olmann

This is the process I used for refinishing my intake and cam covers. I researched the best process to refinish the aluminum/magnesium (Al/Mg) alloy and came up with this process. I wanted to have more of a variety to color schemes then offered through most powdercoaters. When inquiring around to all the local paint shops and metal finishing companies, no one was willing to touch magnesium to refinish with any type of guarantee it would work. The problem seemed to be that there was no good way to etch the Mg alloy so that you could get a good base for the primer to stick. Even the factory process could be improved upon as we see our current intakes paint peeling off. My searching lead me to a chemical company out of Chicago (Sanchem) that offers a converter for magnesium alloys. The conversion coating I used is the SafeGard CC-3400 RTU (Ready To Use) that runs $40 for a gal. I used about 12oz for the entire process. http://www.sanchem.com/safegard_cc.html. This converter essentially etches the metal alloy and allows for a primer to be applied that will result in excellent adhesion to the metal. I spoke with the lead chemist and he seemed to be familiar with the type of Al/Mg alloy that was used in the production of the intakes and cam covers. He then lined out the process I needed to follow for best results as the converter is time dependant.


First obvious step is to have the parts stripped. Chemical stripping is too harsh and sanding is too time consuming so I decided to have the parts blasted. I chose to go with aluminum oxide blasting. Aluminum oxide isn’t too aggressive and I didn’t need to worry about beads being left behind. Here are the parts after the blasting process. They come out a bit rough to the touch.





When I got these parts back I blew them clean with compressed air. Once I had that done I completely washed/immersed the parts in white vinegar. The parts will fizz and get real warm as the acid reacts with the Al/Mg. Continue to soak them for a few minutes and then wash them clean with distilled water and let dry. Here are some additional photos after that process. The vinegar acid bath seemed to smooth out the roughness from blasting and take care of any of the aluminum oxide blast media left behind.





Once that had dried completely I spray/coated the parts with the converter, let it soak for a few minutes and then wipe/air dry.




Once the part is dry you have a 2 hour window to apply primer. If you don’t get it sprayed in that time frame the primer will not make a good bond. You will have to go back to the vinegar step and start over. I chose to use Dupont’s ChromaSeal urethane sealer. Since the converter acts the same as an etching primer, I went straight to the sealer. The sealer gives a nice level smooth surface that you can paint over with no sanding. Here again it is time dependent. Follow the manufacturer’s recommendations but you can topcoat after about 1 hour and up to 16 hours. After that you will need to sand the primer to promote adhesion. This product has excellent leveling for the topcoat and EXCELLENT adhesion with the converter. If you would ever want to repaint it down the road you would just have to scuff sand it and repaint. It would not need to be striped again due to having the good base sealer in place.







I sprayed a factory Porsche color with Dupont’s ChromaBase paint and a high temp engine clear over that. In hindsight I wish I would have used the ChromaBase high performance clear as the high temp clear has yellowed a bit but not too bad. The color has a pearl essence in it so it changes color a bit depending on the light. If you would prefer to skip the clear coat, you could just go with a single stage paint that would need nothing else once sprayed. It’s all personal preference. I did this approximately a year ago and have had no issues. When reassembling the intake I wanted to level off the surface area of the intake where the intake gasket goes for mounting to the engine. I had to aggressively sand it down to get it off. Even then the primer didn't want to come off easily. Its adhesion is excellent and you can see from the pic where I worked to get it off.



Here is the final product. I hope that this helps others who would like an alternative to powder coating. Thanks

pcar928fan

Looks awesome!

SMTCapeCod

Wow ^^ New guy with the big win!
Just kidding, I can tell by your post and your sig that wouldn't be an apt characterization.

Beautiful outcome- you could have quite a cottage business on the side doing that, I expect.

I like the slight hue/patina that it has acquired too...Just, wow. Thanks for posting up the source info, process and results.

jbrob007

WOW! That is beautiful! Someone needs to make a STICKY out of this post so I can find it once my painted intakes start peeling... I just finished my paint job last week - it looks great, but not sure how long it will hold up - we'll see

Thanks for the info and the step by step procedure!

Joel

77tony

Saw these at 3rd Coast this past Nov and they did look great. Nice job Brian. 77Tony

jbrob007

See if I can post a pic or two... Paint works if you do the prep. And, I did a TON of prep. Wish I had known about this etching material a month ago! Oh well, maybe next time

UncleMaz

That looks awesome. I wish this thread was started before I painted mine. Your beautiful work makes mine look like ***. Thank you for posting.

aaddpp

That looks really sweet. Nice job.

Rob Edwards

Outstanding!

When the chemist was 'familiar' with the Mg/Al alloy, did he specify a particular type or composition? Just curious.

NoVector

Outstanding--just bookmarked this page for my top end refresh. After it's stripped, is it possible to lightly sand and fill some of the pits to get a really smooth surface? If a filler can be used, what kind would I use that wouldn't mess up the rest of the process?? Again, great job! / Bruce

SeanR

That looks very very good. Well done.

Herman K

PM send, thanks for posting

jeff spahn

I'll look at this route in several years when i re-do my intake again. I am not really happy with the silver color that got powder coated and will try to get something closer to what the OP shows.

Bertrand Daoust

Nice job.
Congradulations.
Very well done.

JWise

Anyone who's had a chance to talk to Brian will come away impressed - he's very knowledgeable, thorough, and detail oriented. I had the pleasure of meeting him and seeing his car in person at 3rd Coast. His car was incredible and the intake looks better than factory.

About two years ago, I painted my intake and cam covers with Duplicolor Engine Enamel on top of their self-etching primer. It's held up well, although there are a few places where it has started to bubble, most notably in the cam cover lettering. Note: I did not throroughly strip mine, rather I removed everything that was loose then feathered the edges in with primer and sanding. As such, you could say my prep work was subpar.

I'm not a big fan of powdercoating and will bookmark this thread for use next time. I suspect Brian's method will hold up at least as good as the factory's did, and possibly better given modern materials and our own attention to detail. Thanks for the writeup!