Hi,

I got some decent crucible tongs and a pouring ring fabricated, and
tried my first alunimum melt today in my home made foundry.

Everything went well, I melted a few hundred coke cans and fished out a
ton of dross, and was left with a few pounds of good aluminum.

I'm having a problem with my ingot molds though. I first tried a
standard 6 cup muffin tin for my test melt of lead, and one of the lead
ingots soldered itself to the bottom, requiring me to mangle up the tin
to get it out.

So for this Alumnium melt, I got a new tin, this one made from
stainless steel, with 24 tiny muffin indents. I figured the smaller
ingot size and the stainless steel should keep the aluminum from
sticking.

I was wrong. I now have 12 tiny aluminum ingots soldered firmly to the
stainless steel mold. I didn't even thing aluminum would stick to
stainless.

If it comes to it, I can always make clay molds out of rammed cat
litter, but I really liked the idea of using a muffin tin.

Any ideas?

IMHO the cheapest easiest ingot molds are made out of angle iron or
channel iron. If you have an electric welder, they are easy to make
and cheap and sticking will not be a problem. Cut ends of angle iron
or channel irons on an angle of approc 3 to 5 deg for draft, and weld
on a piece of strap or flat iron. You can gang a couple of them
together. Extend the flat iron thats used to cover the ends of the
channel or angle iron and attach a p iece of rod or pipe to it so it
forms a handle.....Works great and takes a beating.

Or if you have green sand you can simply inbed a ingot pattern or
whatever into the green sand and pour them that way, of course you
have ot make a new mold for each ingot, but if your not doing a lot of
ingots its not a big problem.

You'll soon find cans and other thin materials are bit the greatest
for melting due to all the surface area and tons of dross you get, but
hey, its certainly better than twiddling your thums with nothing at
all to melt down........

regards
'

On 19 Jun 2005 11:03:23 -0700, wrote:

===Hi,
===
===I got some decent crucible tongs and a pouring ring fabricated, and
===tried my first alunimum melt today in my home made foundry.
===
===Everything went well, I melted a few hundred coke cans and fished out a
===ton of dross, and was left with a few pounds of good aluminum.
===
===I'm having a problem with my ingot molds though. I first tried a
===standard 6 cup muffin tin for my test melt of lead, and one of the lead
===ingots soldered itself to the bottom, requiring me to mangle up the tin
===to get it out.
===
===So for this Alumnium melt, I got a new tin, this one made from
===stainless steel, with 24 tiny muffin indents. I figured the smaller
===ingot size and the stainless steel should keep the aluminum from
===sticking.
===
===I was wrong. I now have 12 tiny aluminum ingots soldered firmly to the
===stainless steel mold. I didn't even thing aluminum would stick to
===stainless.
===
===If it comes to it, I can always make clay molds out of rammed cat
===litter, but I really liked the idea of using a muffin tin.
===
===Any ideas?


