How To Make a Smelter

On Sun, 01 Feb 2009 09:13:53 -0600, Charles Vincent
wrote:

Stealth Pilot wrote:
On Tue, 27 Jan 2009 16:47:51 -0500, "Morgans"
wrote:

"Stealth Pilot" wrote

hydrogen embrittlement was a big bogey man in home castings but it is
easily understood and conquered.
OK, I understand hydrogen embrittlement is a "bad thing" but my question
is, where does it come from, start, or what do you do to prevent it from
happening in the first place.

I'm not an industrial chemist. this comes from watching what happens
in my castings and reading some of the references mentioned.


What you are describing is not Hydrogen Embrittlement. Hydrogen
Embrittlement is usually more of an issue for high carbon steels I
believe, though it effects aluminum as well. You can find information
on it under the heading of stress corrosion cracking and it is more of
an environmental issue than casting, as it is a problem for forgings and
weldments as well. It is the mechanism of failure I am pretty sure for
the old VW cases, as magnesium alloys are very susceptable to SCC.

Your description of the problem of the casting problem though is spot
on, if misnamed. Here is a good link on this and other alumminum
casting issues:

http://www.keytometals.com/Article83.htm

Charles

not a bad article.
as long as we understand what each other means the semantics isnt too
much of a problem.

hydrogen bubbles through a casting make it more brittle. they
significantly reduce the impact strength which is useful when you want
to smash it up for a retry at a melt. both I and a retired mechanical
engineer I know refer to this as hydrogen embrittlement (of the
casting) if industry has diverged off and use the term in a more
specialised manner good on 'em.

a hydrogen bubbled casting is seldom porous though.it is porous in the
sense that it has voids through it but they arent continuous. if it is
cup shaped you can fill one with water and it wont leak.
as long as we understand what we intend by the words then a little
error in semantics here or there is of no importance.

what I'm describing should be spot on because I'm describing exactly
what I've done. ...in my driveway.

my casting rejection rate would be about 1 in 20, if that.
Stealth Pilot

On Sun, 1 Feb 2009 12:13:59 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:


"Charles Vincent" wrote in message
. ..
Stealth Pilot wrote:
On Tue, 27 Jan 2009 16:47:51 -0500, "Morgans"
wrote:

"Stealth Pilot" wrote

hydrogen embrittlement was a big bogey man in home castings but it is
easily understood and conquered.
OK, I understand hydrogen embrittlement is a "bad thing" but my
question is, where does it come from, start, or what do you do to
prevent it from happening in the first place.

I'm not an industrial chemist. this comes from watching what happens
in my castings and reading some of the references mentioned.


What you are describing is not Hydrogen Embrittlement. Hydrogen
Embrittlement is usually more of an issue for high carbon steels I
believe, though it effects aluminum as well. You can find information on
it under the heading of stress corrosion cracking and it is more of an
environmental issue than casting, as it is a problem for forgings and
weldments as well. It is the mechanism of failure I am pretty sure for
the old VW cases, as magnesium alloys are very susceptable to SCC.

Your description of the problem of the casting problem though is spot on,
if misnamed. Here is a good link on this and other alumminum casting
issues:

http://www.keytometals.com/Article83.htm

Charles

Actually it highlights his misunderstanding of the process. In an effort to
look like he knows something about casting, he began searching the internet
and found reams of confusing material discussing hydrogen embrittlement, and
confused it with hydrogen absorption.

the references I use are aspin and ammin.
I occasionally search the net to see if anyone has a technique that is
better than I'm using but so far they confirm that my teacher was a
master of the art.

Nice link, by the way, it at least begins to discuss the difficulties of
pouring quality molten aluminum, especially in low volumes if you read
between the lines.

