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Posted by: sean_v8_914 Dec 17 2010, 10:56 AM

the MFI throttle body housings appear to be magnesium.
what is good to clean mag?
what is BAD to clean mag?

Posted by: realred914 Dec 17 2010, 11:06 AM

carb cleaner will work, a bit of adbrasive can help, steel wool?

Posted by: SLITS Dec 17 2010, 11:10 AM

http://www.ehow.com/how_5863187_remove-corrosion-magnesium-aircraft-parts.html

Posted by: sean_v8_914 Dec 17 2010, 11:15 AM

Chemical Removal of Corrosion
1Mix a chromic acid solution. The solution should contain 24 oz. of chromium trioxide mixed with 1 gallon of water in a stainless steel, lead-lined steel or 1100 aluminum container.

2Apply the chromic acid solution with a nonmetallic bristle brush. Allow the solution to set on the area for 15 minutes.

3Rinse the solution off the treated area. Use clean water and rinse thoroughly.

Posted by: sean_v8_914 Dec 17 2010, 11:15 AM

thanks ron. I googled it but came up with the ussual internet bs

Posted by: SLITS Dec 17 2010, 01:47 PM

Personally, I would use a bead blaster with glass beads because I have one. After that I would paint them Periwinkle.

Eric

Posted by: Richard Casto Dec 17 2010, 02:39 PM

Chromic Acid is bad stuff and because of that it is getting very hard to find for average people. I love how the eHow article has a "Tips and Warnings" section and says nothing about the dangers of Chromic Acid. Unfortunately most info you find regarding cleaning/protecting magnesium focuses on Chromium related stuff.

As mentioned above, personally I would use Soap/Water and then Mineral Spirits to get any dirt/grease off. Then bead blast with glass beads and then paint. I have been trying to do some research into the best way to prep Magnesium for paint and again the #1 method involves various Chromium related methods (which I don't want to do due to health and disposal issues).

If you have to go the Chromic Acid route, I think you might be able to find Chromic Acid based "touch up" at http://www.aircraftspruce.com/ But that really is for paint prep and would be overly costly for cleaning IMHO.

Posted by: Cap'n Krusty Dec 17 2010, 02:48 PM

I use "Gibbs Brand" to clean, restore, and protect magnesium alloy parts.

The Cap'n

Posted by: burton73 Dec 17 2010, 03:12 PM

I used fresh safety solvent to remove the dirt and grease from my trans. With the brush that was on the end of the power pump. It cleaned all of the crap off with some time and work from my guys. I do have a few cans of Gibbs Brand at my place if you want one to try that. Some people swear by it.

Bob B

Posted by: sww914 Dec 17 2010, 08:43 PM

I've had excellent results with solvent, then Purple Power or whatever that Castrol purple stuff is called, then steam cleaning. Fortunately we have a steam cleaner installed at my shop, the heat really gets the junk off.

Posted by: sww914 Dec 17 2010, 08:44 PM

Oh yeah, the dishwasher is a great last step too. Do it when your wife is gone or she'll blow a fucking gasket.

Posted by: moparrob Dec 17 2010, 09:34 PM

If you feel like driving to LA you can try out my new baking soda blaster I assembled last week....

Posted by: Black22 Dec 17 2010, 10:56 PM

Where did you get that and how much was it?

Posted by: moparrob Dec 17 2010, 11:36 PM

See the thread:

http://www.914world.com/bbs2/index.php?showtopic=113747&hl=

The cart was on sale for $30 and the desktop blaster was $119. I added a utility bulb and fixture inside and mounted a bathroom exhaust fan on the back (cuz I had one sitting around).

Posted by: karlo Dec 18 2010, 12:22 AM

Chromium Trioxide is hexavalent chromium and is bad news. It's recognized as a carcinogen and mutagen via inhalation, eg. from welding stainless steel. If you handle it with extreme care, it shouldn't pose a health risk.

I've used it for chromating zinc plated parts, but I'm pretty scared of the stuff. If you don't have to handle the stuff, I'd steer clear.

Posted by: sean_v8_914 Dec 18 2010, 10:13 AM

liquid Satan! I will be cautious.
I dont think I will need to go that radical since my MFI ITBs are not very corroded

Posted by: jd74914 Dec 18 2010, 06:47 PM

Just for anyone reading...I wanted to reiterate that hexavalent chromium is nasty stuff.

If you do use it please be sure to carefully store it and dispose at a hazardous waste facility. To dispose of it you would need to heavily reduce it (with some sulfates, etc) and then neutralize with an acid, both steps of which are way beyond the capabilities of a nonprofessional disposal center.

The reason it is so terrible is that it is highly soluble in water and can easily pollute ground sources if disposed of improperly.

Posted by: ONTHEGRIND Dec 18 2010, 07:21 PM

Just Blast it and paint it a mag color our coating supploer make some mage colors..

Posted by: Richard Casto Dec 18 2010, 08:25 PM

Just rent and watch the movie Erin Brockovitch. It's all about hexavalent chromium. Great for Magnesium, but bad for everyone else. It's probably very hard to get and something people should just have around.

Posted by: Richard Casto Dec 18 2010, 08:26 PM

After blasted, how and what was used to prep for paint? What type of paint was used?

Posted by: ONTHEGRIND Dec 18 2010, 09:13 PM

This is for my personal engine so I just used paint but for our customers we use.. Techline coatings.. My stuff is no more the Duplicolor Fan is Cast Iron is the name of the color and the housing is semi gloss black..

First I sand Blasted, Then cleaned with M.e.k I then bake it in the oven for 5 mins at 100 degrees f Spray let air dry for 10 mins the start at 200 degrees for 20 mins with no fan in the oven then increase the heat to 500 with fan on..