Aluminum

[jocat54]

I have melted just about everything I could get my hands on--including cans, they are a big waste of time and energy. But I did make the belt conversion for my mini mill(don't have anymore) from mostly cans (mounting plates and both pulleys) and they worked very well and machined just fine.
I really need to go looking for some more scrap, my supply is very low

 

[kvt]

Old alum heads from cars, A pain to cut up but work good, son in law works at a shop and can get me all kinds of old car parts. my problem has been the gas bubbles Have to find what to use to take care of that.

 

[Rustrp]

Generally, re-melting cast aluminium it has worked for me. Casting aluminium from extrusions have not machined well.

I imagine if the extrusions were anodized this could be a problem because the anodized finish is hard, but a cast aluminum part or extruded aluminum part with a mill finish should have no chemical property differences in the same alloy group.

 

[mzayd3]

Old alum heads from cars, A pain to cut up but work good, son in law works at a shop and can get me all kinds of old car parts. my problem has been the gas bubbles Have to find what to use to take care of that.

I've had similar issues. Turns out I was boiling it. Next time I poured at a lower temp and didn't have any issues


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[jocat54]

I've had similar issues. Turns out I was boiling it. Next time I poured at a lower temp and didn't have any issues


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I also found that out and don't stir or skim anymore than absolutely necessary, creates air (gas) bubbles when you do.

 

[MozamPete]

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).

Duraluminum is something like 4% copper. The suggestion I saw was nothing like that much, only a fraction of a %.

 

[rwm]

Alloy compsition is NOT the only thing affecting machinability. The heat treatment / temper has a lot to do with it. Most of the 6061 we machine routinely is solutional treated to T6. I have experimented extensively with this. Additives like TiBor (grain refiner) seem to have little effect. For those of you having issues with porosity you could try a degasser but I have a simpler solution. As soon as you get up to temp and the aluminum starts to melt, add extra air to your burner so the atmosphere in the furnace is oxidizing (not rich, with excess fuel.) The porosity is from dissolved hydrogen. An oxidizing atmosphere helps eliminate this tremendously. Ty it.
Robert

 

[kvt]

Will give it a try, but first I have to redo my setup. It was out and got saturated with water, etc. So I figure I need to make one larger any way, Last one was a 20Lb propane tank with about a 6 in hole in the middle that was not insulated. It could melt AL and the outside could still be touched. Well that was till it filled with garbage and water for a while.

 

[Rustrp]

Alloy compsition is NOT the only thing affecting machinability. The heat treatment / temper has a lot to do with it.

True, but most home foundries, which consist mainly for aluminum do not have the means to facilitate proper tempering so we go with what we have.