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914World.com _ 914World Garage _ How to grind/dress magnesium

Posted by: TargaToy Feb 4 2020, 03:59 PM

I've seen pics today of members' cleaned up/polished transaxles and noticed that the casting flashing has been removed in some instances--giving a much cleaner look.

I know that magnesium is volatile in that grinding or cutting, creating too much heat, can cause a flash fire.

What's the best, SAFEST, way to remove flashing from the housing?

Posted by: burton73 Feb 4 2020, 04:29 PM

As nice as Dicks transmission looks in the pictures it will roll back to a nice grey color after some time. It may take a year or more to do that but it will. I had a Magnesium 5 lug Gas Burner polished to a chrome look to see how it would age. After some time, it got a milky white coating on it. I decided that the other 4 wheels should just be painted in silver like the wheels from the factory.

There have been a lot of 914 articles on Mag and painting it.

I do know of a magnesium small fire that happened at Bieker Eng. in the late 70s but it was put out with the right fire extinguishers (Class D fire extinguishers are used on combustible metals. These include magnesium, sodium, aluminum, and titanium) This was from machining a Eng. case

In high school the teacher in Science burned some Mag ribbon. Super bright.

Use a small die grinder and take at easy but why bother. The wire wheel like Dick used will give you that look and that is much better than paint.


Eric restored my 914 trans on 41 with Walnut shells I think it Looked good and was realistic of what these old funky looking cases can look like. Sorry I do not have a picture handy


Bob B
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Posted by: mepstein Feb 4 2020, 05:42 PM

Mag is very reactive. If you want it to stay pretty, you have to paint it.

Posted by: TargaToy Feb 4 2020, 05:57 PM

I’m fine with paint but was just thinking that, like engine blocks I’ve painted in the past, the finish looks better when the sharp edges and casting marks are knocked down first.

And honestly, I don’t care that much about a show car undercarriage, but the side shifter I picked up to rebuild had a bit of a texture to it when I did the initial degreasing. It looks like it would resist goop and grime better if the surface was smoothed and/or sealed a bit.

Posted by: mepstein Feb 4 2020, 06:57 PM

QUOTE(TargaToy @ Feb 4 2020, 06:57 PM) *

I’m fine with paint but was just thinking that, like engine blocks I’ve painted in the past, the finish looks better when the sharp edges and casting marks are knocked down first.

And honestly, I don’t care that much about a show car undercarriage, but the side shifter I picked up to rebuild had a bit of a texture to it when I did the initial degreasing. It looks like it would resist goop and grime better if the surface was smoothed and/or sealed a bit.


McMark has epoxy painted them and Ben used Cerikote. - http://www.914world.com/bbs2/index.php?showtopic=330939&hl=epoxy




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Posted by: DickSteinkamp Feb 4 2020, 06:58 PM

My case that i pictured was not ground any...just the fine wire wheel.

I agree that the shine will not last long. I think a year is generous. It's just that I'm a little OCD. smile.gif

Posted by: mepstein Feb 4 2020, 07:03 PM

QUOTE(DickSteinkamp @ Feb 4 2020, 07:58 PM) *

My case that i pictured was not ground any...just the fine wire wheel.

I agree that the shine will not last long. I think a year is generous. It's just that I'm a little OCD. smile.gif


I vapor blasted a mag trans. It looked almost like aluminum for a while and then oxidized to grey.

Posted by: 914_teener Feb 4 2020, 07:14 PM

Exothermic Cerikote or leave it alone.

It gets hot.

Posted by: TargaToy Feb 4 2020, 07:37 PM

Cerakote? As used in the firearms industry? Now THAT’s an interesting idea!

Posted by: mepstein Feb 4 2020, 07:55 PM

QUOTE(TargaToy @ Feb 4 2020, 08:37 PM) *

Cerakote? As used in the firearms industry? Now THAT’s an interesting idea!

Ben painted some repaired 911 engine fans and shrouds for me and he did some S calipers that looked great.

Posted by: 914forme Feb 4 2020, 08:57 PM

QUOTE(TargaToy @ Feb 4 2020, 08:37 PM) *

Cerakote? As used in the firearms industry? Now THAT’s an interesting idea!

YEs, it is used on a lot more stuff than just firearms shades.gif

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