Just bought an electric hot water tank (for use as a biodiesel reactor).
Since the magnesium sacrificial anode would interfere with the reaction, I
removed it and then began wondering if there are any interesting
"experiments" to be performed with it. I expect such experiments would
relate mainly to combustion but there may be others. Anyone have any
suggestions?

Laurie Forbes

Hmm...

Can alloy with aluminum, if you want.

Pyrotechincal persuits:
- Burn plain
- Grind into filings/powder
- Mix half and half with aluminum ("magnalium", beware of flaring while
melting!) to make a brittle, easy to crush alloy

Finely divided material (either by mixing with aluminum and crushing or
using plain) can be used for thermite, for example.
Iron: 3 parts (by weight) Fe2O3 (red rust, heat to redness to dehydrate for
the best performance), 1 part Mg/Al
Lead: 10 parts PbO (yellow lead), 1 part Mg
Copper: 8 parts Cu2O (red cuprous oxide), 1 part Mg
Fast-burning thermites:
5 parts PbO2 (gray lead dioxide) to 1 Mg
3 parts CuO (black cupric oxide) to 1 Mg
(Caution, will detonate on impact!)

Other random stuff... get out your Periodic Table and find oxides you have
on hand!

Thermite type reactions also work with alkali metals, take lye for instance:
2Mg + 2NaOH = 2Na + 2MgO + H2 (though sodium is highly reactive, MgO is more
stable, so it proceeds). Rumor has it you can get silicon semimetal the
same way (i.e. SiO2 + 2Mg = Si + 2MgO), but it needs something like sulfur
added to speed it along; the difference in reactivity between magnesium,
aluminum and silicon isn't much.

Mechanical uses... heck, wherever you need something lightweight, if it's
not too pitted.

Oh- you can always make a battery. Magnesium has a potential of -2.356V
against hydrogen (-2.696V against copper). Hence its original use as
galvanic protection ;-)

Tim

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

"Laurie Forbes" wrote in message
news:xpbme.22418$wr.7748@clgrps12...
Just bought an electric hot water tank (for use as a biodiesel reactor).
Since the magnesium sacrificial anode would interfere with the reaction, I
removed it and then began wondering if there are any interesting
"experiments" to be performed with it. I expect such experiments would
relate mainly to combustion but there may be others. Anyone have any
suggestions?

Laurie Forbes

Tim Williams wrote:
Hmm...

Can alloy with aluminum, if you want.

Pyrotechincal persuits:
- Burn plain
- Grind into filings/powder
- Mix half and half with aluminum ("magnalium", beware of flaring while
melting!) to make a brittle, easy to crush alloy

Finely divided material (either by mixing with aluminum and crushing or
using plain) can be used for thermite, for example.
Iron: 3 parts (by weight) Fe2O3 (red rust, heat to redness to dehydrate for

You want the black iron oxide. Heat rust until it turns black, or burn some steel wool.

the best performance), 1 part Mg/Al
Lead: 10 parts PbO (yellow lead), 1 part Mg
Copper: 8 parts Cu2O (red cuprous oxide), 1 part Mg

these lead based mixtures sounds scary. You don't want to breathe a cloud of lead smoke.

Fast-burning thermites:
5 parts PbO2 (gray lead dioxide) to 1 Mg
3 parts CuO (black cupric oxide) to 1 Mg
(Caution, will detonate on impact!)

Other random stuff... get out your Periodic Table and find oxides you have
on hand!

Thermite type reactions also work with alkali metals, take lye for instance:
2Mg + 2NaOH = 2Na + 2MgO + H2 (though sodium is highly reactive, MgO is more
stable, so it proceeds). Rumor has it you can get silicon semimetal the
same way (i.e. SiO2 + 2Mg = Si + 2MgO), but it needs something like sulfur
added to speed it along; the difference in reactivity between magnesium,
aluminum and silicon isn't much.

Mechanical uses... heck, wherever you need something lightweight, if it's
not too pitted.

Oh- you can always make a battery. Magnesium has a potential of -2.356V
against hydrogen (-2.696V against copper). Hence its original use as
galvanic protection ;-)

Tim

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

"Laurie Forbes" wrote in message
news:xpbme.22418$wr.7748@clgrps12...
Just bought an electric hot water tank (for use as a biodiesel reactor).
Since the magnesium sacrificial anode would interfere with the reaction, I
removed it and then began wondering if there are any interesting
"experiments" to be performed with it. I expect such experiments would
relate mainly to combustion but there may be others. Anyone have any
suggestions?

Laurie Forbes

"Cydrome Leader" wrote in message
...
You want the black iron oxide. Heat rust until it turns black,
or burn some steel wool.

You need to heat Fe2O3 with a reducing agent, such as some organic matter or
charcoal, to get it. Burnt wool will work.

Fe3O4 vs. Fe2O3 is a very mild difference but the latter has more heat,
having more oxygen. I suppose it depends on what you want to do.

Fe2O3 + Mg:
http://www.abymc.com/Video/Thermite.avi

these lead based mixtures sounds scary. You don't want to breathe a
cloud of lead smoke.

Yes, definetly an outdoor mixture.

Tim

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

Thank you Tim for the interesting response - a lot of things to try. One
has me puzzled however - with the 2Mg + 2NaOH = 2Na + 2MgO + H2 reaction, is
it done in aqueous solution and, if so, would the Na not simply react with
the water to form more NaOH (& H2)?

One other question - could an end of the Mg rod (about 1/2" dia) be ignited
similarly to magnesium ribbon? Maybe an arc welder could be used to light
it.

