Neutralising Mag Rot

[flatsfisher]

anytime I strip anything aluminum or magnesium to bare metal for painting, I do an Alodine conversion coating. it creates a thin chromate layer. the process involves treating with a mild acid, washing and then Alodine coating. it's a very simple process. followed by primer and paint. will put up pictures of the 2 chemicals I use later today.

this is not what I use but a commercial treatment I found online.

"Henkel Alodine magnesium treatment kit is designed for touch-ups and the corrosion repair process of magnesium parts. Henkel's magnesium treatment can also be used to passivate the metal and prevent corrosion. Its application method conforms to NAVAIR 01-1A-509 requirements."

 

[flatsfisher]

here are the 2 products I use. the clear one is the etch, the brown one is the Alodine treatment. I bought this originally for aluminum corrosion but have also used it on saws. there are other types of Alodine that are more specific for magnesium. this stuff is used extensively in the airplane industry. no one in that field paints aluminum or magnesium parts with using a form of this.

 

[farmhard]

here are the 2 products I use. the clear one is the etch, the brown one is the Alodine treatment. I bought this originally for aluminum corrosion but have also used it on saws. there are other types of Alodine that are more specific for magnesium. this stuff is used extensively in the airplane industry. no one in that field paints aluminum or magnesium parts with using a form of this.

View attachment 1135832

looks like vinyl wash.

 

[Gord404]

Heat will bring oil out of the pores.

I’ve cleaned it up with carb cleaner and a brush and then covered it with JB weld 7-8 years ago. JB is still there

How about inside of the crank cases, will JB hang in there?

 

[farmhard]

How about inside of the crank cases, will JB hang in there?

I sandblasted, used vinyl wash and then POR15 gas tank sealer. I don't know about JB as far as being resistant to gas or fuel, I wouldn't want to take the chance. It seems to work for everybody but me lol. If I did use JB I would coat with gas tank sealer over top.

 

[flatsfisher]

looks like vinyl wash.

don't know what that is.

 

[farmhard]

don't know what that is.

Vinyl wash and zinc chromate primers are a sprayable alternative to dipping. That Alodine is some pretty nasty stuff environmentally but seems to give a nice finish like yellow cad. Basically an anodizing material without electrical current.

 

[flatsfisher]

Vinyl wash and zinc chromate primers are a sprayable alternative to dipping. That Alodine is some pretty nasty stuff environmentally but seems to give a nice finish like yellow cad. Basically an anodizing material without electrical current.

Zinc Chromate is a CARCINOGEN in humans. It has been shown to cause lung and throat cancer. * Many scientists believe there is no safe level of exposure to a carcinogen.

ZINC CHROMATE CAS Number - NJ.gov​

New Jersey (.gov)

 

[flatsfisher]

just sayin.

 

[farmhard]

Zinc Chromate is a CARCINOGEN in humans. It has been shown to cause lung and throat cancer. * Many scientists believe there is no safe level of exposure to a carcinogen.

ZINC CHROMATE CAS Number - NJ.gov​

View attachment 1135903
New Jersey (.gov)

It doesn't have to be in chromate form, zinc itself it one of the most toxic elements.

 

[singinwoodwackr]

What about some sort of body filler? I know there are all sorts of products out there better than the old Bondo. Some with metallic components that are even magnetic.
I have a 372 to build that has some rot on the clutch side case. So far ive cleaned and dremel wire wheeled it.

 

[Woodslasher]

How about inside of the crank cases, will JB hang in there?

I think @heimannm has jbwelded the inside of a crankcase before, in addition to rebuilding a kart motor with it.

 

[singinwoodwackr]

I think @heimannm has jbwelded the inside of a crankcase before, in addition to rebuilding a kart motor with it.

Randy (mastermind) has used JB in intake ports.

 

[farmhard]

If the metal is clean and no oil leaching out JB is the go to product. I stated above that panel bond and metal adhesives for body work did not work on my oil pan ): when van slipped off a floor jack. I personally can not ever get satisfactory results that I am happy with out of JB. It held up on the wife's Jred though I didn't apply it.

 

[farmhard]

I used gas tank sealer inside crank cases. Not sure how long it will last but if a chunk of JB comes loose could be some worser issues.

 

[huskihl]

How about inside of the crank cases, will JB hang in there?

Yes it will, as long as it’s clean first

 

[huskihl]

I used gas tank sealer inside crank cases. Not sure how long it will last but if a chunk of JB comes loose could be some worser issues.

The reason JB is used is because it’s soft and crumbles easily. Preparation is the key to making it stick.

 

[heimannm]

Crankcase has some serious corrosion, I put it in the sandblast cabinet and cleaned it up only to find some holes through the bottom.



I warmed it up with a heat gun to help the JB flow out and kept rocking it back and forth to achieve an even layer.



I don't run it a lot, but 8 years later it is still fully operational and there are more than a few guys on the forum that have seen it in operation or have run it.





Mark

 

[Lightning Performance]

It doesn't have to be in chromate form, zinc itself it one of the most toxic elements.

Welding galvanized or other processes that release zinc is the main issue with products containing zinc. Zinc phosphate primer is all I've ever used on galvanized panels, spray bomb style or in gallons, aluminum cast or billet, magnesium or other non ferrous alloys like the stuff. It even sticks to copper. Remove the grease and oils with soap or metal conditioner then dry it for a day. Sand or scotchbright. Once that zinc primer sets it won't come off. One coat only transparent. Biggest mistake is two coats or one heavy coat. No need to bake it like some epoxy primers. It just sticks to everything that was well prepared. JB sticks to it. So does silicone and gorilla snot. Pig putty and gastank sealer won't come off.

Using that two part chromate takes too long but does lock down corrosion pits and prior issues. I feel zinc primer does the same thing in a dry environment. Burning out the cases over a 350°F bbq or outdoor oven helps a bunch. We couldn't do that with stuff containing rubbers, plastic or gaskets. Galvanized cowl panels can't be baked either, opps. They twist badly. Cast aluminum stuff can be cooked near 400°F no sweat like intake manifolds or exhaust manifolds.

 

[Lightning Performance]

The reason JB is used is because it’s soft and crumbles easily. Preparation is the key to making it stick.

Grey smoke is about the worse thing that happens. Silicone sealer does more damage rattling around in an engine imho.