Cast Magnesium

[Joe C.]

Can anyone recommend a non abrasive process for renewing the finish of a cast magnesium fuel pump.
Pump is in excellent condition, only shows oxidation and grime.
Thanks in advance.

Joe

[Robert Z.]

Re: Cast Magnesium


Joe, try spraying liberal amounts of WD40 on the pump, letting it soak overnight and respray it and scrub it with a tooth brush. Should loosen the oxidation and grime and won't be too abrasive. Works well on cast aluminum parts as well. Bob

[Jeff S.]

Re: Cast Magnesium

Joe

You could try a cleaner with an alkaline formula and a mild pH (perhaps Clorox Bathroom Cleaner, etc). Don't use anything with muriatic acid, as it will likely blacken Mg.

[John D.]

Re: Cast Magnesium

Joe,I can remember years ago I put a magnesium FI disc in some strong chemicals and in a few seconds up poured green lethal smoke. So be careful as to what you use. Even household vinegar will eat holes in magnesium. Been there. My 63 fuel pump has a magnesium round bottom. As it should have by the way. Are you sure the entire pump is magnesium?
Mag wheel cleaner may be phospheric acid. Read the label. If you end up using phospheric use a lot of water to cut it.
In the olden days in Hot Rod someone mentioned a good trick was to use a certain toilet bowl cleaner (forget the name). Well I tried it on an intake an immediately the whole thing turned dark grey. Chemically burnt. JD

[Duke W.]

Re: Cast Magnesium

A household cleaning product I have called Lime-Away smells exactly like the bottle of PPG Alumiprep that I have, which is phosphoric acid based.

An Alumiprep wash is part of the process for painting aluminum (followed by the Alodine conversion coating).

In fact I have more Alumiprep that I will probably use in my lifetime, so I am diluting it and adding it to the Lime-Away spray bottle.

Some time ago I did some research on how to keep magnesium castings looking good for a buddy who has a GT-40 Mark V. I contacted some materials specialists in the aerospace industry since aerospace uses a lot of magnesium castings. I figured they must use some kind of coating to protect the magnesium castings from corrosion, but the answer was no! They are bare.

Magnesium, like aluminum, quickly develops a surface oxide, which actually protects the metal (but looks like hell), but cosmetic appearance is not critical to these castings as it is for a car wheel.

So I was not able to come up with any ideas for a protective coating, and I didn't ask about cleaning old magnesium.

I recall helping my buddy polish the wheel lips to a near mirror like finish and a month later they looked like mouse fur!

Duke

[Clem Z.]

Re: Cast Magnesium

plain water will attack magnesium as i had real mag wheels on some of my mid years and they turned dark just from getting wet. i would say clear coat after cleaning if you want it to stay looking new.

[Cecil L.]

Re: Cast Magnesium

Some products from my other hobby:

http://www.aircraftspruce.com/catalog/cspages/magtreatkit.php

http://www.aircraftspruce.com/catalog/cspages/preKote.php

[John D.]

Re: Cast Magnesium

plain water will attack magnesium as i had real mag wheels on some of my mid years and they turned dark just from getting wet. i would say clear coat after cleaning if you want it to stay looking new.

We judges frown on clear coat Clem. Unless u want a ding or two. My old hot rod had real deal mag wheels on it that I ditched in short order for some nice Cragars as I recall.

"mouse fir" is a new term for me. What u don't learn here on the DB. JD

[John D.]

Re: Cast Magnesium

Cecil, Thanks for the good info. Not cheap though but I bet it's good stuff. JD

[Dick W.]

Re: Cast Magnesium

John, let me know if you try the chemicals. I have a set of Chaparell, and a two sets of McLaren magnesium big block valve covers. I would like to find something to clean them. I want to mount them on the wall in my shop. I hope to be getting a set of the semi-hemi small block cylinder heads to put on the wall too.

[Gerard F.]

Re: Cast Magnesium

Joe,

Try a little Eagle Mag cleaner, there are two types, the etching and non etching type. I have used the etching type on aluminum and potmetal, and on a 67 fuel pump, worked pretty good. Try both, then put a little WD40 or TriFlow on it.

[Rex T.]

Re: Cast Magnesium

John, let me know if you try the chemicals. I have a set of Chaparell, and a two sets of McLaren magnesium big block valve covers. I would like to find something to clean them. I want to mount them on the wall in my shop. I hope to be getting a set of the semi-hemi small block cylinder heads to put on the wall too.

Hi Dick,

You have an email message from me.................

[John D.]

Re: Cast Magnesium

John, let me know if you try the chemicals. I have a set of Chaparell, and a two sets of McLaren magnesium big block valve covers. I would like to find something to clean them. I want to mount them on the wall in my shop. I hope to be getting a set of the semi-hemi small block cylinder heads to put on the wall too.

Slim chance DW. You buy the chemicals and then I will send you the bottom cover of my real deal 4657 with no frog pads and you can clean it for me. Nothing uglier though than magnesium. Except for a certain female. I can remember in the olden days buying the 5 spoked expensive american mags that the racers thought were cats ash. Really unattractive no bling wheels. I got rid of them fast.
WE have enough trouble here refinishing FI's that have been blasted. JD