Saying you are going to pour a quality casting from melting old pistons, in
a steel pot, with a propane yard burner - is much like saying you are going
to grind you own crankshaft with a modified wood lathe and a hand grinder.

what baloney.
I use salamander or gold refining crucibles.
I use a waste oil burner of the "major type S" pattern.
in fact when a casting is larger than my crucible can handle I offload
the work to a commercial foundry. they use waterglass and resin
moulding techniques normally but also use greensand.
their greensand techniques vary from mine in the use of machine aids,
other than that we talk and do the same things.

you are so full of it your eyes are brown.
Stealth Pilot

"Stealth Pilot" wrote in message
...
On Sun, 01 Feb 2009 09:13:53 -0600, Charles Vincent
wrote:

Stealth Pilot wrote:
On Tue, 27 Jan 2009 16:47:51 -0500, "Morgans"
wrote:

"Stealth Pilot" wrote

hydrogen embrittlement was a big bogey man in home castings but it is
easily understood and conquered.
OK, I understand hydrogen embrittlement is a "bad thing" but my
question
is, where does it come from, start, or what do you do to prevent it
from
happening in the first place.

I'm not an industrial chemist. this comes from watching what happens
in my castings and reading some of the references mentioned.


What you are describing is not Hydrogen Embrittlement. Hydrogen
Embrittlement is usually more of an issue for high carbon steels I
believe, though it effects aluminum as well. You can find information
on it under the heading of stress corrosion cracking and it is more of
an environmental issue than casting, as it is a problem for forgings and
weldments as well. It is the mechanism of failure I am pretty sure for
the old VW cases, as magnesium alloys are very susceptable to SCC.

Your description of the problem of the casting problem though is spot
on, if misnamed. Here is a good link on this and other alumminum
casting issues:

http://www.keytometals.com/Article83.htm

Charles

not a bad article.
as long as we understand what each other means the semantics isnt too
much of a problem.

hydrogen bubbles through a casting make it more brittle. they
significantly reduce the impact strength which is useful when you want
to smash it up for a retry at a melt. both I and a retired mechanical
engineer I know refer to this as hydrogen embrittlement (of the
casting) if industry has diverged off and use the term in a more
specialised manner good on 'em.

Only in your hemisphere.


a hydrogen bubbled casting is seldom porous though.it is porous in the
sense that it has voids through it but they arent continuous. if it is
cup shaped you can fill one with water and it wont leak.
as long as we understand what we intend by the words then a little
error in semantics here or there is of no importance.

Then why some people impregnate castings to insure they are leak free.


what I'm describing should be spot on because I'm describing exactly
what I've done. ...in my driveway.

my casting rejection rate would be about 1 in 20, if that.
Stealth Pilot


And with all that experience, I'm sure you have plenty of photos, not.

"Stealth Pilot" wrote in message
news
On Sun, 1 Feb 2009 12:13:59 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:


"Charles Vincent" wrote in message
.. .
Stealth Pilot wrote:
On Tue, 27 Jan 2009 16:47:51 -0500, "Morgans"
wrote:

"Stealth Pilot" wrote

hydrogen embrittlement was a big bogey man in home castings but it is
easily understood and conquered.
OK, I understand hydrogen embrittlement is a "bad thing" but my
question is, where does it come from, start, or what do you do to
prevent it from happening in the first place.

I'm not an industrial chemist. this comes from watching what happens
in my castings and reading some of the references mentioned.


What you are describing is not Hydrogen Embrittlement. Hydrogen
Embrittlement is usually more of an issue for high carbon steels I
believe, though it effects aluminum as well. You can find information
on
it under the heading of stress corrosion cracking and it is more of an
environmental issue than casting, as it is a problem for forgings and
weldments as well. It is the mechanism of failure I am pretty sure for
the old VW cases, as magnesium alloys are very susceptable to SCC.

