AdmiralDonSnider Posted May 31, 2010 Posted May 31, 2010 Well I´ll try stirring like you do :-). I don´t use charcoal, never considered it necessary - but I guess its absence is not responsible for the bubble formation?
Bonny Posted June 1, 2010 Posted June 1, 2010 Well I´ll try stirring like you do :-). I don´t use charcoal, never considered it necessary - but I guess its absence is not responsible for the bubble formation? I think as long as you mix it well and keep hot for maybe a few minutes after stirring (been awhile since I made any) you should be fine. The charcoal (poured on top- last step) is added to prevent the melt from oxidizing by covering and using up the oxygen before it can oxidize the melt.
Ventsi Posted June 5, 2010 Posted June 5, 2010 Just got 1lb of 99.8%Mg, 16 bux shipped. Time to get cooking. =]
Mumbles Posted June 6, 2010 Posted June 6, 2010 You got ripped off. Try your local scrap yard or metal recycler.
Ventsi Posted June 6, 2010 Posted June 6, 2010 I did, I tried several yards, they all only sold by the ton, there were some cheaper alternatives but I didn't want a 40lb ingot either. I really looked and settled for the lazy solution. Plus I couldn't find any old lawnmower decks. Oh well, at least I'll be able to wear a MgAl badge
mike_au Posted June 7, 2010 Posted June 7, 2010 None of the scrap yards I checked had any either, but I ended up getting about 3.5kg of the stuff for free from a local plumber who makes anodes for hot water systems. He had about 1kg of offcuts and about 2.5kg of old anodes that weren't completely consumed. The old ones were caked in some sort of mineral deposit or oxides or something, but they cleaned up quickly with a wire wheel.
Bonny Posted June 8, 2010 Posted June 8, 2010 Just got 1lb of 99.8%Mg, 16 bux shipped. Time to get cooking. =] Still a nice looking chunk of Mg though. The only PITA I see is cutting it up (unless you have a bandsaw). The first few batches of MgAl I made were from dirtbike/motorcycle valve or chaincase covers and were not very cheap, but they were easily smashed into smaller pcs for melting.
Peret Posted June 9, 2010 Posted June 9, 2010 Has anyone tried using one of these vibratory mills? $60 at Harbor Freight. With the wicked looking ceramic media they sell (for "aggressive metal removal") it looks as if it might do a better job on magnalium than a ball mill.
Bonny Posted June 9, 2010 Posted June 9, 2010 Has anyone tried using one of these vibratory mills? $60 at Harbor Freight. With the wicked looking ceramic media they sell (for "aggressive metal removal") it looks as if it might do a better job on magnalium than a ball mill. Although I've never tried one, I don't think a vibratory mill would work very well, if at all for grinding MgAl, or most things. A ballmill works by rolling/crashing the media onto the particles, rather than simply vibrating and rubbing them together. I think those kind of mills are for polishing and deburring.
50AE Posted June 18, 2010 Posted June 18, 2010 (edited) I made my first batch of MgAl, 540 grams!As most things I do for the first time, I'm very happy with it. It's very shiny, brittle and sharp stuff. It squeaks when pressed, small pieces easily snap using my fingers.Maybe gonna post pics tomorrow, if I haven't broken it till then Edit: Here they are http://store.picbg.net/thumb/C8/B5/eac49707d140c8b5.JPG http://store.picbg.net/thumb/C9/C7/09ce043bed13c9c7.JPG Edited June 19, 2010 by 50AE
Ventsi Posted August 9, 2010 Posted August 9, 2010 Damn, I was just getting to start looking for one off those pepper bakers, with my dad, when all the sudden he gave himself a nice facepalm. Over here everything is meant for 220V in the US its 110V, I have a few transformers but those are rated for 80 watts while this thing probably goes near a thousand. Damn indeed...
50AE Posted August 9, 2010 Posted August 9, 2010 You can wind one pepper baker yourself, though it's not something that can be done at home. You have to cover it with clay and bake it at high temperature.If you can get a more powerful baker, like 2,4kW or something, powering it at 110W should divide the received power in half. 1,2kW should be enough to melt MgAl. As for me, today I went to the scrapyard and I found a VW Mg gearbox cover. I was in good mood, but when I returned home and took a good look at it, I understood how dirty it was. It's old, has 1cm thick dirty mix of oil, dirt and maybe shit (it smells horribly). But I think I'll handle it .It weights 6,6kg. I searched in google about Mg VW parts, and it seems they are AZ91D alloy. It contains 8,5 to 9,5% Al and max 0,9% zinc.
Algenco Posted August 9, 2010 Posted August 9, 2010 I made my first batch of MgAl, 540 grams!As most things I do for the first time, I'm very happy with it. It's very shiny, brittle and sharp stuff. It squeaks when pressed, small pieces easily snap using my fingers.Maybe gonna post pics tomorrow, if I haven't broken it till then Edit: Here they are http://store.picbg.net/thumb/C8/B5/eac49707d140c8b5.JPG http://store.picbg.net/thumb/C9/C7/09ce043bed13c9c7.JPG Looks great, I have everything I need, just waiting for cooler weather, too hot to be outside long
Bonny Posted August 9, 2010 Posted August 9, 2010 You can wind one pepper baker yourself, though it's not something that can be done at home. You have to cover it with clay and bake it at high temperature.If you can get a more powerful baker, like 2,4kW or something, powering it at 110W should divide the received power in half. 1,2kW should be enough to melt MgAl. As for me, today I went to the scrapyard and I found a VW Mg gearbox cover. I was in good mood, but when I returned home and took a good look at it, I understood how dirty it was. It's old, has 1cm thick dirty mix of oil, dirt and maybe shit (it smells horribly). But I think I'll handle it .It weights 6,6kg. I searched in google about Mg VW parts, and it seems they are AZ91D alloy. It contains 8,5 to 9,5% Al and max 0,9% zinc. Just give it a soak and then a good scrub with a wire brush in a strong alcohol or solvent - mineral spirits/varsol/turpentine or something similar, but really, for cleaning engine parts gasoline is great.
