Magnesium corrosion help

[Brandon G]

I just pulled out my YZ-10 to do a little work on it and I noticed the rear bulkhead/motor mount had some white residue on it that wasn't there before. The front bulkhead is completely fine though.

I was wondering if anybody else has had this problem?

I have been looking this up on the web and it seems that moisture will cause this corrosion, but I have been keeping this car stored in a climate controlled 10X20 building. I don't think that moisture is truly the culprit. I have loose Sanyo SCR cells in the chassis itself, I think this may have something to do with it. I need to pull them out and store them seperate from the chassis in a sealed bag, but I have been lax in my efforts.

I noticed I have the same thing happening to some pan cars with the magnesium front beams as well. No batteries have been stored in those chassis'. I do not store chemicals in the building, but I wonder if the pressure treated siding that the building is made of may be causing this?

I guess at this point I need to remove the part and bead blast the junk off of it to prevent the future spread. I thought about lightly spraying the parts with a clear coat if it is just an atmospheric reaction causing this. Or finding a good source for corrosion impregnated bags to store the buggy in. Seems like a low cost way to help preserve a valuable car.

Any input?

[kaiser]

magnesium is a pain. my vw beetle's engine case is magnesium and every time i have it out if get all the power off of it only to have it reappear in a few weeks. not much you can do. painting doesn't work, the corrosion will "push" the paint off.

maybe powdercoat?

wax works though, only if the part doesn't get hot, so it's useless on my enging but may be a good alternative for your bulkhead.

[Charlie don't surf]

My WCS has turned black in the 30+ month build, my boxed 870c looks new though-

[RichieRich]

Magnesium will do some weird stuff when near or touching other metals. I think your only option would be anodizing or painting. Though, you'd first have to strip the top oxide layer off the magnesium which could get chemically messy.

[jwscab]

magnesium LOVES oxygen, ie, it's a very reactive metal. As mentioned, it also has quite a galvanic reaction when in contact with other metals, particularly steel. For any screws, you could potentially use some mineral oil on the threads to help keep oxygen away and provide some insulation between metals.

you can clear coat it, and I also believe that most VW/Porsche shops recommend a wax type of coating on items that don't get really hot. the problem is that anything that can allow oxygen through will get bubbled up as the oxide flakes up as mentioned.

For some of the yokomo stuff I have, I plan on bead blasting and then using a spray on semi-gloss clear coat. In a controlled environment, this should give you decent protection.

If that doesn't work, I'm going to do a wax dip kind of thing after bead blasting. currently the parts I have are all in a ziplock bag, keeping much of the oxygen away from it.

once assembled and not on display, your best bet would be to bag them up with any kind of good thick poly bag with some silica gel packs to keep oxygen and moisture out.

[scr8p]

brand new parts still in the package aren't any nicer than ones on built/used cars. every bulkhead/motor mount i ever picked up for someone at a local hobby shop i glass beaded it before i even sent it to them.

a light coat of clear should hold up for awhile. i often wonder about soaking the part in oil and let it weap into the pores.

[kaiser]

*****warning, the below suggestion is the sole opinion/suggestion of the insane poster and in no part recomended by rc10talk*****

for fun, if you have a scrap piece toss it in a fire, right on the hottest coals, just make sure the part is small because you cannot put it out, it has to burn out. crazy stuff, burns white hot and will burn under water. i think the only way to put it out is with some sort of foam or a ton of halon.

and to think people think lipos are dangerous.

[Charlie don't surf]

*****warning, the below suggestion is the sole opinion/suggestion of the insane poster and in no part recomended by rc10talk*****

for fun, if you have a scrap piece toss it in a fire, right on the hottest coals, just make sure the part is small because you cannot put it out, it has to burn out. crazy stuff, burns white hot and will burn under water. i think the only way to put it out is with some sort of foam or a ton of halon.

and to think people think lipos are dangerous.

I think your confusing magnesium with phosphorus.

[Dirtdiver]

Magnesium is very hard to put out when it is on fire as it reduces water. It has a very bright flame (white) and can be smoothered by sand.

It comes in useful for starting a fire.

Not sure if high school chemistry kids get to play with it anymore but in the 80's we got to light it (very small piece) on fire in chem lab. We also got to see sodium burn, play with mercury and made chlorine gas in the chem lab sink (all done under the watchful eye of our chemistry teacher).

[jwscab]

All the light metals are very reactive, starting with hydrogen. They get progressively less reactive as you move down and to the right of the periodic table. Lithium, sodium, magnesium,etc all the way down.

[Charlie don't surf]

I learn something new everyday

[jwscab]

I heard you were goin' back to college, so I'll help ya out where I can

[losiXXXman]

and electronegativity goes in the opposite direction, right? Now just simplify the triple point for metallurgy and we'll be goo

Off topic, but anyone know what can be used as a substrate for laying up some fiberglass or CF cloth w/ epoxy resin? (without the epoxy permanently connecting the peice to the mold?

[jwscab]

Wax or silicone or polyethylene

[Charlie don't surf]

and electronegativity goes in the opposite direction, right? Now just simplify the triple point for metallurgy and we'll be goo

Off topic, but anyone know what can be used as a substrate for laying up some fiberglass or CF cloth w/ epoxy resin? (without the epoxy permanently connecting the peice to the mold?

Linoleum counter top material works well-