Author Topic: Removing blackist mottled discolored on engine cases.  (Read 1089 times)

Offline gearman

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Removing blackist mottled discolored on engine cases.
« on: August 06, 2017, 12:29:41 PM »
77 convert,I don't want to glass bead the cases but have any of you found a chemical that would remove or lessen the the  staining. I have used Trailer brightener in the past but it strips the zinc off of the fasteners.I think it was phosforic acid.SP.Thanks all.

canuck750

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Re: Removing blackist mottled discolored on engine cases.
« Reply #1 on: August 06, 2017, 09:35:33 PM »
I think any acid will remove the zinc plating on fasteners. You could try soda boasting, pretty effective but slow work.

Online nc43bsa

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Re: Removing blackist mottled discolored on engine cases.
« Reply #2 on: August 06, 2017, 09:38:31 PM »
Or you could clean the cases as well as you can and spray them with cast aluminum paint.

I did that on my rear drive and rear wheel hub.
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Offline blackcat

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Re: Removing blackist mottled discolored on engine cases.
« Reply #3 on: August 07, 2017, 07:09:03 AM »
I found a guy who has a large mobile soda blasting setup who usually does whole cars for restoration, and he has shot the engine, transmission and final drive for something like $75 bucks. Well worth the money and all were blasted completely clean.
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Re: Removing blackist mottled discolored on engine cases.
« Reply #3 on: August 07, 2017, 07:09:03 AM »

Offline Sheepdog

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Re: Removing blackist mottled discolored on engine cases.
« Reply #4 on: August 07, 2017, 10:13:41 AM »
I use WD40 and 0000 steel wool on dirty aluminum cases. Four-aught wool is fine enough that no scratches will show. The WD40 is a solvent that is mild, but complements the steel wool well. In addition, the WD40 leaves a film that protects the aluminum and makes future cleanups easier.

If that doesn't work, soda-blasting will do the job. Baking soda is a great media for aluminum as it is mild-yet-effective and the residue will dissolve with a little water.
« Last Edit: August 07, 2017, 10:17:03 AM by Sheepdog »
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Offline Antietam Classic Cycle

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Re: Removing blackist mottled discolored on engine cases.
« Reply #5 on: August 07, 2017, 11:01:34 AM »
Use the aluminum brightener/trailer cleaner and replace the fasteners? If they're the originals, they're about as hard as lead anyway...
Charlie

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