Aluminum

dlane

dlane

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just wondering about what types of al are desirable for remelting and machinable /weldable?.
Dose melting it change its properties , or can stuff be added to it to change it ?.
Extruded house window frames , pistons, cans , rims , wheelchair / bike frames , and whatever
Can you tell what type it is by fileing ?
Thanks
 
dlane said:
just wondering about what types of al are desirable for remelting and machinable /weldable?.
Dose melting it change its properties , or can stuff be added to it to change it ?.
Extruded house window frames , pistons, cans , rims , wheelchair / bike frames , and whatever
Can you tell what type it is by fileing ?
Thanks
Click to expand...

If you want the chemical properties the same then keep the different products separate. Most extrusions fall into the 6061-6063 alloys group, and cans are 2000-3000 alloy, but most Al. cans today are formed from the 3000 alloy group. If it fills a structrual need then it's probably a 6000 group but the myriad of other products are always a shot in the dark. If any of the new F150's in your area begin missing body parts we will know you have your foundry up and running. :big grin:

PS. I know the debates run wild on what alloy Ford uses but they only say military grade Al. which some think it's 6061-6063 but it could be any alloy since the military uses them all.
 
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The "best" casting alloys are high Si alloys like A356. Car wheels and cast pistons are good sources. Cans are crap and not worth using. The machinability of castings is not good unless you heat treat the castings. Treating to a T6 temper really changes the machinability. You can add Si to extrusions to improve them but they aren't too bad unless the mold is complex with thin parts. You cannot tell the alloys apart without an XRF. Check your metals with vinegar to make sure they are not Mg. If you get a crucible of Mg on fire you will not be able to put it out and it will destroy your furnace.
Robert
 
Magnesium fires can be put out by smothering with sand. Water and burning magnesium creates hydrogen. A bucket or two of sand is a good thing to have in a foundry area.

A dry chemical or CO2 extinguisher will also work on smaller fires. The object is to remove oxygen from the vicinity.
 
dlane said:
Dose melting it change its properties , or can stuff be added to it to change it ?
Click to expand...

Melting doesn't change properties unless the heat is excessive. Now adding to the mix to change properties would be a shot in the dark since you don't know what you are beginning with, and most alloys added are usually measured in points. e.g. .4%-.8%

Tubalcain has a few aluminum casting projects he incorporates into other tasks, like lathe alignment tool used for setup when turning between centers. The castings could just as well be substituted by using a couple of pieces of round stock but he's including two or three lessons in one task.


PS. The aluminum cans have the best value recycled so you can use the funds for the other projects.
 
I remember seeing somewhere (YouTube video I think) a suggestion to add a small amount of copper tube to the aluminum melt - From memory it was to increase the silicon content and make melted extruded and bar stock type aluminium cast better. It was only a small amount of copper, something like an inch length of 1/2' tube to a reasonably large crucible of aluminium.
 
MozamPete said:
I remember seeing somewhere (YouTube video I think) a suggestion to add a small amount of copper tube to the aluminum melt ...
Click to expand...

The addition of copper stiffens the alloy, makes it age-hardening: it was called
Duraluminum. Unfortunately, this is bad for corrosion (and such alloys
in marine use turn to white dust over time).
 
Generally, re-melting cast aluminium it has worked for me. Casting aluminium from extrusions have not machined well.
 
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