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Posted (edited)

Yep, Bonny. Don´t ever try to grind it in a plastic-case blade mill by the way! They work well with 50:50, but the 70:30 went straight through the wall :-).

 

I´d love to hear some experiences about the physical properties of 70:30 for comparision. I don´t know if it´s intended to be that hard to break up, or if anything went wrong with my ratios...

Edited by AdmiralDonSnider
Posted

Ready to melt a 1300g batch of MgAl. I spent a lot of time to cut the Al oil pan and the Mg gearbox with one of these big angle grinders. Messy work and this tool is so heavy and powerful. I was totall covered with Mg-Al dust and went to take a shower.

 

http://store.picbg.net/thumb/7E/50/bfc37d6310847e50.jpg

Posted
That sounded like the start to a story about how you accidentally spontaneously ignited. :)
Posted

That sounded like the start to a story about how you accidentally spontaneously ignited. :)

 

You could protect yourself with some potassium dichromate...

Posted
Very kind of you, but I prefer linseed oil :blush:
  • 3 weeks later...
Posted (edited)

Lesson learned when making MgAl guys!

Don't be tempted to melt MgAl in a too long container. I mean, you can, but don't fill it to the top. Denser Al tends to sink to the bottom and lighter Mg goes to the top. Now I have Mixed MgAl, where I can only break the middle part, the top and bottom are inbreakable and I'll melt them again.

By the way, here are some photos of making it with a pepper baker.

 

http://store.picbg.net/thumb/18/94/5c382bf108401894.jpg http://store.picbg.net/thumb/5D/8B/6e6ba876c6195d8b.jpg http://store.picbg.net/thumb/1B/13/072e96dfed911b13.jpg

http://store.picbg.net/thumb/E3/66/862ea5bcb502e366.jpg http://store.picbg.net/thumb/2D/EC/70a7639951292dec.jpg http://store.picbg.net/thumb/02/E5/6b48243a6c1902e5.jpg

http://store.picbg.net/thumb/14/2C/1c6012ca6520142c.jpg

Edited by 50AE
Posted

Lesson learned when making MgAl guys!

Don't be tempted to melt MgAl in a too long container. I mean, you can, but don't fill it to the top. Denser Al tends to sink to the bottom and lighter Mg goes to the top. Now I have Mixed MgAl, where I can only break the middle part, the top and bottom are inbreakable and I'll melt them again.

By the way, here are some photos of making it with a pepper baker.

 

The problem you have is that the material is not mixed properly.The container size/shape, is not the problem. I have experienced the same issue witha wide, shallow container that was not sufficientlty stirred. Very simply, the melt was not well mixed. IIRC correctly I posted this exact problem on here quite some time ago...as per FrankRizzo I would recommend re-melting the whole batch. It is most likely the unbreakable ends contain a larger % of Al, so you want to bring it back to the intended ratio.

Posted
A long handled tea spoon works great in the lead pot for stirring, wouldn't a stainless tea spoon work for this as well?
Posted

A long handled tea spoon works great in the lead pot for stirring, wouldn't a stainless tea spoon work for this as well?

 

A stainless spoon would work , as will a rod (stainless or even clean mild steel)

Posted
I stirred for about half and a minute after everything had melted. Maybe the rod surface has to be in mind. I stirred with a very fin (0.5mm) rod. Gonna attach a spoon to it for next time.
Posted

A stainless spoon would work , as will a rod (stainless or even clean mild steel)

 

You need more surface area then a rod to make a good homogeneous mixture.

  • 3 weeks later...
Posted

I don´t know how many of you have messed around making other alloys than the common 50:50, but for those who plan to do so:

 

I have made 70:30

 

I was under the impression that the 70/30MgAl was 70% Mg....

 

which indeed is 70% magnesium (I was wrong earlier in this thread) and called for in some colored star formulas (in Hardt, Baechle), and 30:70 which is said to be superior for crackling microstars.

 

Both are nightmare to reduce to a fine powder; they´re nowhere near as brittle as 50:50. 30:70, being high on aluminum, is the hardest of the three to grind, but 70:30 is not much better (but is more bulky).

 

I´d appreciate any suggestions how to conveniently reduce these to a useable size. Kitchen macerators work well for the usual alloy, but have a hard and short life with others. I assume that even a ball-mill would have its troubles with 30:70...

  • 1 month later...
Posted

 

I´d appreciate any suggestions how to conveniently reduce these to a useable size. Kitchen macerators work well for the usual alloy, but have a hard and short life with others. I assume that even a ball-mill would have its troubles with 30:70...

 

The way I (rough) break my MgAl up is in a coffee can with a pc of steel shaft (and a bag over top to keep the pcs in the can). Maybe something that would work for you - using a heavier can. After that a (large) ball mill with heavy SS or chrome bearing media.

You also might want to try pouring the alloy melt into water as a few members do, it (might) make it more brittle.

Posted

The way I (rough) break my MgAl up is in a coffee can with a pc of steel shaft (and a bag over top to keep the pcs in the can). Maybe something that would work for you - using a heavier can. After that a (large) ball mill with heavy SS or chrome bearing media.

You also might want to try pouring the alloy melt into water as a few members do, it (might) make it more brittle.

 

Careful of steam explosions if you do this. I do lead shot the same way for Cowboy shoots, if you let too much molten liquid out at once, it boils the water and throws it out of the cooling tank.

 

I use a 5 gallon metal can with the garden hose running full open to keep the water cold.

Posted

The way I (rough) break my MgAl up is in a coffee can with a pc of steel shaft (and a bag over top to keep the pcs in the can).

 

Non-standard alloys such as 70:30 or 30:70 really are different: I hit the ingots with a large hammer and they just kept smiling at me. The problem is that these alloys aren´t brittle at all, they tend to be flexible instead, like the parent materials. Nothing to be crushed easily, really.

Posted

Non-standard alloys such as 70:30 or 30:70 really are different: I hit the ingots with a large hammer and they just kept smiling at me. The problem is that these alloys aren´t brittle at all, they tend to be flexible instead, like the parent materials. Nothing to be crushed easily, really.

 

 

You might be SOL in reducing the particel size by normal/practical means...

Machining/grinding could be your best option.

Maybe you could freeze with nitrogen and then smash :blink:

  • 8 years later...
Posted

Very Cool, nicely done! http://freeimagehost.info/i/EmLd7t6Zzb.png

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