Ok.. I've studied on this for a while.

Everybody says (exaggeration) you can't cast 6061 it has to be wrought. If
you try to cast it you get large crystals and poorly structured metal. One
article I read about casting 6061 seemed to indicate that rapid cooling of
sand type castings by blasting away the sand with water jets retarded
crystal growth. As near as I can tell wrought means formed by working or
under higher pressure. I'm sure somebody can provide a better definition in
context. I think forming under pressure might also retard crystal growth.

Now one of the pretty well known enemies of aluminum casting is the
formation of aluminum oxides during the melting process, and of course
oxides that have already formed. Rapid melting with a forced air foundry as
opposed to a naturally aspirated foundry seems to reduce this dramatically.
Surface area of the starting stock is also a factor so even with a forced
air furnace machined chips might not be a good candidate.

So why not use a steel die (permanent mold) with a cylinder shaped casting
sprue, and then when full place it on a press with a piston to apply
pressure. Then liquid cool it while still under pressure. If the process
proves possible its all achievable in the conditions of a home shop. Well a
home shop capable of making steel dies anyway. I would think pressure would
have to be regulated so that cooling contraction does not destroy the part.
The simplest shop press might not be upto the job as somebody would have to
stand there surround by steam pumping the jack. LOL.

The biggest issue I see is figuring out how to cap the vents when the die is
full so that you don't spray molten metal around the shop when you apply
pressure.

I don't even know if I should post this... Ah what the heck.

Flame on. (pun intended)

"Bob La Londe" wrote in message
...
Ok.. I've studied on this for a while.

Everybody says (exaggeration) you can't cast 6061 it has to be
wrought. If you try to cast it you get large crystals and poorly
structured metal. One article I read about casting 6061 seemed to
indicate that rapid cooling of sand type castings by blasting away
the sand with water jets retarded crystal growth. As near as I can
tell wrought means formed by working or under higher pressure. I'm
sure somebody can provide a better definition in context. I think
forming under pressure might also retard crystal growth.

Now one of the pretty well known enemies of aluminum casting is the
formation of aluminum oxides during the melting process, and of
course oxides that have already formed. Rapid melting with a forced
air foundry as opposed to a naturally aspirated foundry seems to
reduce this dramatically. Surface area of the starting stock is also
a factor so even with a forced air furnace machined chips might not
be a good candidate.

So why not use a steel die (permanent mold) with a cylinder shaped
casting sprue, and then when full place it on a press with a piston
to apply pressure. Then liquid cool it while still under pressure.
If the process proves possible its all achievable in the conditions
of a home shop. Well a home shop capable of making steel dies
anyway. I would think pressure would have to be regulated so that
cooling contraction does not destroy the part. The simplest shop
press might not be upto the job as somebody would have to stand
there surround by steam pumping the jack. LOL.

The biggest issue I see is figuring out how to cap the vents when
the die is full so that you don't spray molten metal around the shop
when you apply pressure.

I don't even know if I should post this... Ah what the heck.

Flame on. (pun intended)

https://www.kineticdiecasting.com/wh...e-casting.html

On Mon, 25 Mar 2019 09:45:53 -0700, "Bob La Londe"
wrote:

Ok.. I've studied on this for a while.

Everybody says (exaggeration) you can't cast 6061 it has to be wrought.

Uh, actually, I've posted the information here several times over the
years that you can cast 6061. It's not great, but it's good.

If
you try to cast it you get large crystals and poorly structured metal. One
article I read about casting 6061 seemed to indicate that rapid cooling of
sand type castings by blasting away the sand with water jets retarded
crystal growth. As near as I can tell wrought means formed by working or
under higher pressure. I'm sure somebody can provide a better definition in
context. I think forming under pressure might also retard crystal growth.

I've never heard that, but that's essentially what you're doing with
high-pressure die casting. The high pressure is to get better filling
of a mold, and to reduce pinholes and porosity.

