Painting/coating magnesium HRC crankcase cover

dutchness
Edited Date/Time 10/19/2019 7:14pm
Hey guys,

I recently purchased this HRC clutch cover for a Honda CR250 project I'm doing. The original coating is weared out and I want to blast it with water or a fine media on a low pressure and then paint or coat it again. My question is if anyone has experience with coating magnesium parts, and what coating would be the best option? It has to last, prevent the magnesium from rotting and come in the original matte greyish/green finish. My second question is how fast I should coat it after blasting it because of the corrosion.



Thanks!
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ME686
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ME686 9/9/2013 3:34pm
9/9/2013 3:34pm
dutchness wrote:
Hey guys, I recently purchased this HRC clutch cover for a Honda CR250 project I'm doing. The original coating is weared out and I want to...
Hey guys,

I recently purchased this HRC clutch cover for a Honda CR250 project I'm doing. The original coating is weared out and I want to blast it with water or a fine media on a low pressure and then paint or coat it again. My question is if anyone has experience with coating magnesium parts, and what coating would be the best option? It has to last, prevent the magnesium from rotting and come in the original matte greyish/green finish. My second question is how fast I should coat it after blasting it because of the corrosion.



Thanks!
You want tips on magnesium metallurgy, you should look into other fields that mag is used extensively for weight loss. Ill give you a hint. They fly. And if your powder coater doesn't handle magnesium and cant tell you what you should know, walk. If he glass beads it you are gonna have little dots in the finish after he bakes those particles out. Use something soft for blasting. There are several formulations and you can produce different finishes, but the chemicals aren't cheap and super hazardous. Good luck.
dutchness 9/15/2013 3:26am
9/15/2013 3:26am
I won't anodize it, I knew this wasn't going to work. I've looked on the net to some coatings applied in the aerospace business but this is going to cost to much for probably a bad result. The alloy used 20 years ago is not comparable to what is being used right now. I'll have my local painter scan the original color, blast it with a soft media and just going to have it painted. Thanks for the answers.
nine1seven
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nine1seven 9/15/2013 11:29am
9/15/2013 11:29am
You need to find someone who can work with Dow-9. It is what the factory uses in Japan but It is hard to find anyone who works with it anymore in the US. Usually, when you find someone they are located on an airport because Magnesium is extensively used in aviation. Dow-9 is ugly stuff to work with from what I hear. It is used mainly to stop corrosion but they also make fire retardant coatings as Mg burns like the sun! We ignited a Mg wheel off a hawker jet one night and once it started it was like daytime and chunks of concrete went flying off the driveway.

The guy you should talk to is Vital's own 718. He posts on here quite a bit and is one of the only knowledgeable guys who works with these types of coatings.

Those are some cool parts you have. By buddy has some of those as well but none of the power valve assemblies that are required to make them work. If anyone is interested in them let me know. He has multiple covers and they are brand new HRC pieces with paperwork, etc.

DJ
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Donk122
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Donk122 9/16/2013 10:31am
9/16/2013 10:31am
sand blast it to create an even clean looking surface. Then handle the pieces with care because even the natural oil on your hands will affect this... take a bucket, or something, put a good amount of water in it, enough to completely dunk the pieces in and hold them in there... Take normal baking soda you find at the grocery store and dump a bunch in and mix it all up completely dissolving it in the water. take the pieces and dunk them in the water/banking soda mix and depending on how long you hold them in for is how dark they will go. pull out of the water evenly and dont let any drops of water on the piece. Ive had a bucket of just water to dunk in after and rinse. the material must be magnesium. It looks cool, and generally has lasted me a season on my igniton cover and valve cover. then just blast it again and repeat process.

The Shop

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indy_maico
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indy_maico 9/16/2013 2:12pm
9/16/2013 2:12pm
Here is a place in Chicago that does both Dow 7 & Dow 9 on magnesium.

http://www.saporitofinishing.com/contact

If you are in Europe, I would look at places in the UK that specialize in vintage racing cars. They used to use a lot of magnesium on them.

