Author Topic: Methanol and metal comparability. (Read 14577 times)

dawesy · « **on:** January 21, 2015, 09:26:19 AM »

Thought I'd ask here as there's a wealth of knowledge.
I run a water/methanol injection system on my modified MR2 to aid inlet charge cooling and knock prevention.
I want to make a new tank for it and I was going to make one from aluminium but someone told me its a bad idea as methanol reacts with aluminium and can explode. Now I've seen a few tanks made from alloy used for just this purpose but after reading there seems to be some evidence to support this claim.
I decided to make one from stainless but it's obviously more expensive.
Is aluminium suitable for this application or are there any other materials I could use?
Thanks in advance.

John Rudd · « **Reply #1 on:** January 21, 2015, 09:35:50 AM »

When I worked at Centrica Storage gas terminal, we stored methanol in a mild steel tank some 13 metres high....good enough for them.....

dawesy · « **Reply #2 on:** January 21, 2015, 10:10:17 AM »

With the water mix it might get a bit rusty though.

Lew_Merrick_PE · « **Reply #3 on:** January 21, 2015, 10:30:12 AM »

Lee,

I am unaware of any problems with methanol/aluminum interactions. Aluminum parts (nearly all 7075 or 2024 alloys) used in medical devices are routinely ultrasonically cleaned in methanol before being washed off with water & detergent in hospitals (methanol being much less expensive or restricted than ethanol -- the preferred media). Methanol is also a significant ingredient in napalm -- which is "deployed" using (mostly) aluminum components.

The items referred to above would be (chromic or sulfuric) anodized -- which may be important. I have never run into issues regarding methanol, but I rarely work with such applications.

DavidA · « **Reply #4 on:** January 21, 2015, 11:02:13 AM »

I have Methanol stored in 1 gallon aluminium containers for use in my bio diesel process for years . I have never had a problem. The containers are only about 10 thou thick but so far no leakage.

Dave.

dawesy · « **Reply #5 on:** January 21, 2015, 11:18:38 AM »

Thanks for the replies guys.
Like I say I've seen a few alloy water/ meth tanks and never heard of any issues. Like I say it's not neat meth either.
Just like to be sure especially from an insurance point of view. Have a fair bit of cash invested and its correctly insured with all modifications declared. Would hate them to find some reason to not pay out if the worst happened.

Manxmodder · « **Reply #6 on:** January 21, 2015, 02:48:30 PM »

Lee, most of the grass track or speedway motorcycles I have had involvement with in the past have had ally tanks. I've never heard of such problems.....OZ.

vtsteam · « **Reply #7 on:** January 21, 2015, 03:48:11 PM »

And Cox Baby Bee .049 engines were the mainstay of the 1/2A control line models we built as kids. All had radial aluminum fuel tanks attached, and our fuel was methanol, castor oil and nitromethane mixes. Models, kept in basements, closets, and occasionally under the bed.

Not sayin' methanol won't explode in contact with aluminum, I just never heard of it personally.

tomrux · « **Reply #8 on:** January 22, 2015, 02:21:17 AM »

"Methanol is also a significant ingredient in napalm"

Ahhhh no in aint.

"napalm" is a contraction of Naptha and palm acid. 2 thickeners added to petroleum to produce napalm.
I don't know that Methanol would be energetic enough to be effective in this use.

on the note of the OP methanol is/was used in many racing motorcycles with alloy tanks, no adverse effects that I have ever seen.

Tom R

David Jupp · « **Reply #9 on:** January 22, 2015, 02:54:03 AM »

Page 120 of this reference suggests there can be some slow (pitting) corrosion
http://www.methanol.org/getattachment/05f122f1-c9d3-47d8-8c16-5a5d39717cbe/Methanol-Safe-Handling-Manual-Final---English.pdf.aspx

Routine monitoring is suggested as a way of managing, rather than saying Aluminium alloys should not be used.

The section regarding this is rather woolly - doesn't mention the conditions that might lead to corrosion with aqueous solutions; I'd interpret that as suggesting that corrosion is rare and perhaps influenced by other substances present.

You should be able to use a manual like this as a justification for you choice, as long as you plan some inspection/monitoring to check for corrosion.