==============================================
Put some color in your cheeks...garden naked!
"The original frugal ponder"
~~~~ }((((o ~~~~~~ }{{{{o ~~~~~~~ }(((((o

Any idea for getting the aluminum ingots out of the muffin pan? I
tried a torch to the bottom, but all I have is a little bernzomatic
oxy/mapp thing (and various propane torches, including the foundry
burner), and it didn't seem to do much.

The individual cups are crimped into place, and prying on the ingot
actually popped the whole cup out. I guess if it comes down to it I
can melt the cup with the ingot in the foundry when I want to use them,
then fish the cup out.

CHAR YOUR INGOT MOLDS THE FIRST TIME PEOPLE!!!!!!!!!

Sorry but honestly, what the hell makes people pour into a virgin muffin tin
that is designed for cooking food, not metal. The paint (ESPECIALLY if
teflon coated, try that poison on for size) burning off under the metal is
just BEGGING for an explosion.

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

wrote in message
oups.com...
Hi,

I got some decent crucible tongs and a pouring ring fabricated, and
tried my first alunimum melt today in my home made foundry.

Everything went well, I melted a few hundred coke cans and fished out a
ton of dross, and was left with a few pounds of good aluminum.

I'm having a problem with my ingot molds though. I first tried a
standard 6 cup muffin tin for my test melt of lead, and one of the lead
ingots soldered itself to the bottom, requiring me to mangle up the tin
to get it out.

So for this Alumnium melt, I got a new tin, this one made from
stainless steel, with 24 tiny muffin indents. I figured the smaller
ingot size and the stainless steel should keep the aluminum from
sticking.

I was wrong. I now have 12 tiny aluminum ingots soldered firmly to the
stainless steel mold. I didn't even thing aluminum would stick to
stainless.

If it comes to it, I can always make clay molds out of rammed cat
litter, but I really liked the idea of using a muffin tin.

Any ideas?

wrote:
Any idea for getting the aluminum ingots out of the muffin pan? I
tried a torch to the bottom, but all I have is a little bernzomatic
oxy/mapp thing (and various propane torches, including the foundry
burner), and it didn't seem to do much.

The individual cups are crimped into place, and prying on the ingot
actually popped the whole cup out. I guess if it comes down to it I
can melt the cup with the ingot in the foundry when I want to use them,
then fish the cup out.


As Roy said, use a heavier mold to start with and use a better quality
of scrap. Stuff like beer cans is very inneficient scrap, even when done
on industrial levels with baled or briquetted cans. The bottom half of
the cans is good stuff, but the tops are a crummy alloy that you'll
probably find to be quite slushy.

If your mold gets too hot the aluminum will bond with it, either through
warpage or like brazing. Even iron, given some time, will dissolve in
aluminum and I think what you're getting is your ingots effectively
brazed to the muffin tins. A heavier mold won't get to as high a
temperature and you'll likely get better results.

John

"JohnM" wrote in message
...
wrote:
As Roy said, use a heavier mold to start with and use a better quality
of scrap. Stuff like beer cans is very inneficient scrap, even when done
on industrial levels with baled or briquetted cans. The bottom half of
the cans is good stuff, but the tops are a crummy alloy that you'll
probably find to be quite slushy.

Nah, the cans overall melt to approx. 3% Mg, balance Al. Which... really
isn't very useful anyway. Burn out 1-2% of the magnesium, add 1-2% copper
and 10% silicon and you've got yourself a skookum casting alloy. Just need
to find silicon...

There's a *lot* of metal in cans, more than you'd think. I mean, individual
cans are ****-poor on metal, but more than half the slag still contains
metal. To get it out, you need to add a flux. Salt is a good flux for
aluminum, or better yet, a lower-melting mixture such as half and half NaCl
+ KCl (potassium). Throw it on, stir, wait for the salt to melt, add enough
that it becomes a soupy mess, then pour everything. If you want aluminum
oxide for any reason, it can be seperated from the salt by soaking in water.

If your mold gets too hot the aluminum will bond with it, either through
warpage or like brazing.

I'd be more inclined to call it soldering.. it's a pretty weak bond.
'Course it won't get a bond in the first place if your steel is rusty or
covered in scale, which is why you need to char your steel items before any
contact with aluminum.

Even iron, given some time, will dissolve in aluminum

Doesn't take much time, pure aluminum eats non-charred soup cans for
breakfast. At 1450°F, aluminum has about 4% solubility for iron (which
later comes out as brittle Al13Fe4 or if silicon is present, a three
component AlFeSi intermetallic).

and I think what you're getting is your ingots effectively
brazed to the muffin tins. A heavier mold won't get to as high a
temperature and you'll likely get better results.

My 1/4" thick angle iron regularly gets red hot, the problem is how clean
the interface is. I use the damn rustiest angle in my scrap pile and there
ain't a damned thing gonna stick to it.

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

Muffi8n "tins" like soup cans are iffy at most when using them as
crucibles or ingot molds, charred or not. They do not take any kind of
rap without denting, so those dents can also impede removing ingots
from a muffin tin. The cast iron corn bread molds work fine, if you
don't mind having a heap of ingots looking like a slice of corn on the
cob etc. Tin is just too thin and it reacts too much with what poiured
in there other than cake or muffin batters.......

I quit melting cans a long time ago its just not worth it, having to
diddle around to make what you get worthwhile with or without flux,
best to sell the cans and get the money.....or trade them for some
previously cast aluminum scrap.......



On Sun, 19 Jun 2005 16:46:32 -0500, "Tim Williams"
wrote:

===CHAR YOUR INGOT MOLDS THE FIRST TIME PEOPLE!!!!!!!!!
===
===Sorry but honestly, what the hell makes people pour into a virgin muffin tin
===that is designed for cooking food, not metal. The paint (ESPECIALLY if
===teflon coated, try that poison on for size) burning off under the metal is
===just BEGGING for an explosion.
===
===Tim


==============================================
Put some color in your cheeks...garden naked!
"The original frugal ponder"
~~~~ }((((o ~~~~~~ }{{{{o ~~~~~~~ }(((((o

