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Thanks Guys, for the support.
Honestly, as good as it looks now, I need to monitor the surface since this is a relatively unknown for me with this product on this alloy.
So far so good, however, some of the components have been exposed to air for several weeks after treatment without oxidation. Now we will see if heat is an issue, since the car is back together and running.
Just wanted to check in on this.
Noticed oxidation on the intake this week.
Looks like the Sharkhide gave up.
I guess the magnesium component was too much for it after all.
For those that doubted it would work...keep doubting.
Just wanted to check in on this.
Noticed oxidation on the intake this week.
Looks like the Sharkhide gave up.
I guess the magnesium component was too much for it after all.
For those that doubted it would work...keep doubting.
Hey Dave,
Any pics? I was interested in this approach.
It seems like it did the job for about 2 years? About how many miles did it last do you think?
Could it be it needs to be reapplied? (which could be a pain...)
In as cast condition Magnesium has a skin on it that if left alone will last a fair time assuming it is not soaking in water or in a very moist environment. The easiest approach is to find someone to grit blast and chrome pickle the parts immediately after blasting. The chrome pickle is a chemical conversion basically a mixture of nitric acid and sodium dichromate dihydrate. Nasty stuff. You can buy this mix it and apply per MIL/AMS M 3171. It is the easiest way to prevent oxidation but should be painted soon after. There are some decent catalyzed paints you can use that are not perfect but will hold up to solvents which is a must for engines.
There are no guarantees it will hold up but you might consider their clear over the polished but I have never seen that last.
Another option is finding a shop that can do the passivation for you. This shop is local to me and does excellent work but call to verify they can help you. http://qualitymetalfinishing.net/
PS: it may not appear to be oxidizing but it starts within an hour or so after cleaning. You can't trust your eyes. Rule of thumb is some form of coating or conversion within an hour of cleaning. Also oils from your hands will clearly show up as fingerprints or black marks after a while. If this is allowed to sit for weeks it might show up after you coat it but years from now.
Magnesium is great metal but is temperamental. I would consider polishing any surface that has not been treated again prior to coating with anything. Also a good wash and dry at 120 degrees in a convection type oven is also wise.
Also others said that the gray powdery surface is from a conversion treatment. that is incorrect. Depending on hardness the magnesium will show up as a greenish gray to gold color not powdery. If it is gray powdery be careful this can be explosive if sparks are nearby.
It seems like it did the job for about 2 years? About how many miles did it last do you think?
Could it be it needs to be reapplied? (which could be a pain...)
You can compare the side air box to the raw aluminum. Not terrible yet, just much duller then before. I would estimate two years and 8000 miles since application.
You can strip off the sharkhide with lacquer thinner and re-apply pretty easily, but I think the oxidation would require the same prep as before to make it look perfect...which I don't have in me again
Originally Posted by cobalt
In as cast condition Magnesium has a skin on it that if left alone will last a fair time assuming it is not soaking in water or in a very moist environment. The easiest approach is to find someone to grit blast and chrome pickle the parts immediately after blasting. The chrome pickle is a chemical conversion basically a mixture of nitric acid and sodium dichromate dihydrate. Nasty stuff. You can buy this mix it and apply per MIL/AMS M 3171. It is the easiest way to prevent oxidation but should be painted soon after. There are some decent catalyzed paints you can use that are not perfect but will hold up to solvents which is a must for engines.
There are no guarantees it will hold up but you might consider their clear over the polished but I have never seen that last.
Another option is finding a shop that can do the passivation for you. This shop is local to me and does excellent work but call to verify they can help you. http://qualitymetalfinishing.net/
That sounds good sir, I will research.
I will put take two back in the que, I gotta deal with some other stuff first.
Wow, you all seem to make this entire process so challenging and time-consuming! I just did this to my S4.
All done, Plastic Media Blasted, wiped down, epoxy primed, and a 'Dull Aluminum' paint and hand painted in Guards Red the letters.
Pile to be blasted
Correcting some casting flaws
Left one original for comparing.
Nothing escapes getting blasted by the Doctor at www.drblast.com
Before
Sick and needing a cure
Nice and clean
The only way to do this, professionally Media Blasted. No chemicals, no dremel tools, no sanding, no hours and hours and hours, no residual blasting media anywhere.
Magnesium can be a tricky material and damage can be occurring under the PC without you ever knowing. Intakes are not critical parts but for some items it can have a very negative impact. Once oxidation starts attacking the metal at a dendritic level there is no turning back. The question is are you looking for a few years or a lifetime finish.
01-31-2015, 05:49 PM
