Purchasing aluminium stock

[Inferno]

Around here I've been paying $2.50-$3 per pound from second hand sellers. I don't know what I'm paying for new stuff. Never calculated weight because I buy it by the foot.

 

[rwm]

I do sometimes wish I was set up to smelt aluminum because there has been a couple of times that would have been a worthwhile process. I picked up a gym grade treadmill off CL for free and the super HD frame was all aluminum and was at least 120lbs stripped of everything just the aluminum. I ended up having to pay to have it hauled away.

Home cast aluminum generally does not machine well. I much prefer commercial extruded bar stock with T6 temper.

 

[projectnut]

In our area the used equipment dealers sell aluminum for between $2.00 and $3.00 a pound depending on the quantity you purchase. They don’t care what the profile is. Steel is between $1.50 and $2.00 per pound regardless of profile

Metal vendors usually sell by the foot with different profile’s having different prices. When calculated out the used equipment dealers are about 1/2 the price of the metal vendors

Like many others i buy what I think I can use down the road. I usually have close to a ton of various grades of aluminum and and about the same amount of various grades of steel

 

[Janderso]

If you need drops the best source I've found is Ebay.
Example.
McMaster Carr, 6061 T6, 11' diameter x 1" thick is $128 plus shipping.
Ebay has a 11" x 1.25" 6061 for $35 but they want $48 shipping. Still money ahead.
Just 2 cents worth.

 

[RJSakowski]

Home cast aluminum generally does not machine well. I much prefer commercial extruded bar stock with T6 temper.

I have not had a problem with machining home cast aluminum. It does tend to be porous though. I use it for larger non-critical pieces where it is impractical to buy a small quantity of 6061 for a specific job. I save cast aluminum, mostly small engine block and outboard motor blocks. The silicon in cast aluminum increases the fluidity of the molten aluminum.I have 300 -400 lbs of the stuff..

 

[Provincial]

When buying drops, remember that if you are buying something larger than you need, you are paying for the chips in the pan, plus your time/wear and tear/electricity to convert them from solid material.

I avoid material that is unidentified, unless it shows evidence of having been machined in its present state. 6061-T4 and T6 machine well. Some other alloys can be machined with proper procedures. Others can be difficult or impossible to machine or get a decent finish. Soft alloys are especially hard to machine.

Some alloys can be welded easily, some with difficulty, and some not at all. Most lose temper if welded, but some retain adequate strength around the weld to be acceptable if designs consider this.

Some things, like aluminum pipe flanges, are so inexpensive that it is not worth making them from scratch.

 

[Provincial]

I have not had a problem with machining home cast aluminum. It does tend to be porous though. I use it for larger non-critical pieces where it is impractical to buy a small quantity of 6061 for a specific job. I save cast aluminum, mostly small engine block and outboard motor blocks. The silicon in cast aluminum increases the fluidity of the molten aluminum.I have 300 -400 lbs of the stuff..

Alloy 351 used to the the best alloy for sand casting aluminum. That was the case 60 years ago, and there are probably better alloys out there now, but a sand casting from that era is likely to be quite good.

Aluminum motor blocks can have sophisticated alloys. The blocks from the Chevy Vega were famous for having an alloy that was supposed to allow the piston rings to run directly on the cast aluminum bores. One can only imagine what the engineers specified in the attempt to do that! They failed badly, too.

Are your outboard motor blocks made with the permanent mold process? I believe the alloys for that may not perform as well when castings are poured with gravity instead of pressure.

 

[Inferno]

Aluminum motor blocks can have sophisticated alloys. The blocks from the Chevy Vega were famous for having an alloy that was supposed to allow the piston rings to run directly on the cast aluminum bores. One can only imagine what the engineers specified in the attempt to do that! They failed badly, too.

Vega didn't have aluminum piston walls for long. They sleeved them after 74, I think.
My mother replaced her 74 aluminum bore with a 75 sleeve bore. The ridge on the aluminum bore was almost .040 with only 50K on the clock.

 

[rwm]

I have not had a problem with machining home cast aluminum. It does tend to be porous though. I use it for larger non-critical pieces where it is impractical to buy a small quantity of 6061 for a specific job. I save cast aluminum, mostly small engine block and outboard motor blocks. The silicon in cast aluminum increases the fluidity of the molten aluminum.I have 300 -400 lbs of the stuff..

I don't have trouble cutting it, I just never get a very good finish. I have tried all kinds of alloys. I have no idea if others are just less picky about the finish or I am doing something fundamentally wrong.

 

[mmcmdl]

Have about 300 lbs or so of 80/20 extrusion here at the moment . Scrap yard gives me 88 cents per pound . Cost new is outrageous . I'll hide it up in top of the garage for future use .