Methanol, purity, Zinc, and corrosion
Mike Smith
pure enough, I went to the local Science Shop and bought a bottle
of 'pure' methanol. While is isn't reagent grade, it does state
that is is "Methanol, anhydrous,, acetone free" and is packed by
HUMCO Laboratory. I presume that it will not have any corrosion
inhibiters in it...
I also purchased a couple of Erlenmeyer flasks with black rubber
lab stoppers and a sheet of Zinc.
I now have one flask with the HUMCO methanol in it and a fresh
piece of Reynolds Wrap aluminum foil in it (cut under methanol).
I have another flask with the HUMCO methanol in it and a fresh
piece of Sheet Zinc in it (cut in air). (Zinc is a common casting
metal).
So far? Nothing has happenend. I'm now out about $58 for a
variety of stuff ($19 for a real nice 5 gal. race fuel bottle
$12 for 5 gal of methanol from a drum. Another $25 at the
Science Shop and a couple of bucks for aluminum foil). I've
put alot of money where John's mouth is, so now I have a couple
of questions:
Is Zinc a 'light metal'?
You state:
> Methanol will rapidly and completely turn light metals
> into white powder.
Which 'light metals' were you talking about? It is looking less and
less like Aluminum and Zinc ...
> I learned that lesson the hard way when using methanol as a racing fuel.
Was this methanol doctored in some way? Corrosion inhibiters? NITRO?
> If you want to see for yourself, go to the hardware store, buy a gallon,
> and chunk some aluminum foil into it.
I've done this. Nothing happened. I've tried it with methanol from
a racing car supply store. Nothing happened. I've tried it with
methanol from a science supply store. Nothing happened. I've tried
it with my lawn mower carb (which another person has assured me IS
aluminium on a Briggs & Stratton engine) and methanol from the hardware
store. Nothing happened.
I will continue with the present series of experiments (and may even add
copper, iron, and some other metals and try lacing with iodine and/or
salt) but this is straying ever farther from the expected composition
for the fuel and carberetor. (Iodine and salt in my fuel? YIKES!)
But John, what am I doing wrong? I'm not particularly interested in
funding too many more variations on this experiment, so please give
me enough facts to make some 'light metal' (preferably aluminum)
corrode in methanol. It would be nice if you spent some of your own
money first to make sure that the facts were right ...
I'll give it a couple of weeks more, but I'm beginning to doubt the
much talked about 'corrosive' nature of methanol.
Oh yes, I almost forgot: The methanol at the race shop was shipped
from Ashland Chemical in Steel 55 gallon drums. Looks like there is
some kind of simple way to assure that is doesn't corrode steel ...
and the plastic bottle from the Science Shop seems to have no
problems either. Somehow I suspect that finding suitable materials
to handle methanol will not require stainless steels or exotic
flourochloroplastics.
--
E. Michael Smith e...@apple.COM
'Whatever you can do, or dream you can, begin it. Boldness has
genius, power and magic in it.' - Goethe
I am not responsible nor is anyone else. Everything is disclaimed.
John G. De Armond
>But John, what am I doing wrong? I'm not particularly interested in
>funding too many more variations on this experiment, so please give
>me enough facts to make some 'light metal' (preferably aluminum)
>corrode in methanol. It would be nice if you spent some of your own
>money first to make sure that the facts were right ...
I really cannot diagnose your experimental or materials problems from
long distance. You'll have to do that. I do, however, wonder if you
will be ready to go in record refuting a rather vast body of experience
regarding the corrosive effects of methanol on light alloys (generally
defined as aluminum or aluminum/magnesium alloys with or without
silicone.) based on your single, rather uncontrolled experiment? If
not, the you might want to be a bit careful about generalizing based
on a single event.
As to spending my money, I already have - in the form of a totally trashed
racing chain saw and severe damage to light alloy motorcycle carbs. Most
race mechanics, especially those involved in speedway, midget, formula,
or top alcohol drag racing will have a horror story or 2 regarding careless
choices of materials and alcohol. I've never tried aluminum foil and
I have no idea of the composition of same. But that's what's so nice about
this net - I can learn about corrosion (or lack thereof) of aluminum foil
at your expense and you can learn about the corrosive effects of methanol
in other contexts from me and others at our expense - if you listen.
To make your experiment complete, you really should experiment with
a range of temperature, moisture, and contaminations typical of
an automotive environment, and with a range of alloy compositions.
You could even be published, perhaps.
>Oh yes, I almost forgot: The methanol at the race shop was shipped
>from Ashland Chemical in Steel 55 gallon drums. Looks like there is
>some kind of simple way to assure that is doesn't corrode steel ...
>and the plastic bottle from the Science Shop seems to have no
>problems either. Somehow I suspect that finding suitable materials
>to handle methanol will not require stainless steels or exotic
>flourochloroplastics.