Tim Williams wrote:
"JohnM" wrote in message
...

wrote:
As Roy said, use a heavier mold to start with and use a better quality
of scrap. Stuff like beer cans is very inneficient scrap, even when done
on industrial levels with baled or briquetted cans. The bottom half of
the cans is good stuff, but the tops are a crummy alloy that you'll
probably find to be quite slushy.


Nah, the cans overall melt to approx. 3% Mg, balance Al. Which... really
isn't very useful anyway. Burn out 1-2% of the magnesium, add 1-2% copper
and 10% silicon and you've got yourself a skookum casting alloy. Just need
to find silicon...

Or.. you could start with a different alloy;-)


There's a *lot* of metal in cans, more than you'd think. I mean, individual
cans are ****-poor on metal, but more than half the slag still contains
metal. To get it out, you need to add a flux. Salt is a good flux for
aluminum, or better yet, a lower-melting mixture such as half and half NaCl
+ KCl (potassium). Throw it on, stir, wait for the salt to melt, add enough
that it becomes a soupy mess, then pour everything. If you want aluminum
oxide for any reason, it can be seperated from the salt by soaking in water.

Again, I think I'd start with heavier chunks.. although the oxide might
be useful. Seems a can is about an ounce, and there's a lot of surface
area there to oxidize..



If your mold gets too hot the aluminum will bond with it, either through
warpage or like brazing.


I'd be more inclined to call it soldering.. it's a pretty weak bond.
'Course it won't get a bond in the first place if your steel is rusty or
covered in scale, which is why you need to char your steel items before any
contact with aluminum.

Maybe a coating of carbon from a torch? Careful with the rusty steel, a
little water makes for impressive results. The aluminum foundry I worked
in had some fairly large water cooled sow molds, around 600lb. ingots..
when they'd accidentally pour a wet mold the aluminum would hit the roof
pretty hard, about 20' above. The help would scatter amidst considerable
verbal abuse directed at whoever slipped up, the aluminum would continue
to run, etc. It was sort of a hoot, when nobody got burned.



Even iron, given some time, will dissolve in aluminum


Doesn't take much time, pure aluminum eats non-charred soup cans for
breakfast. At 1450°F, aluminum has about 4% solubility for iron (which
later comes out as brittle Al13Fe4 or if silicon is present, a three
component AlFeSi intermetallic).

Now that you mention it, I remember a guy who liked to throw coathangers
and or banding in the melt when the iron content was adequately low and
they were waiting to bring the alloy to spec., didn't take long for them
to dissolve. The point was simply to increase the number of pounds in
the furnace cheaply.



and I think what you're getting is your ingots effectively
brazed to the muffin tins. A heavier mold won't get to as high a
temperature and you'll likely get better results.


My 1/4" thick angle iron regularly gets red hot, the problem is how clean
the interface is. I use the damn rustiest angle in my scrap pile and there
ain't a damned thing gonna stick to it.

