Hi,

just have to share the excitement. Last weekend I finally
finished all the accessories to do a melt, and fired up the
foundry!! For safety, I melted a very small amount of aluminum,
and cast it. It melted in about 15 minutes and I left it in for
another 5 to pour at a higher temperature. Casting didn't
quite work (sprue too thin, sand too wet) but I'm learning
from my mistakes.

I'm thinking of casting sculptures and parts for a Gingery
Lathe. What is the interest out there for rough castings for
such a lathe? I've built the foundry a bit bigger than the
charcoal foundry, so I can make a longer or thicker bed...

The other thing is the resulting cast seemed a bit soft...
I've looked through the archives and heat treating the cast
seems like a bit of a pain. Would a longer sprue make the
cast denser/harder? Or is it just the lawn chair aluminum
that's not too great for this?

Thanks,
Tom.
http://www.TomEberhard.com

Tom,

Your cheapest bet for good casting material is to use sand-cast
aluminum scrap such as cylinder heads, transmission housings,
differential housings, etc. of OLDER cars where these were indeed
sand-cast.

You can usually tell a sand casting by its characteristic rough surface
where unmachined. Unfortunately modern cars have most of their drive
line housings made of die castings, which are less suitable for
subsequent sand casting.

Drawn material such as tubing, wire, architectual extrusions, etc. will
be very soft after casting since these alloys get their strength
through cold drawing and/or subsequent heat treating. This is a big
subject.

If you stick to basics as described above you should be OK. Try to get
some degassing tablets to reduce porosity thus improving structural
integrity.

Hope this helps a little.

Wolfgang

Congratulations on the foundry. Since I started to fool with mine it
has opened up a whole new arena to make things.....that otherwise
would have involved a lot of chip making and time.

The interest in gingery stuff varies from forum to forum. SOme foks
seem to think its still a homebrew mediocre lathe or what have you ,
and others swear by them. The way I look at Gingery is its a means of
producing somehting thsat works and get some actual hands on
experieince doing it, and have something in the end that will work,
maybe not as good as a factory ade machine,m but still certainly
better than no machine at all. I made the shaper mainly for the need
to cut internal keyways.....and it gave me something to occupy my time
and mind with in the process. Its not used a lot, but its certainly
handy.....A little imagination and forethought and most if not all of
ginery machines can be improved a great deal, but that was not his
intentions as much as keeping things simple and effective....

I owuld have to say its the aluminum you used to do your pour that
resulted in its hardness. Look for items made out of 356.x alloy for
best results. Old cast aluminum items like BBQ grills, small motors,
cylinder heads etc are all very good materials to use for sand
casting. Aluminum siding, windows, doors, gutters, soda cans, wire,
furniture etc leave a lot to be desired, but its still possible to
use this material for some items. Another alloy 319 is also great. 356
alloy will over time harden up some or age, and it can be heat treated
IIRC but heat treat is kind of expensive if you have to farm it out. I
acquire any and all aluminum, separate it into types, extrusions,
sheet, cast etc, and keep all cast type, and carry the blance to the
scrap yard and sell it and buy known cast alum scrap in return......or
if the need is there buy a known certified ingot from the local
smelters.
The sprue in general need not be any longer than 1.5 to 2x its
diameter. Sometimes a larger sprue may help in keeping voids out of a
casting while its chilling down, but its rare i have ever needed a
sprue much over 1" in diameter no matter what it was that I was
casting.

check out my home foundry at http://frugalmachinist.com

Regards


On 23 Nov 2005 07:39:28 -0800, "Tom" wrote:

===Hi,
===
===just have to share the excitement. Last weekend I finally
===finished all the accessories to do a melt, and fired up the
===foundry!! For safety, I melted a very small amount of aluminum,
===and cast it. It melted in about 15 minutes and I left it in for
===another 5 to pour at a higher temperature. Casting didn't
===quite work (sprue too thin, sand too wet) but I'm learning
===from my mistakes.
===
===I'm thinking of casting sculptures and parts for a Gingery
===Lathe. What is the interest out there for rough castings for
===such a lathe? I've built the foundry a bit bigger than the
===charcoal foundry, so I can make a longer or thicker bed...
===
===The other thing is the resulting cast seemed a bit soft...
===I've looked through the archives and heat treating the cast
===seems like a bit of a pain. Would a longer sprue make the
===cast denser/harder? Or is it just the lawn chair aluminum
===that's not too great for this?
===
===Thanks,
===Tom.
===http://www.TomEberhard.com



================================================== =


This is worth repeating for benefit of all newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

Tom,
Cool! I'm just in the process of rounding up the stuff for my foundry.
I'm hoping to start building it this winter, but now that I am back in
school and working full time AND trying to spend quality time with the
family, the foundry might be wishful thinking right now.

I want to cast small scale engine blocks for some military models that
I am building.

Mike

Thanks for the replies... some more questions:

Your cheapest bet for good casting material is to use sand-cast
aluminum scrap such as cylinder heads, transmission housings,
differential housings, etc. of OLDER cars where these were indeed
sand-cast.

What's a good source for this kind of Al? A neighboring garage
is willing to let me take the occasional Al wheel, are those any
good?

What are degassing tablets?

Thanks Roy for the info, nice site too! The shaper's very
impressive. What kind of lathe and milling machine do you
have?