Lew_Merrick_PE · « **Reply #10 on:** January 22, 2015, 10:23:49 AM »

Quote from: tomrux on January 22, 2015, 02:21:17 AM

"Methanol is also a significant ingredient in napalm"

Ahhhh no in aint.

"napalm" is a contraction of Naptha and palm acid. 2 thickeners added to petroleum to produce napalm.
I don't know that Methanol would be energetic enough to be effective in this use.

Methanol was also used to "thin" napalm for certain "deforestation activities" in Vietnam. Although I did not know it at the time, I worked on the dispense nozzles for that program. The program was "covered" under a USDA contract that, supposedly, was to aid in lighting "controlled back-fires" for fighting wildfires. I later saw the equipment loaded on C2 aircraft...

dawesy · « **Reply #11 on:** January 22, 2015, 01:03:16 PM »

Cool stuff guys. That's why I love it here.

That makes things cheaper as I have a sheet of alloy so just need some bar to make the neck from

bp · « **Reply #12 on:** January 22, 2015, 06:38:46 PM »

A friend of mine used to fly F1C model aeroplanes, which use methanol and oil, about 80 to 90% methanol and the rest castor oil. At one point he was using machined al. alloy tanks, probably 6061 T6 or one of the 2000 series. After a few flights he noticed a black sludge coming out of the tank when cleaning the models. He switched to Delrin..........
cheers
Bill

PekkaNF · « **Reply #13 on:** January 23, 2015, 02:24:49 AM »

Quote from: bp on January 22, 2015, 06:38:46 PM

A friend of mine used to fly F1C model aeroplanes, which use methanol and oil, about 80 to 90% methanol and the rest castor oil. At one point he was using machined al. alloy tanks, probably 6061 T6 or one of the 2000 series. After a few flights he noticed a black sludge coming out of the tank when cleaning the models. He switched to Delrin..........
cheers
Bill

That reminds me of some vaguely familiar guy's tossing out aluminium AN fittings if they were damaged or modified. He explained that anodised aluminium is very fine with nitro methane, but plain is a bad call. He mentioned sludge too.

Pekka

dawesy · « **Reply #14 on:** January 23, 2015, 04:13:34 AM »

Might make up a small test tank and fill with the mix and see what happens then

S. Heslop · « **Reply #15 on:** January 23, 2015, 05:48:03 AM »

Quote from: tomrux on January 22, 2015, 02:21:17 AM

"Methanol is also a significant ingredient in napalm"

Ahhhh no in aint.

"napalm" is a contraction of Naptha and palm acid. 2 thickeners added to petroleum to produce napalm.
I don't know that Methanol would be energetic enough to be effective in this use.

There wasn't any napthenic or palmitic acid in later compositions of napalm used by the Vietnam era.

David Jupp · « **Reply #16 on:** January 23, 2015, 10:02:40 AM »

Quote from: dawesy on January 23, 2015, 04:13:34 AM

Might make up a small test tank and fill with the mix and see what happens then

Much easier to just put some mix in a glass jar, then drop in an offcut of the proposed alloy.

To make monitoring of your finished tank easy - include a small test coupon of the construction material that you can lift out from time to time to examine closely.

PekkaNF · « **Reply #17 on:** January 23, 2015, 10:15:25 AM »

Yep. That is good old immersion test. It gives fast and repeatable results when there only a simple chemical resistance to be tested.

However experience has shown that automoive fuel system is whole lot more complex. Ref. "Sour gas" and abrasion results when simple NBR fuel hoses were proven fine on laboratory, but not in reality, when subjected then new fuel injection features: Fuel aeration due to tank return line, increased flow rate etc. induced problems.

I'm pretty sure that piece of clean aluminium would survive well on pure methanol on well controlled enviroment. I wonder what small exotic metal impurities, a little water on mix etc, would do?

Pekka

David Jupp · « **Reply #18 on:** January 23, 2015, 12:25:24 PM »

From the reference linked earlier;- Note that the OP wants a tank to hold Methanol/Water mix.

