Author Topic: A melting pot  (Read 8364 times)

Offline mzt

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A melting pot
« on: December 05, 2012, 01:58:13 PM »

During the past w.e. I had a bit of fun into melting some alu.
Here?s the crucible:




It had a factory made hole right in the middle of the bottom, I filled it using an handful of garden soil (many thanks to the mole
that did the digging works for me). I was pretty sure the seal would have leaked.
It didn?t.



 
I must state I definitely had NO PLANS AT ALL about lifting that ?crucible? from the furnace to pour the molten metal anywhere.
Not even a place to pour it into.
I left the pot into the furnace till it solidified, then grabbed an hammer. So much for the pot.
 



Got curious about machining that stuff. It barely goes into the lathe chuck (gotta borrow some smaller flowerpot if I?m gonna do that again).




It?s nowhere close to a nicely machinable metal: gummy, gives short chips, dust, and builds up on tools edges.
And there were a few hardened steel pins (I had not removed from the HDD frames before melting them) embedded into the smaller end.
Ended with hacksawing a slice about 15mm thick from the top.



 
It takes much less floor space than the ~200 soft drinks cans (+ a couple of HDD frames) it was a few hours before.



 
Made a second, parallel (side by side in the same furnace) attempt using a tin can crucible:  I was pretty sure the tin can
would have worked better than the pot.
It didn?t.



I will wash them clean of the visible soil inclusions, let them dry and re-use the lot on another melt, someday.

Marcello
This is a fitting job,
not a production job that can be measured in.

Arbalest

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Re: A melting pot
« Reply #1 on: December 05, 2012, 05:29:44 PM »

Offline Groomengineering

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Re: A melting pot
« Reply #2 on: December 05, 2012, 08:15:10 PM »
Hey Marcello, looks you did have some fun!  :cartwheel:  If you're going to use pop cans you may want to throw a few small pieces of copper pipe into the melt, 5-8% by weight if you want to bother weighing everything.  Pure Alu (cans, extrusions, lawn chairs, etc) is very gummy, the alloyed copper makes it much easier to work with.  Or use previously cast scrap (pistons, water pumps, etc) that are already alloys.

Be careful with this casting thing, it's very very addicting!  :LittleDevil:

Cheers

Jeff
Success is the ability to go from failure to failure without losing your enthusiasm.

Offline mzt

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Re: A melting pot
« Reply #3 on: December 06, 2012, 12:03:55 PM »
Arbalest,

that BCS site has LOTS of items I would need before I would feel in need of degassing my melts. Thank You for ponting me there.
(Pity the shipping & customs costs from the States would kill).


Jeff,

sure I'm having fun!
I've finally given a start to yet another addiction after years of books reading about the subject: that's scary stuff when read on printed paper, It took a while for me to get around to it.
And, I do not have yet the right equipment I should use (and wear) to play safely with molten metals.
I'm getting to it in very small steps: by now I've fully melted some alu & successfully handled my first (and second) crucible failure.
Next step will probably ask for a more robust crucible, maybe an ingot mold. The furnace itself could do with some improvements, some type of forced ventilation to say one.

As for improving the pop alloy... ..I've filed the advice, but will save the few copper scraps I have for the day I will have a pattern set into a flask.
At the moment I'm happy with reducing the size of my crushed cans pile to limits I can handle: that poor material I get will be eventually re-melted, alloyed, de-gassed... 
..or just used as is to make one off fixtures when machining something else or
Well, I can do with a few alu paperweights.  ;D

Marcello


This is a fitting job,
not a production job that can be measured in.

Offline mzt

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Re: A melting pot
« Reply #4 on: December 10, 2012, 09:30:05 AM »
1st pour!

yesterday morning the shop was cold. While waiting for the stove to bring the room temperature above the freezing point, 
I had the idea of putting a beans can stuffed with alu swarfs into the fire. Some time later the can was red hot and the
swarfs had compacted into pure dross.  I don?t think I will bother with saving alu. swarfs anymore.

I had a few alu. clips taken from soft drinks: when they melted I poured them into a cut off beans can to make an ingot.




Then, I realized I had some use for that ingot, if it were not the only one I had.
Hence the second beans can already set into the sand.




 
While waiting for the second ingot to cool down, I came across a few scraps worth being set into the fire.





Bean cans molds are single use: You?ve to rip them to get the ingot, and I had no more at hand.
I put a layer of (very dry) sand on the already solidified ingot, flattened the cover, placed it over the sand and poured again





Here?s the two ingots.
 




Aint much fond of canned foods :disappointed:, still, if I could spot something coming into a square metal box at the supermarket,
You bet that would do for my lunch! ;D ;D


Marcello
This is a fitting job,
not a production job that can be measured in.