Are you again extrapolating from the rather benign conditions a 55 gal
drum experiences to the general case of automotive fuel systems? I
hope not. On the other hand, as I understand it (and I'll let net.chemists
help me get the terminology correct), the corrosive property of alcohol
toward light metal stems from the OH ion on the molecule. Hydroxyl ions
have never to my knowledge been reported to be corrosive to ferrous
metals. I do know that ordinary carbon steel is the ASME-approved
material for handling strong bases such as NaOH.
John
--
John De Armond, WD4OQC | We can no more blame our loss of freedom on congress
Radiation Systems, Inc. | than we can prostitution on pimps. Both simply
Atlanta, Ga | provide broker services for their customers.
{emory,uunet}!rsiatl!jgd| - Dr. W Williams | **I am the NRA**
Chris Luchini
rapidly as "high strength" Al alloys that contain magnesium (?).
Mike Smith
>e...@Apple.COM (Mike Smith) writes:
>
>>But John, what am I doing wrong? I'm not particularly interested in
>>funding too many more variations on this experiment, so please give
>>me enough facts to make some 'light metal' (preferably aluminum)
>>corrode in methanol.
>I really cannot diagnose your experimental or materials problems from
>long distance. You'll have to do that. I do, however, wonder if you
>will be ready to go in record refuting a rather vast body of experience
>regarding the corrosive effects of methanol on light alloys (generally
>defined as aluminum or aluminum/magnesium alloys with or without
>silicone.) based on your single, rather uncontrolled experiment? If
>not, the you might want to be a bit careful about generalizing based
>on a single event.
Whose 'vast body of experience'? Please post specifics and cite
the degree of control used in the evaluation.
Yes, I would like to go on record. My position is only that some
resonably available casting materials (plastics, zinc, aluminum)
can be found that do not cost a great deal and yet suffer no
significant corrosion effects from alcohols. I think I've shown
that there does exist some 'safe' combination of materials and fuels.
I don't need to prove that there is never any corrosion, only that
there are reasonably simple cases where there is no corrosion.
As to the degree of control: I've now got four different tests running
(not a 'single' experiment). Two of them in rather traditional lab
ware with typical chemical house materials, one in a cheap plastic tub
with typical racing shop methanol, and one being a real world test
in a production engine with commercial methanol. This involves a
range of test materials and environments, some controlled for temperature
and humidity and others subjected to the typical climate variations
in California. Are you perhaps suggesting that typical lab technique
and/or real world trials of a fuel in a real engine are bad technique?
>As to spending my money, I already have - in the form of a totally trashed
>racing chain saw and severe damage to light alloy motorcycle carbs. Most
Hmmm, what's a 'racing chain saw'? Sounds like an interesting event,
but where do you sit? :-)
I really cannot diagnose your mechanical or materials problems from
long distance. You'll have to do that. I do, however, wonder if you
will be ready to go on record refuting a rather specific body of
experimental evidence regarding the corrosive effects of methanol
on aluminum and zinc based on your individual, rather uncontrolled,
anecdotal experience? If not, the you might want to be a bit careful
about generalizing based on a single event.
>To make your experiment complete, you really should experiment with
>a range of temperature, moisture, and contaminations typical of
>an automotive environment, and with a range of alloy compositions.
I have. My lawn mower is still doing just fine. It has been run
in the heat and cold. In wet and dry. With anhydrous fuel and with
water added to the fuel (wanted to see what would happen...). The
gas tank is a different metal from the carb. The carb has some
plastic parts in it and the head, piston, valves, etc. are all
different alloys from the carb, fuel tank (and fuel tank cap). While
it isn't exactly the same as any particular automobile, it is a
close enough model. All I really need to show is that some readily
available cheap casting material is available that is suitable for
making methanol carbs. This is an existance proof.
>>Oh yes, I almost forgot: The methanol at the race shop was shipped
>>from Ashland Chemical in Steel 55 gallon drums. Looks like there is
>>some kind of simple way to assure that is doesn't corrode steel ...
>>and the plastic bottle from the Science Shop seems to have no
>>problems either. Somehow I suspect that finding suitable materials
>>to handle methanol will not require stainless steels or exotic
>>flourochloroplastics.
>Are you again extrapolating from the rather benign conditions a 55 gal
>drum experiences to the general case of automotive fuel systems? I
>hope not.
Why not? These rather 'benign conditions' include being stored in the
back of a large van and trucked back and forth to races (all the
road vibrations & etc. that a car or truck can hope for); being
parked for weeks on end in the heat of summer and cold of winter
(the fuel van is left outside in the sun); being exposed to wind
and rain as fuel is dispensed (it is pumped into containers by
hand from the open back of the truck on the lift gate) and generally
being given all the 'benign conditions' that a car gas tank can
expect to see. The only exception that I can think of is their
lifespan. I believe that they don't spend a decade in service
prior to disposal, though they are returned for re-use for some
extended lifespan. Then again, my cars gas tank doesn't have to
be rolled around on a hand truck or have people stand on it ...