Laurie Forbes


"Tim Williams" wrote in message
...
Hmm...

Can alloy with aluminum, if you want.

Pyrotechincal persuits:
- Burn plain
- Grind into filings/powder
- Mix half and half with aluminum ("magnalium", beware of flaring while
melting!) to make a brittle, easy to crush alloy

Finely divided material (either by mixing with aluminum and crushing or
using plain) can be used for thermite, for example.
Iron: 3 parts (by weight) Fe2O3 (red rust, heat to redness to dehydrate
for
the best performance), 1 part Mg/Al
Lead: 10 parts PbO (yellow lead), 1 part Mg
Copper: 8 parts Cu2O (red cuprous oxide), 1 part Mg
Fast-burning thermites:
5 parts PbO2 (gray lead dioxide) to 1 Mg
3 parts CuO (black cupric oxide) to 1 Mg
(Caution, will detonate on impact!)

Other random stuff... get out your Periodic Table and find oxides you have
on hand!

Thermite type reactions also work with alkali metals, take lye for
instance:
2Mg + 2NaOH = 2Na + 2MgO + H2 (though sodium is highly reactive, MgO is
more
stable, so it proceeds). Rumor has it you can get silicon semimetal the
same way (i.e. SiO2 + 2Mg = Si + 2MgO), but it needs something like sulfur
added to speed it along; the difference in reactivity between magnesium,
aluminum and silicon isn't much.

Mechanical uses... heck, wherever you need something lightweight, if it's
not too pitted.

Oh- you can always make a battery. Magnesium has a potential of -2.356V
against hydrogen (-2.696V against copper). Hence its original use as
galvanic protection ;-)

Tim

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

"Laurie Forbes" wrote in message
news:xpbme.22418$wr.7748@clgrps12...
Just bought an electric hot water tank (for use as a biodiesel reactor).
Since the magnesium sacrificial anode would interfere with the reaction,
I
removed it and then began wondering if there are any interesting
"experiments" to be performed with it. I expect such experiments would
relate mainly to combustion but there may be others. Anyone have any
suggestions?

Laurie Forbes

"Laurie Forbes" wrote in message
news:gDtme.32277$tt5.31518@edtnps90...
One has me puzzled however - with the 2Mg + 2NaOH = 2Na + 2MgO + H2
reaction, is it done in aqueous solution and, if so, would the Na
not simply react with the water to form more NaOH (& H2)?

Indeed it would. In fact the Mg would just react straightaway, as it does
anyways, Mg + 2H2O = Mg(OH)2 + H2. It doesn't proceed very fast.

However, a mixture of Mg turnings and lye will ignite quite easily and give
off orange flames of sodium vapor (since it burns that hot). Potassium also
works.

One other question - could an end of the Mg rod (about 1/2" dia) be
ignited similarly to magnesium ribbon? Maybe an arc welder could be
used to light it.

Possibly. My experience (with approx. 95% Mg, cast alloy) is the whole mass
must be pretty near ignition temperature to burn at all, otherwise it just
sinks the heat away. Mag of this purity also melts before it burns
appreciably.

Go visit Theodore Gray's website and check the related story under
magnesium. Then go read about the sodium party, because it's just too fun
to pass up. BG

Tim

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

"Tim Williams" wrote in message
...
"Laurie Forbes" wrote in message
news:gDtme.32277$tt5.31518@edtnps90...
One has me puzzled however - with the 2Mg + 2NaOH = 2Na + 2MgO + H2
reaction, is it done in aqueous solution and, if so, would the Na
not simply react with the water to form more NaOH (& H2)?

Indeed it would. In fact the Mg would just react straightaway, as it does
anyways, Mg + 2H2O = Mg(OH)2 + H2. It doesn't proceed very fast.

However, a mixture of Mg turnings and lye will ignite quite easily and
give
off orange flames of sodium vapor (since it burns that hot). Potassium
also
works.

OK - sounds worth trying.

Go visit Theodore Gray's website and check the related story under
magnesium. Then go read about the sodium party, because it's just too fun
to pass up. BG

I did that and it made me wish I had know someone like that when I was a kid
as I had a strong childhood interest in chemistry but with practically
no-one to share it.

Laurie Forbes

"Laurie Forbes" wrote in message
news:gDtme.32277$tt5.31518@edtnps90...

One other question - could an end of the Mg rod (about 1/2" dia) be
ignited
similarly to magnesium ribbon? Maybe an arc welder could be used to light
it.

A friend of mine had a disk of magnesium about 2 inches in diameter and 3/8
thick. He struck arcs on it, heated it with a propane torch, and got a few
sputters and spurts but no ignition.

He was having a party one fine weekend and set the disk on the gas burner of
the kitchen range. We were standing around drinking beer and observing this
chunk of metal. I saw that occasionally there was a spark or two where the
arcs had struck and I wondered if applying a little oxygen would help.

I pulled the guts out of a Bic pen and used this as a blow tube. It
appeared to increase the sputtering so I kept at it and then the chunk lit
off. The light the stuff gave off was intense as was the copious amounts of
smoke.

I picket up a set of tongs to grab the disk and toss it outside, but the
stuff just melted and I had to use a spoon to recover the burning glob and
tossed it in to the garden.

It had burned a hole clear through the aluminum burner.

If you insist on playing with this, do it outside, stay upwind, and do it
over a bucket of sand.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

The rec.pyrotechnics group will have many suggestions for this rod.

Doug