But die casting usually involves rapid cooling, as well -- the fastest
you can achieve -- simply to improve production rates. Well-made die
casting do have pretty good grain structure but, even if you use
alloys made for diecasting, they're not exactly malleable.


Now one of the pretty well known enemies of aluminum casting is the
formation of aluminum oxides during the melting process, and of course
oxides that have already formed. Rapid melting with a forced air foundry as
opposed to a naturally aspirated foundry seems to reduce this dramatically.
Surface area of the starting stock is also a factor so even with a forced
air furnace machined chips might not be a good candidate.

So why not use a steel die (permanent mold) with a cylinder shaped casting
sprue, and then when full place it on a press with a piston to apply
pressure.

You've just described cold-chamber die casting. d8-)

Then liquid cool it while still under pressure. If the process
proves possible its all achievable in the conditions of a home shop. Well a
home shop capable of making steel dies anyway. I would think pressure would
have to be regulated so that cooling contraction does not destroy the part.
The simplest shop press might not be upto the job as somebody would have to
stand there surround by steam pumping the jack. LOL.

The biggest issue I see is figuring out how to cap the vents when the die is
full so that you don't spray molten metal around the shop when you apply
pressure.

A common issue with conventional die casting. They use chill vents,
sometimes made of beryllium copper, but more often machined right into
the steel die itself.


I don't even know if I should post this... Ah what the heck.

Flame on. (pun intended)

No flames. It''s an interesting thought. You should look into die
casting processes -- low pressure (BOP V8 of the early '60s, for
example); high pressure (most die casting) cold chamber (used more
often with magnesium, but also with aluminum in small-scale
operations); and hot-chamber (most aluminum die casting).

There are a number of issues to consider, not the least of which is
flash formation. With high pressure, it can be a big problem.

BTW, the thought of doing this at home gives me the chills. One of my
old co-workers at _American Machinist_ described his first visit to a
die-casting shop. "Now I know what it's like in hell," he said. d8-)

--
Ed Huntress

On 25/03/2019 16:45, Bob La Londe wrote:
Ok.. I've studied on this for a while.

Everybody says (exaggeration) you can't cast 6061 it has to be
wrought.Â*Â* If you try to cast it you get large crystals and poorly
structured metal.Â* One article I read about casting 6061 seemed to
indicate that rapid cooling of sand type castings by blasting away the
sand with water jets retarded crystal growth.Â* As near as I can tell
wrought means formed by working or under higher pressure.Â* I'm sure
somebody can provide a better definition in context.Â* I think forming
under pressure might also retard crystal growth.

Now one of the pretty well known enemies of aluminum casting is the
formation of aluminum oxides during the melting process, and of course
oxides that have already formed.Â* Rapid melting with a forced air
foundry as opposed to a naturally aspirated foundry seems to reduce
this dramatically. Surface area of the starting stock is also a factor
so even with a forced air furnace machined chips might not be a good
candidate.

So why not use a steel die (permanent mold) with a cylinder shaped
casting sprue, and then when full place it on a press with a piston to
apply pressure.Â* Then liquid cool it while still under pressure.Â* If
the process proves possible its all achievable in the conditions of a
home shop.Â* Well a home shop capable of making steel dies anyway.Â* I
would think pressure would have to be regulated so that cooling
contraction does not destroy the part. The simplest shop press might
not be upto the job as somebody would have to stand there surround by
steam pumping the jack. LOL.

The biggest issue I see is figuring out how to cap the vents when the
die is full so that you don't spray molten metal around the shop when
you apply pressure.

I don't even know if I should post this...Â* Ah what the heck.

Flame on.Â* (pun intended)



Maybe do some research into the use of chills in sand casting. IIRC the
old British Gardner Diesel engine had a sand cast aluminium crankcase
and used numerous chills in critical places to unsure rapid cooling of
critical areas for optimum strength. A mate works in engine design and
he has mentioned that aluminium cylinder heads are often done by
specialist casters as they have the knowledge to control the dendrite
formation in the castings especially for critical parts of the cylinder
head such as the head gasket face to get the maximum strength.