>On the other hand, as I understand it (and I'll let net.chemists
>help me get the terminology correct), the corrosive property of alcohol
>toward light metal stems from the OH ion on the molecule. Hydroxyl ions
>have never to my knowledge been reported to be corrosive to ferrous
>metals. I do know that ordinary carbon steel is the ASME-approved
>material for handling strong bases such as NaOH.
I have dug out my organic chem book and will post a bit of the
chemistry of alcohols as time permits (and assuming that the
topic seems to be of interest to others). One interesting note:
it states that alcohols are somewhat less acidic than water.
Nowhere does it state anything about alcohol being 'corrosive'.
Can you cite a reference for the statement that alcohol is corrosive?
My experience agrees with what I've re-read in the text; that the
behaviour of alcohols is very much like that of water when it comes
to reactions with metals. I would expect that much or your corrosion
experiences would have been about the same if the material in use
had been water instead of alcohol. Some aluminum alloys will be
corroded by acidic water (as I've experience with tomato sauce left,
cold, too long in the pan...) and some plastics are damaged by
methanol. Many are not. So use the ones that aren't damaged.
Mike Smith
>I've never tried aluminum foil and
>I have no idea of the composition of same. But that's what's so nice about
>this net - I can learn about corrosion (or lack thereof) of aluminum foil
>at your expense and you can learn about the corrosive effects of methanol
>in other contexts from me and others at our expense - if you listen.
Here we have a statement of lack of knowledge 'I have no idea' and
'I can learn about'...'aluminum foil' from the same person who stated
with high confidence as an Authority Figure:
>Methanol will rapidly and completely turn light metals
>into white powder. I learned that lesson the hard way when using
>methanol as a racing fuel. If you want to see for yourself, go to
>the hardware store, buy a gallon, and chunk some aluminum foil into it.
^^^^^^^^^^^^^
Does this constitute an admission that the 'chunk some aluminum foil'
statement was wrong?
I know I said I would try to avoid debating tactics and stick to the
straight and narrow ... but I just couldn't resist one last cheap
shot ... please forgive me ... I'll do 20 Hail Mary's ... :-)
Jonathan Papai
j...@rsiatl.UUCP (John G. De Armond) writes:
x
xregarding the corrosive effects of methanol on light alloys (generally
xdefined as aluminum or aluminum/magnesium alloys with or without
xsilicone.) based on your single, rather uncontrolled experiment? ---
x ^
x --- I've never tried aluminum foil and
xI have no idea of the composition of same. But that's what's so nice about
xthis net - I can learn about corrosion (or lack thereof) of aluminum foil
xat your expense and you can learn about the corrosive effects of methanol
xin other contexts from me and others at our expense - if you listen.
Aluminum foil is pretty pure aluminum. Die cast engine parts
are typically 380 or 390 aluminum alloy with 7% and 17% Silicon (no e)
and some Copper and other elements. For the case of Aluminum, the
pure metal is a hell of a lot less susceptible to corrosive attack
than its alloys. You can buy cladded plate that has the aluminum
alloy plate with a layer of pure aluminum on its outside for corrosion
resistance.
Unfortunately, pure Aluminum does not die cast well, or corrosion
would be a lot less of a problem. Also, cladding engine parts would be
prohibitively expensive.
xTo make your experiment complete, you really should experiment with
xa range of temperature, moisture, and contaminations typical of
xan automotive environment, and with a range of alloy compositions.
xYou could even be published, perhaps. ^^^^^^^^^^^^^^^^^^
If you are looking for the appropriate alloys, find a disk
drive you don't need any more. The die cast aluminum parts in there
are probably similar to that used in engine components (cost $0.00).
x>Oh yes, I almost forgot: The methanol at the race shop was shipped
x>from Ashland Chemical in Steel 55 gallon drums. Looks like there is
x>some kind of simple way to assure that is doesn't corrode steel ...
x>and the plastic bottle from the Science Shop seems to have no
x>problems either. Somehow I suspect that finding suitable materials
x>to handle methanol will not require stainless steels or exotic
x>flourochloroplastics.
x
xAre you again extrapolating from the rather benign conditions a 55 gal
xdrum experiences to the general case of automotive fuel systems? I
xhope not. On the other hand, as I understand it (and I'll let net.chemists
xhelp me get the terminology correct), the corrosive property of alcohol
xtoward light metal stems from the OH ion on the molecule. Hydroxyl ions
xhave never to my knowledge been reported to be corrosive to ferrous
xmetals. I do know that ordinary carbon steel is the ASME-approved
xmaterial for handling strong bases such as NaOH.
