Mag case finishing

[zztot]

So beating one around…..Have had case work done but debate is with finishing.
One school of thought is making mag case nice in appearance is short term proposition so why bother.
Builder whose primary experience is with aluminum feels “pretty” is important.
While I’d like to have nice case not sure the short term results are worth cost/effort.
Second issue is locating a media tumbling place within a reasonable distance as don’t want to ship. I’m in Florida panhandle but Atlanta is viable as is Pensacola / mobile.
Thoughts.

[PeteKz]

I assume this will be a driver of some sort, not garage art.

It's hard to get paint to stick to old magnesium castings. Therefore I would leave it "au naturale," 'cause it's probably gonna end up that way anyway.

Tumbling the case in any kind of abrasive media would get a bunch of it into the case passages, where you would spend an inordinate amount of effort to get it back out, and you risk leaving some behind despite your best efforts.

Clean up the outside by hand and block internal passages to keep crap out of them. Done.

[zztot]

It is going to be at high level BUT your point is well made. Why create the risk when it comes with great peril……all for temporary result.
Thanks

[Flat6pac]

They don’t shine, they’re 70 years old, turning a flat dark grey.
Grease is off, corners are clean, build it.
Bruce

[zztot]

👍👍👍

[mepstein]

No matter how clean and shiny you make it, mag will go grey pretty quickly. We vapor blast mag trans cases but then put them into our ultrasonic. It not only cleans the case but makes it turn grey in 5-10 minutes. For us, grey is the right look for mag.

[buster73]

I have used "Boeshield T-9 Corrosion Protectant" (Aviation supply such as Aircraft Spruce) for my Mag and Al engine and transmission parts for many years. Parts will also darken over the years but the spray-on wax will reduce risk of corrosion. Do not spray it onto cylinders and heads as the wax will impact heat transfer and avoid hot components (exhaust) as the wax will burn off.

[Dpmulvan]

Gibbs

[SalParadise]

As most have said, it's going to turn gray no matter what. The guy who did the engine in my car 25 years ago decided to rattle can the parts you can see with silver - and it quickly rubbed off to gray. Unfortunately it is what it is. Leave it alone.

[zztot]

Understand……can’t change DNA……of magnesium. Got some interesting information on vinegar……but still all comes back to it being temporary. Not trying to be blockhead just making sure I have covered all bases.
Thanks for all the input.

[stcan]

Originally Posted by mepstein

No matter how clean and shiny you make it, mag will go grey pretty quickly. We vapor blast mag trans cases but then put them into our ultrasonic. It not only cleans the case but makes it turn grey in 5-10 minutes. For us, grey is the right look for mag.

What solution you use in your ultrasonic cleaner to get the grey look

[mepstein]

Originally Posted by stcan

What solution you use in your ultrasonic cleaner to get the grey look

We buy the cleaning solution from ultrasonic LLC where we got the machine.

[Tippy]

How about spraying the cases down with Corrosion X after rebuild?

Stuff prevents corrosion amazingly and it is cheap.

[SalParadise]

I really don't know if a corrosion spray even matters. Soon enough there is going to be a light film (or more) all over that new engine no matter what (it's going to happen). I think the spray would be more beneficial on a mag transmission - that's the place where if there isn't a ton of oil, sludge, road grime, etc on it by now protecting it it's going to corrode. At least that's the story with mine when I cleaned it all off - and it took a day.

[porschedude996]

Cerakote has a Satin Magnesium paint that is very real looking. Air Dry, no oven cure. In fact is is already to shoot from the container.

Words from experience.
1. Place some clean stainless steel nuts in the container to help agitate the mix.
2. Strain the paint going into the gun.
3. Spray semi dry. No heavy coats. Several very light coats initially.
4. Small Metallic runs seem to disappear. Large ones don’t. You can blot some to remove when wet with a paper towel.
5. Can be touched up easily.
6. Us grease and wax remover and tack rag.
7. Small paint booth will keep from getting dirt in the paint. It doesn’t need to be a full blown paint booth, may a cardboard box of you msking.








I know, I know, I went way overboard on my spray booth.

[thetorch]

I second @dpmulvan's advice: Gibbs on magnesium looks good, easy to reapply periodically. Just put it on after you've buttoned up the case.

I love ceramic coating, but not for this use case. Don't overthink it.

My mag case 915. Only cleaned it with brakekleen. Doesn't attract dirt once it sets up.

[gled49]

A third for Gibbs. Mag dries out, it need to be hydrated with oil. McLaren use to recommend dipping Mag uprights in hot ATF. I low pressure plastic media blast case pieces to get scale off, after assembly I Gibbs it.

[zztot]

Good look!

[RobFrost]

If you want a proper finish you can get an aerospace metal finisher to treat it with iridite #15 then powder coat or cerakote will stick. But check what that iridite will do to your machined tolerances etc. and whether they can apply it only to the outside. Part of the process is a hot alkaline bath to clean it and another is an acid etch. It does involve a chemical reaction with the magnesium.

I would still oil or wax the outside afterwards though, to keep water off.

I'm about to go through this process with my engine covers, mfi stacks etc., before I decide what to do with my engine case.

Sent from my SM-S918B using Tapatalk

[stcan]

What did you use to clean the mag case? Looks very clean

Originally Posted by gled49

A third for Gibbs. Mag dries out, it need to be hydrated with oil. McLaren use to recommend dipping Mag uprights in hot ATF. I low pressure plastic media blast case pieces to get scale off, after assembly I Gibbs it.