Pure anhydrous methanol is mildly corrosive to lead and aluminum alloys.....
Rate of attack on aluminum alloys is typically a slow pitting form of corrosion; however, it can be
accelerated to the point of compromising integrity of structural components if not
anticipated and monitored.

Methanol-water solutions can be corrosive to some non-ferrous alloys depending on
application and environmental circumstances. This caution applies to equipment built with
copper alloy, galvanized steel, titanium, aluminum alloy components....

dawesy · « **Reply #19 on:** January 23, 2015, 04:53:48 PM »

just had a good read. think i will put a sample in a glass jar and monitor.
it will be a month or so till i make the tank so ill keep the jar with the sample in and if it starts showing signs of degradation i can pull the tank for closer inspection.
there is a 30um filter before the pump which i check and clean periodically also i go through 5 ltrs of water\meth in a couple of months so i can check during top up.

efrench · « **Reply #20 on:** January 23, 2015, 08:37:10 PM »

How about epoxy painting the interior of the tank?

dawesy · « **Reply #21 on:** January 24, 2015, 03:19:38 AM »

Not a bad idea ;)

PekkaNF · « **Reply #22 on:** January 24, 2015, 07:06:47 AM »

If you find a good and stable "Fuel tank sealer" or such, please share your experience. Many of us would be greatly tnterested that one too.

Pekka

dawesy · « **Reply #23 on:** January 24, 2015, 09:41:03 AM »

Found this.
http://www.rust.co.uk/0003-slosh-ethanol-resistant-tank-seal-kit/p413135/
Ethanol resistant so should be ok for methanol too.

vtsteam · « **Reply #24 on:** January 24, 2015, 11:57:02 AM »

Would something like this be large enough?:

http://www.amazon.co.uk/gp/product/B005CB2YJ2

dawesy · « **Reply #25 on:** January 25, 2015, 08:07:48 AM »

Could be. I'd have to sit and work out the volume (maths is my Achilles heel

)
Needs to hold about 5ltrs. Also want 316l if it's stainless. Not sure on the grade of that. Very cheap though. ;)

vtsteam · « **Reply #26 on:** January 25, 2015, 10:05:37 AM »

Lee, I make it 3820 CC

dawesy · « **Reply #27 on:** January 25, 2015, 11:17:29 AM »

Cheers for that, saves me melting my brain later

Mmm could do with it a bit bigger really.

Will_D · « **Reply #28 on:** January 26, 2015, 04:34:19 PM »

Quote from the Wiki:

"One of the potential drawbacks of using high concentrations of methanol (and other alcohols, such as ethanol) in fuel is the corrosivity to some metals of methanol, particularly to aluminium. Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminum from corrosion:

6 CH3OH + Al2O3 → 2 Al(OCH3)3 + 3 H2O

The resulting methoxide salts are soluble in methanol, resulting in a clean aluminium surface, which is readily oxidized by dissolved oxygen. Also, the methanol can act as an oxidizer:

6 CH3OH + 2 Al → 2 Al(OCH3)3 + 3 H2

This reciprocal process effectively fuels corrosion until either the metal is eaten away or the concentration of CH3OH is negligible. Concerns with methanol's corrosivity have been addressed by using methanol-compatible materials, and fuel additives that serve as corrosion inhibitors."

Recall that its the oxide layer that protects the metal (just like the chromium oxide layer on stainless steel)

I also know also from first hand experience that tomato soup and its mould can eat through 1mm of aliminium saucepan in about a week

dawesy · « **Reply #29 on:** January 27, 2015, 04:11:14 AM »

I've used water injection for a while and yet to see any adverse effects. As its a fine mist it never really contacts the port walls and is burnt in the combustion process. The only area that I had doubts on was the storage vessel.
I'm using a plastic fuel can at the mo but it looks a bit bodged hence the fabrication of something a bit more permanent.
Good info though.

mattinker · « **Reply #30 on:** January 27, 2015, 11:48:34 AM »

Why not just fabricate a box around the plastic container? It would make it strong and look nice!

Regards, Matthew

dawesy · « **Reply #31 on:** January 27, 2015, 02:26:24 PM »

It doesn't really fit the space it's in :/.
I'll get a pic to show what I mean.

News:

Author Topic: Methanol and metal comparability. (Read 14577 times)