I'll post on the corrosion of steel in alcohols and bases
tomorrow after some research, (reading, not experiments).
x
xJohn
x
x--
xJohn De Armond, WD4OQC | We can no more blame our loss of freedom on congress
xRadiation Systems, Inc. | than we can prostitution on pimps. Both simply
xAtlanta, Ga | provide broker services for their customers.
x{emory,uunet}!rsiatl!jgd| - Dr. W Williams | **I am the NRA**
J.P.
****************************************************************
Jon Papai * I think of this project as
Mater.Sci.&Eng * quite important, it is you
Ohio State Univ. * I take lightly.
Pa...@kcgl1.eng.ohio-state.edu * -James T. Kirk
****************************************************************
Dave Smith
such a good story that I'm always willing to listen) but methanol corrosion
has been cited by just about every report I've seen on methanol fueled
vehicles as a problem. Why not just go read the literature before futzing
around? You might have a better idea of where to start with your experiments.
--
David L. Smith
FPS Computing, San Diego
ucsd!celerity!dave or da...@fps.com
"14 inches is not enough" - The Rev. Mom
Mike Smith
>John G. DeArmond may be full of it (and I suspect he often is, but he tells
>such a good story that I'm always willing to listen) but methanol corrosion
>has been cited by just about every report I've seen on methanol fueled
>vehicles as a problem. Why not just go read the literature before futzing
>around? You might have a better idea of where to start with your experiments.
I like John. Sometimes his postings are a bit on the extreme side,
but he gets the juices going and is generally well founded in
technical issues. If there wasn't someone to 'stir the pot' there
wouldn't be much stew to share ...
I don't doubt that there is corrosion of some materials in some
solutions of methanol. (Several plastics do quickly decompose and
alcohol is polar enough that some reactions with metals should happen).
I'm aware that some corrosion effects need to be watched for and
have been seen at some times with some materials (and are
frequently cited in methanol use studies).
What I doubt is that it deserves to be called 'corrosive' and
is a show stopper for the use of methanol as motor fuel. It is
a semantic quibble, but calling a material 'corrosive' brings to
mind things like sulphuric acid and visions of bubbling decay of
material into a frothy mass. While 'corrosion' can happen with
things as ordinary as water and iron, yet that doesn't prevent
the use of iron water pipes. (I know, if it corrodes it IS
corrosive; but that is the denotative meaning; the connotations
are somewhat different and don't show up in the dictionary.)
The impetus to 'futz' came from John's statement that anyone
could chunk some foil in some methanol and watch the action.
This didn't agree with my experience, so I decided to test
his specific assertion. Nothing happened. I was actually
hoping that something would happen so I could watch some fizz...
I'll likely add some acid to a batch for just that reason :-)
Check the literature? I suppose I could, but it would take a
while for me (I'm not real near any Chem library and don't have
a card for Stanford or San Jose State libraries.) A decent look
would have involved a 2.5 hour plus drive (round trip) to Berkeley
through the area disrupted by the loss of some freeways in the quake.
It also wasn't needed to meet my goals. I wanted to test John's
statement (which would require a personal experiment) and wanted
to do something 'real' rather than just cite someone citing
someone else citing ... I wanted to gain experience with the
materials (as opposed to finding 'The Definitive Answer' by
lab research). Often there are things noticed in the actual
practice that are missing in the written descriptions.
An example would be John's experience with alloy carbs. I don't
doubt that they do decompose rapidly in methanol; I expect
that some alloys would. It is unlikely that lab analysis has
included a random selection of carb alloys and their fittings.
It just isn't clear cut enough for hard science. (Many companies
would consider the materials they use proprietary and not
something they wanted to publish. Finding out what the alloys
were could be quite an experiment just in itself.)
This has been a fun exercise in how the net reacts to real world
activity as opposed to the usual {opinion, reference, citation} stuff.
It is clear from the number of vehicles running on methanol that
whatever corrosion effects there are with methanol have been
dealt with; citation wars would only succeed in showing that some
stuff does corrode and that other stuff doesn't and that cars
should be made with the stuff that doesn't. Doing a real life
trial has added some spice to the interactions.
It has also taken up far more time with postings than I expected
(and more than I can afford). I'll need to post less for a while
as I catch up on work and family obligations
Mike Smith
>For the case of Aluminum, the
>pure metal is a hell of a lot less susceptible to corrosive attack
>than its alloys.
the castable ones?
> If you are looking for the appropriate alloys, find a disk
>drive you don't need any more. The die cast aluminum parts in there
>are probably similar to that used in engine components (cost $0.00).
I could do that, or I could just go to my car mechanic and ask for
some junk parts. I'll likely do both.
I've got enough invested in materials now that adding a couple of
more flasks isn't a big deal. It looks like methanol corrosion
may be becomming a 'hobby' for me, at the present rate of accumulation
of options to try :-)