Your description of the problem of the casting problem though is spot
on,
if misnamed. Here is a good link on this and other alumminum casting
issues:

http://www.keytometals.com/Article83.htm

Charles

Actually it highlights his misunderstanding of the process. In an effort
to
look like he knows something about casting, he began searching the
internet
and found reams of confusing material discussing hydrogen embrittlement,
and
confused it with hydrogen absorption.

the references I use are aspin and ammin.
I occasionally search the net to see if anyone has a technique that is
better than I'm using but so far they confirm that my teacher was a
master of the art.

Nice link, by the way, it at least begins to discuss the difficulties of
pouring quality molten aluminum, especially in low volumes if you read
between the lines.

Saying you are going to pour a quality casting from melting old pistons,
in
a steel pot, with a propane yard burner - is much like saying you are
going
to grind you own crankshaft with a modified wood lathe and a hand grinder.

what baloney.
I use salamander or gold refining crucibles.
I use a waste oil burner of the "major type S" pattern.
in fact when a casting is larger than my crucible can handle I offload
the work to a commercial foundry. they use waterglass and resin
moulding techniques normally but also use greensand.
their greensand techniques vary from mine in the use of machine aids,
other than that we talk and do the same things.

you are so full of it your eyes are brown.
Stealth Pilot

Photos? Photos? Still waiting.

"Stealth Pilot" wrote

you are so full of it your eyes are brown.

Wrestling with Max is like wrestling with a pig.

You both get dirty, and the pig enjoys it.
--
Jim in NC

"Morgans" wrote in message
...

"Stealth Pilot" wrote

you are so full of it your eyes are brown.

Wrestling with Max is like wrestling with a pig.

You both get dirty, and the pig enjoys it.
--
Jim in NC


Not true. I have never attacked anyone that didn't throw the first punch,
including you.

On Feb 1, 9:49*am, Stealth Pilot
wrote:
...

I think that the same thing occurs with water believe it or not.
the fluid appears to dissociate into its component parts in the molten
aluminium.
the oxygen causes lots of oxide froth on the top of the crucible.
the hydrogen remains as a dissolved gas until the aluminium starts to
solidify whereupon it comes out of suspension as bubbles.
...


That sounds about right to me.

The solubility of a gas in molten metal increases with the temperature
of the gas. Aluminum, being a reactive metal, reacts readily with
the
oxygen creating dross and leaving the hydrogen in solution until
the metal cools whereupon the bubbles form.

Molten copper does not react readily with oxygen and oxygen bubbles
in cast copper are a problem when the melt is open to the air.

I've never heard of nitrogen bubbles in either metal so I assume the
solubility of nitrogen is very low for each.

On Feb 2, 3:18*am, Stealth Pilot
wrote:
...

hydrogen bubbles through a casting make it more brittle.

No.

they
significantly reduce the impact strength which is useful when you want
to smash it up for a retry at a melt.

Yes. They make the casting weaker, not more brittle.

Hydrogen embrittlement is also a potential problem with
electrolytic derusting and the the metal isn't even heated.

Hydrogen readily diffuses into cold steel. A bare steel
cylinder will not hold hydrogen for long under high pressure.
Hydrogen cylinders are plated on the inside with nickel.

...
a hydrogen bubbled casting is seldom porous though.it is porous in the
sense that it has voids through it but they arent continuous. if it is
cup shaped you can fill one with water and it wont leak.
as long as we understand what we intend by the words then a little
error in semantics here or there is of no importance.
...

Hydrogen bubbles in a casting won't do anything that other
gas bubbles in a casting do. The only reason you don't
get oxygen bubble in aluminum castings is because the
oxygen reacts with the aluminum. You can get oxygen
bubbles in copper castings, they do the same thing to
copper castings that hydrogen bubbles do to aluminum
castings but that is not called oxygen embrittlement
for the same reason that hydrogen bubbles in aluminum
castings are not called hydrogen embrittlement.

The right words convey the right idea. The wrong words
convey a wrong idea. Harsh words are unnecessary.

The whole point to a newsgroup is to exchange knowledge.

--

FF