Magnesium Chromate Coating

[SiracHaile]

I recently had my mag case vapor blasted and I’m not too happy with the finish of the magnesium. This process makes aluminum look like jewelry but doesn’t look to well on old magnesium.

The case has the typical corrosion and small holes where the media can’t reach to clean and I’m looking to getting it coated and the finish more uniform to the original dark grey color.

I’m in Southern California so I’m sure there are places that do it around me but I don’t know what it’s called or who to ask.

Can this coating be done after machine work to the case?

Thanks

[Zuffenwerker]

Vapor blasting mag is not a good idea it will be interesting to see your solution! Next time just have the case tumbled it produces awesome results on old mag cases. Please post pics if you perform a coating or treatment!

[mepstein]

It will turn grey. Mag is a very reactive metal. You can mirror polish and it will go back to grey. You can speed it along with different solutions but it will happen in time no matter what you do. Once you build up the engine. all the pitting and corrosion will be covered up by the cylinders, engine tin and fiberglass shroud. Unless you have to have beauty shots of the case, don't sweat it, you wont see it again.

[john walker's workshop]

What about the vapor blast bead particles in the oil passages and behind the squirters?? It ain't just vapor.

[mikedsilva]

Originally Posted by john walker's workshop

What about the vapor blast bead particles in the oil passages and behind the squirters?? It ain't just vapor.

This is why I have never had one done. You would need to pull all squirters and all case plugs then flush like crazy. I'd still be a little unsure you'd get every bit of media out....

[OSC911]

Originally Posted by mikedsilva

This is why I have never had one done. You would need to pull all squirters and all case plugs then flush like crazy. I'd still be a little unsure you'd get every bit of media out....

Hey Mike
I've seen your completed engines which come up very nice indeed. Do you get them tumbled then instead of vapour blasting?

[mepstein]

We've vapor blasted a bunch of engine cases. They get washed in a big parts washer, ultrasonic cleaned, etc. It's not much different from an engine that's spun a bearing and has metal dust everywhere. It all gets cleaned up.

[SiracHaile]

The case is with Ollie’s and they are well aware of what was done. The case will be cleaned thoroughly all plugs and squirters removes and flushed.

I spoke with Tim at Ollie’s and he said he has a process to get it back to its original color or close to it. I’ll just have to wait and see.

[Jeff Alton]

It will turn dark grey shortly. Vapor blasting still can imbed media in the parent material. Not the best solution. We solvent clean then put them in our jet wash. Just finished one that still needs hand cleaning of gasket surfaces by the client. Will try to get some pics of it over the weekend.

Cheers

[SiracHaile]

Originally Posted by mepstein

We've vapor blasted a bunch of engine cases. They get washed in a big parts washer, ultrasonic cleaned, etc. It's not much different from an engine that's spun a bearing and has metal dust everywhere. It all gets cleaned up.

That’s my understanding as well. The case was also blasted closed so the internals were not blasted with media.

I was told the lead time was about 16 weeks for the machine work and the case work so I’ll just wait and see.

[Dpmulvan]

To learn more about vapor blasting I suggest this https://www.vapormatt.com/applications
You’ll find most of the negatives mentioned totally untrue.

[superninety]

What about soaking it in Gibbs Oil or similar? I open this idea for the more informed. Historically Gibbs has been considered as a protectant/preservative for Mag parts.

I have used it on fan shouds successfully.

[buster73]

I have good long time experience with Boeshield T-9 corrosion protection. Used it an my Mag 915 case, Mag 7R case and Mag parts such as fan and fan housing. Surface will darken somewhat but as mentioned by others, Magnesium will not stay shiny very long anyway.

[icarp]

every day spray the case with WD40
we have been doing it for the last 50 years
Ian

[safe]

Pull all plugs and squirters and clean it like you life depended on it. Otherwise the finish will be the last of your concerns.
I have a friend that bought a fresh engine build where case was blasted and the plugs was not pulled when cleaned. The engine was a total loss after 100 miles (almost, the heads are reusable).