Here is a place to start

www.randjsimpson.com
newmann
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newmann 9/17/2013 7:47pm
9/17/2013 7:47pm
dutchness wrote:
I won't anodize it, I knew this wasn't going to work. I've looked on the net to some coatings applied in the aerospace business but this...
I won't anodize it, I knew this wasn't going to work. I've looked on the net to some coatings applied in the aerospace business but this is going to cost to much for probably a bad result. The alloy used 20 years ago is not comparable to what is being used right now. I'll have my local painter scan the original color, blast it with a soft media and just going to have it painted. Thanks for the answers.
Automotive paints and primers directly over bare mag won't last. The mag will gas under the finish and look like you have an ant farm under it.

The link Indy provided seems to be the go to place as it appears they have it all figured out for mag coatings. You'll notice several of their finishes claim to be a good base for painting over. If you are planning to paint it for a good color match, see if your powdercoat guy can powder prime the part first. I've had a lot of mag parts powdercoated and they've all held up excellent for many years. Pissed away a lot of money on epoxy primers and urethane finishes and had them all fail miserably.
dutchness 9/18/2013 12:46pm
9/18/2013 12:46pm
Thanks for all the answers, I will try to find someone in Europe to do a dow 9 coating, just like it was ment to. Thank you Newmann for warning me about automotive paint, I hadn't thought about that.

@ nine1seven, please bring me in contact with your buddy, I am interested.
indy_maico
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indy_maico 9/18/2013 2:05pm
9/18/2013 2:05pm
Here is a place in the UK that offers Dow 19 for touching up small areas in a do-it-yourself application.

They might be able to help you find someone who can do bigger jobs, or maybe the touch-up will suit your application.

http://www.indestructible.co.uk/DOW-19/
Jmmx
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Jmmx 10/3/2013 2:14pm
10/3/2013 2:14pm
nine1seven wrote:
You need to find someone who can work with Dow-9. It is what the factory uses in Japan but It is hard to find anyone who...
You need to find someone who can work with Dow-9. It is what the factory uses in Japan but It is hard to find anyone who works with it anymore in the US. Usually, when you find someone they are located on an airport because Magnesium is extensively used in aviation. Dow-9 is ugly stuff to work with from what I hear. It is used mainly to stop corrosion but they also make fire retardant coatings as Mg burns like the sun! We ignited a Mg wheel off a hawker jet one night and once it started it was like daytime and chunks of concrete went flying off the driveway.

The guy you should talk to is Vital's own 718. He posts on here quite a bit and is one of the only knowledgeable guys who works with these types of coatings.

Those are some cool parts you have. By buddy has some of those as well but none of the power valve assemblies that are required to make them work. If anyone is interested in them let me know. He has multiple covers and they are brand new HRC pieces with paperwork, etc.

DJ
Hi, your friend has some hrc cases? I have the hrc 250 gov for it, I would trade with cash for hrc 125 parts I need crank and crank cases, rear wheel front brake master or anything you think I could be interested in. Cheers.
Lildriver30
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Lildriver30 10/18/2019 7:31am
10/18/2019 7:31am
nine1seven wrote:
You need to find someone who can work with Dow-9. It is what the factory uses in Japan but It is hard to find anyone who...
You need to find someone who can work with Dow-9. It is what the factory uses in Japan but It is hard to find anyone who works with it anymore in the US. Usually, when you find someone they are located on an airport because Magnesium is extensively used in aviation. Dow-9 is ugly stuff to work with from what I hear. It is used mainly to stop corrosion but they also make fire retardant coatings as Mg burns like the sun! We ignited a Mg wheel off a hawker jet one night and once it started it was like daytime and chunks of concrete went flying off the driveway.

The guy you should talk to is Vital's own 718. He posts on here quite a bit and is one of the only knowledgeable guys who works with these types of coatings.

Those are some cool parts you have. By buddy has some of those as well but none of the power valve assemblies that are required to make them work. If anyone is interested in them let me know. He has multiple covers and they are brand new HRC pieces with paperwork, etc.

DJ
Anything fornam 1986 cr250r?
OldPro277
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OldPro277 10/19/2019 7:14pm
10/19/2019 7:14pm
Lildriver30 wrote:
Anything fornam 1986 cr250r?
Dude, this thread is 6 years old......

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