With small ingots I think you're onto something. Again, most of my
experience is with ingots of 25lbs. and up- these have adequate size to
shrink considerably, relative to the mold, and would come out of a clean
mold fairly well. Usually..

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

~Roy~ wrote:

IMHO the cheapest easiest ingot molds are made out of angle iron or
channel iron.

Been there. Works great. I used some angle iron (40 * 40mm), welded them
side by side to have something like a shuffle board and closed the ends
with a flat. No prepping before poring. The steel was HRS.

Nick
--
Motormodelle / Engine Models
http://www.motor-manufaktur.de
todays SPAMfeed: 

"~Roy~" wrote in message
...
snip----

You'll soon find cans and other thin materials are bit the greatest
for melting due to all the surface area and tons of dross you get, but
hey, its certainly better than twiddling your thums with nothing at
all to melt down........


True, but their value as scrap is greater than the yield. Seems to me a
guy could come out much better by selling the cans and buying scrap cast
aluminum, perhaps from the same source. Still leaves you with the *fun*
of melting and casting ingots, but without the tremendous loss. The bonus
is to end up with aluminum formulated perfectly for casting, very unlike
melted cans.

The other thing I'd comment on is using ANYTHING with a thin wall for a
mold. Muffin tins are that, muffin tins. The idea of using them for
molds for molten metal is insane. As Roy said, it's way too easy to make a
mold that won't over heat, preventing your metal from fusing. Using
angle or channel iron is especially good, because the mill scale makes
bonding of the molten metal all the more difficult. If you find you're
having trouble with fusing, you can easily blacken the mold with an
acetylene torch, or brush on a mold release mode of lamp black. Foundry
supplies carry that product.

Harold

wrote:

Hi,

I got some decent crucible tongs and a pouring ring fabricated, and
tried my first alunimum melt today in my home made foundry.

Everything went well, I melted a few hundred coke cans and fished out a
ton of dross, and was left with a few pounds of good aluminum.

I'm having a problem with my ingot molds though. I first tried a
standard 6 cup muffin tin for my test melt of lead, and one of the lead
ingots soldered itself to the bottom, requiring me to mangle up the tin
to get it out.

So for this Alumnium melt, I got a new tin, this one made from
stainless steel, with 24 tiny muffin indents. I figured the smaller
ingot size and the stainless steel should keep the aluminum from
sticking.

I was wrong. I now have 12 tiny aluminum ingots soldered firmly to the
stainless steel mold. I didn't even thing aluminum would stick to
stainless.

If it comes to it, I can always make clay molds out of rammed cat
litter, but I really liked the idea of using a muffin tin.

Any ideas?


My brain is like swiss cheese these days but I seem to remember something about laying down a layer of soot from an acetylete torch to act as a mold release. Not sure how the carbon might affect future melts if it doesn't brush off though. Anyone remember where soot was used like this? Also curious also how it would affect the AL on future melts. Comments?

Koz

Harold and Susan Vordos wrote:

"~Roy~" wrote in message
...
snip----

You'll soon find cans and other thin materials are bit the greatest
for melting due to all the surface area and tons of dross you get, but
hey, its certainly better than twiddling your thums with nothing at
all to melt down........



True, but their value as scrap is greater than the yield. Seems to me a
guy could come out much better by selling the cans and buying scrap cast
aluminum, perhaps from the same source. Still leaves you with the *fun*
of melting and casting ingots, but without the tremendous loss. The bonus
is to end up with aluminum formulated perfectly for casting, very unlike
melted cans.

Very true. My scrapyard will pay about $1.30/lb
for cans and sells me diesel pistons for less than
a dollar a pound. Any day, every day.

Which would you rather cast with?

I seem to remember
something about laying down a layer of soot from an acetylete torch to
act as a mold release.
Koz

Soot from any source has been a standard mold release for many people
who mold lead figures and lead bullets. The "smoked" mold can have the
soot applied with a candle or a torch set rich. It works very well and
most of the soot remains on the mold.

Thanks for the many tips guys. I'll get some cast iron cornbread molds
and will smoke them up with a rich torch first.