the stuff like a hawk.  The low red heat is about the melting point of most aluminum.  It forges like butter at heat, and not bad at all cold.  Easy to develop cold shuts if you're not careful a sit can move too far too quickly sometimes.

Bill Roberts will no doubt pop in with some more complete advice, but I suggest that the only way to really learn how to deal with it is to try it out.

Edited by Rich Waugh, 23 August 2011 - 02:51 PM.

[trez]

I have done some and what I have found that works best anneal it and then work it. Have done a little on the power hammer Paint stirrers work great.I have uses a weed burner great control.

[ornametalsmith]

Weeeeeeeeeeeeeeeeeeeee one of my favorite non ferrous metals to forge  
I forge a LOT of it cold without even annealling. But that's another story........   There are a few different ways to tell the proper temperature for forging AND annealilng.
ONE........soot up the aluminum with acet..........then add oxy to the torch and as you heat up the aluminum.....the soot from the acet. will burn off at approx. the same temp as the aluminum anneals. More handy for annealing as opposed to forging.
TWO...the ol paint stick........but even your hammer handle will do......you rub the stick on the cold aluminum....feels like an eraser.....has drag.....leaves no mark. As you heat up the aluminum...and rub the stick on the surface.....it will start to leave a light colored mark and have less drag. As you get hotter the mark gets darker and the stick will feel slippery as you rub the surface. IF  you let the aluminum get TO HOT....and it leaves a smokin' BLACK line..........it's about to melt.......IF you don't jar or hit the aluminum and let it come back down in temp.....you MAY be able to save it. So....in general......I forge at about "dark brown" with the paint stick.
THREE.......Sharpie........the ink burns off at about same temp.

The stick is probably my most used....even use it when sooting to anneal a large piece..........I keep checking the temp by rubbing with the stick. I could go on and on.....but I'll give it a rest........Glad your giving aluminum a try Chris.

[Christopher Rice]

Thanks alot for taking the time to post some info.  Sounds very interesting, I will definately be giving it a try.  I always enjoy learning new things to manipulate in the flame.  I'll let you know how it all turns out.