Online Jo

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Re: A melting pot
« Reply #5 on: December 10, 2012, 09:51:25 AM »
Marcello

Did I understand you correctly: You cut up the bits of fizzy drink cans into a tin can, then put this directly into the (Wood burning) fire. I assume covered with something. And then a little while later had an aluminium ingot :cartwheel:.

 :thinking: I may have to start saving my cans as I have a log fire most evenings.

Jo
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Online Jo

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Re: A melting pot
« Reply #6 on: December 10, 2012, 09:54:23 AM »
Just a thought: Its Xmas time there are lots of nice tins around full of shortbread and other niceties that you may need to buy, for those square containers ;).

Jo
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Offline mzt

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Re: A melting pot
« Reply #7 on: December 10, 2012, 10:34:57 AM »
Jo,

I put the aluminium bits into a beans can (which was not aluminium) and set them into my stove (which is all-steel, no refractory. A stove with refractory lining should to better).
Then, I poured the melted alu into another beans can I had set on a bed of sand (the large flowerpot).
I had ideas that melting without pouring, as I did a week ago, gives worse results than when the metal is poured. I still have ideas that pouring into an enclosed mold should bring further improvements to the final product, but I have no flasks, moding sands and a lot of stuff I'd need. (yet)

Beware, a crucible failure is always possible, especially when using tin cans (to say nothing about flowerpots), and in my case a crucible failure when taking the material ouside the stove was (more or less) likely to happen on the sand bed or into the stove itself.  My stove would not suffer if it were splashed with molten alu. from the inside: I'd just collect it when cold into the bottom drawer.

Yes, it was wood burning fire.
There's very little point into saving the drink cans: the flowerpot ingot I made on the start of this thread took about 2 hundreds of them, a several years collection. (But it was less work having them crushed flat under a boot and thrown in a box than taken outside for the trash man to collect them).

Marcello


This is a fitting job,
not a production job that can be measured in.

Online Jo

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Re: A melting pot
« Reply #8 on: December 10, 2012, 10:42:24 AM »

Beware, a crucible failure is always possible, especially when using tin cans (to say nothing about flowerpots), and in my case a crucible failure when taking the material ouside the stove was (more or less) likely to happen on the sand bed or into the stove itself.  My stove would not suffer if it were splashed with molten alu. from the inside: I'd just collect it when cold into the bottom drawer.

 :o Maybe I shouldn't be looking to use my open fire in the Drawing Room to do this then, I don't think my solid Oak floors would appreciate molten aluminium splashes. So heat treatment of metal only in that fire place >:D.

Jo
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Offline mzt

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Re: A melting pot
« Reply #9 on: December 10, 2012, 11:07:40 AM »
Quote
I don't think my solid Oak floors would appreciate molten aluminium splashes

Aint sure of that, but I have ideas it would be safer than a concrete floor.
What if I placed a large metal sheet below the stove & sand area if I were to do 'inside-pouring' again?

And, no: I won't pour into an enclosed mold when not in the open.

Marcello
This is a fitting job,
not a production job that can be measured in.

Offline Groomengineering

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Re: A melting pot
« Reply #10 on: December 12, 2012, 06:07:14 PM »
Short pieces of angle iron welded together in a \/\/\/ pattern with a cap welded on each end make great ingot molds.  :ThumbsUp:

Cheers

Jeff
Success is the ability to go from failure to failure without losing your enthusiasm.

Offline mzt

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Re: A melting pot
« Reply #11 on: December 17, 2012, 02:04:04 PM »
Jeff,

I will get around making a few someday. Do they work for brass/bronze too?
Marcello

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Offline mzt

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Re: A melting pot
« Reply #12 on: December 17, 2012, 02:08:17 PM »
A pop can micrometer stand.



 
There?s a second screw coming into the green teflon clamp from the bottom of the base. The M6 holding screw with the knulred collar
was drilled to accept a Teflon tip, not to mar the mike frame.




A friend of mine gave me a few empty cigar boxes, perfect for pouring squared ingots. After making a few I decided to make a couple
in smaller dimensions by placing a strip of metal into the box. A sharp hammer blow when cold will separate them.


 

Marcello
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not a production job that can be measured in.

Offline zeeprogrammer

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Re: A melting pot
« Reply #13 on: December 17, 2012, 02:56:00 PM »
Pretty cool Marcello. Looks like you've really gotten into this.
I can understand the increased satisfaction when people cast their own metal to make parts.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Zee-Another Thread Trasher.

Offline mzt

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Re: A melting pot
« Reply #14 on: December 17, 2012, 03:43:32 PM »
Quote
I can understand the increased satisfaction when people cast their own metal to make parts.


And when I'm casting my own parts to make engines I will graduate to log a build into "from castings" section. ;D
That's not to come soon, plenty of skills to earn before I will.
Marcello
This is a fitting job,
not a production job that can be measured in.