mfstraydog1 Posted August 11, 2010 Posted August 11, 2010 does the type of AL afect the magnalium. what i mean by type of AL is T1- T6
mike_au Posted August 11, 2010 Posted August 11, 2010 does the type of AL afect the magnalium. what i mean by type of AL is T1- T6 T1-T6 refers to how the metal is tempered, it is going to be melted down, so no that isn't important. If possible you should try to account for the Mg in the alloy when working out your ratio.
Bonny Posted August 11, 2010 Posted August 11, 2010 T1-T6 refers to how the metal is tempered, it is going to be melted down, so no that isn't important. If possible you should try to account for the Mg in the alloy when working out your ratio. It's also important (more so IMO) to try and account for the Al (and possibly other metals) in the Mg, as most Mg found as scrap is not pure. I usually blend mine 60:40 Mg:Al. The Al I use is from wire which is generally very pure.
50AE Posted August 11, 2010 Posted August 11, 2010 Does anyone have any idea from what cast Al alloy WV engine oil pans could be? I got one from a guy, who claims he tried to weld it, but it wasn't weldable, slightly burning and leaving flying white particles (indicating presence of Mg or Zn).
Algenco Posted August 11, 2010 Posted August 11, 2010 Does anyone have any idea from what cast Al alloy WV engine oil pans could be? I got one from a guy, who claims he tried to weld it, but it wasn't weldable, slightly burning and leaving flying white particles (indicating presence of Mg or Zn). I was told by a mechanic that VW engines were Magnesium, try the vinegar/acid test, if it reacts it's Mag
AdmiralDonSnider Posted August 11, 2010 Posted August 11, 2010 A few quick questions: - does anyone have an idea how much metal in % (mostly Mg) is approximately lost due to oxidation/burning during the alloying process (even when keeping the pot shut as much as possible)? Do you compensate by adding more of one metal? - how much more reactive is 70/30 (i.e. 70% Al) compared to 50/50? I knew that 70/30 is preferred for dragons eggs, but today when I made my first batch of it, it also turned out oxidizing much more fiercly, the whole surface burning in a yellow flame (while 50:50 does oxidize showing a few white flame spots). Any ideas or chemical explanations? @50AE: I´m using AZ91. You want roughly 45% Al and 55% AZ91 to account for the Al in the AZ.
50AE Posted August 11, 2010 Posted August 11, 2010 (edited) I'll be using AZ91 as Mg source as well, but you didn't get my point.As Al source, I have a VW engine oil pan, which I described in the previous post. I wonder what alloy it could be. I just want to be assured that it doesn't contain much silicon. @admiral: How much Mg is lost in % will depend of the exposed surface and the amount of MgAl you are making at a time. For example, you will loose more Mg when preparing 100g instead of 1kg. But I think you shouldn't care about this. Edited August 11, 2010 by 50AE
Peret Posted August 12, 2010 Posted August 12, 2010 There are alloys, and there are intermetallic compounds. "The intermetallic compound Mg4Al3 (54% Mg by weight) has a heat of formation of +49kcal/mole; its density is 2.15 and its melting point 463C. This alloy is advantageously different from the corresponding mixtures of magnesium and aluminum in that it has a lesser tendency to corrode, and its brittleness is greater, so that it can be ground up easily." - Shidlovskiy I believe this is the alloy you generally get from pyro suppliers.
AdmiralDonSnider Posted August 12, 2010 Posted August 12, 2010 As Al source, I have a VW engine oil pan, which I described in the previous post. I wonder what alloy it could be. I just want to be assured that it doesn't contain much silicon. @admiral: How much Mg is lost in % will depend of the exposed surface and the amount of MgAl you are making at a time. For example, you will loose more Mg when preparing 100g instead of 1kg. But I think you shouldn't care about this. Wouldn´t the Si content be negligibly small anyway? I wonder why you´re using (dirty?) motor parts - Al can be easily found in any imaginable form, sheets, window frames etc. I will loose more Mg with more exposed surface but I assume the rough percentage lost will remain about constant. One could easily account for the loss by adding e.g. 5% Mg by default. I wonder if there is also a loss of Al due to oxidation/burning metal? Today I ground up my first ingot of 70/30 and found that this can be nightmare, as this alloy is much less brittle and thus much harder to pulverize. My blade mill also had a hard job...
Bonny Posted August 12, 2010 Posted August 12, 2010 Wouldn´t the Si content be negligibly small anyway? I wonder why you´re using (dirty?) motor parts - Al can be easily found in any imaginable form, sheets, window frames etc. I will loose more Mg with more exposed surface but I assume the rough percentage lost will remain about constant. One could easily account for the loss by adding e.g. 5% Mg by default. I wonder if there is also a loss of Al due to oxidation/burning metal? Today I ground up my first ingot of 70/30 and found that this can be nightmare, as this alloy is much less brittle and thus much harder to pulverize. My blade mill also had a hard job... I would assume it would be much harder to break up with that much Al. I was under the impression that the 70/30MgAl was 70% Mg....
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