Mike, if you're near Boston we can have a casting party
to get you started with casting while you build the foundry...
I won't do your pattern and sandwork, but will gladly pour. :-)

Tom.
http://www.TomEberhard.com

Thanks for the replies... some more questions:

Your cheapest bet for good casting material is to use sand-cast
aluminum scrap such as cylinder heads, transmission housings,
differential housings, etc. of OLDER cars where these were indeed
sand-cast.

What's a good source for this kind of Al? A neighboring garage
is willing to let me take the occasional Al wheel, are those any
good?

What are degassing tablets?

Thanks Roy for the info, nice site too! The shaper's very
impressive. What kind of lathe and milling machine do you
have?

Mike, if you're near Boston we can have a casting party
to get you started with casting while you build the foundry...
I won't do your pattern and sandwork, but will gladly pour. :-)

Tom.
http://www.TomEberhard.com
I have two suggestions.
1. Join a casting group like castinghobby and read all the back posts:
http://groups.yahoo.com/group/castinghobby/
2. Add yourself to the map of members:
http://www.frappr.com/castinghobby
The latter will help you find someone in your area with similar interests, if
there are any. There is no substitute for hands on experience with a willing
friend!
The map is open to everyone, and you can put in a "shout out" with text and a
photo to tell potential friends what you like.
There is a wealth of info on the group!


Ron Thompson
On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA

http://www.plansandprojects.com
My hobby pages are he
http://www.plansandprojects.com/My%20Machines/

Severe stupidity is self correcting, but mild stupidity is rampant in the land.
-Ron Thompson

Tom
Aluminum wheels from vehicles are generally very good to use for sand
casting. Another super item is pistons. I keep any and all pistons
separate from all other aluminum pieces.......Its some great stuff/

Degassing tablets are used to degas or allow hydrogen gas that builds
up in a crucinble of molten aluminum to dissipate and escape out of
the molten metal. This hydrogen sulphide smells like rotten eggs, and
makes a casting very porous. Once you cast something and start to
mahcine it, and you start to smell what appears to resemble rotten
eggs, what your encountering is a porouos casting with hydrogen
suplhide gas entrained in it. YOu can use regular swimming pool
chlorine tablets, ground up into a poweder or buy those one dose
packets of powder used for same purpose to save on having to pulverize
it, and add it to the mix at the rate of approx 1 tablespoon of the
material to 1 quart of crucible size or roughtly 4# of alumin. Its
added shortly after the metal has melted, and its best to add it
directly in to the bottom of the melt, by way of a tube with the
powder wrapped up in a piece of aluminum foil.....Resist all
temptations to stir your melt......it induces more air which also
induces more junk you do not want.......afterall your melting
aluminum, not making soup ;-) You can but actual degassing tablets
but they are pretty pricey, and the swimming pool tablets crushed up
work just as fine.

I fyour using a steel pipe cruicble or any any items that are made of
common carbon steel or any metal its best to coat them with a
refractory wash to further reduce contamination. You can use slip for
this coating if no actual refractory wash is available. Just thin it
out and apply it with a brush, allow to dry naaturally or place near
or over exhaust of furnace to accelerate its drying. It will harden up
and make a coatiing to keep contact of steel or metal from molten alum
to a minimum. It usually needs to be replaced after each melt or so,
so its not considered a permanent method, but in a back yard foundry
every little bit helps.

On 23 Nov 2005 14:21:48 -0800, "Tom" wrote:

===Thanks for the replies... some more questions:
===
=== Your cheapest bet for good casting material is to use sand-cast
=== aluminum scrap such as cylinder heads, transmission housings,
=== differential housings, etc. of OLDER cars where these were indeed
=== sand-cast.
===
===What's a good source for this kind of Al? A neighboring garage
===is willing to let me take the occasional Al wheel, are those any
===good?
===
===What are degassing tablets?
===
===Thanks Roy for the info, nice site too! The shaper's very
===impressive. What kind of lathe and milling machine do you
===have?
===
===Mike, if you're near Boston we can have a casting party
===to get you started with casting while you build the foundry...
===I won't do your pattern and sandwork, but will gladly pour. :-)
===
===Tom.
===http://www.TomEberhard.com



================================================== =


This is worth repeating for benefit of all newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

Roy,

Good info!

Just a caveat regarding aluminum wheel rims:

Most of them ARE cast and make good raw casting material.

However, a few are machined from rolled or forged blanks, and these are
less suitable.

Mercedes Benz rims are forged, I believe.

As to the earlier query where to find cast alu auto stuff: try auto
scrap yards. Also auto repair shops specializing in cylinder head or
transmission repair work.

Remember to only pay the scrap metal value for the items!

Regards,

Wolfgang

I got an email about Al wheels that was not posted here, thought I'd
pass it along:

+ Be careful using Al wheels, some have magnesium in them,
+ and can flare up in your face. Try getting Al piston from any type
+ of engine. Lawnmower engines are also good Al material to use.

Unfortunately the author did not mention how to differentiate between
the two. One one of the Al pans that I've scrounged up, it says
"Al Si 12 (Cu)" on it, I'm guessing 12% Silicon and a little bit of
Copper.
I'll avoid wheels that ever say Mg on it (Magnesium). Mn is Manganese,
but I don't think that's commonly added.

Tom.
http://www.TomEberhard.com