Author Topic: Removing blackist mottled discolored on engine cases.  (Read 1365 times)

Offline gearman

  • Gaggle Hero
  • *****
  • Posts: 2924
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

  • Guest
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

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 1353
  • Location: Mooresville NC
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.
1990 MilleGT

Offline blackcat

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 8854
  • Location: USA
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.
1968 Norton Fastback
1976 Lemans
1981 CX-100
1993 1000S
1997 Daytona RS
2007 Red Norge

Wildguzzi.com

Re: Removing blackist mottled discolored on engine cases.
« Reply #3 on: August 07, 2017, 07:09:03 AM »

Offline Sheepdog

  • Gaggle Hero
  • *****
  • Posts: 5575
  • 2007 Moto Guzzi California Vintage
  • Location: Waldheim, Louisiana. USA
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 »
"Change is inevitable. Growth is optional." John C. Maxwell

Offline Antietam Classic Cycle

  • Gaggle Hero
  • *****
  • *
  • Posts: 14141
  • Happily stuck in the past.
    • Antietam Classic Cycle
  • Location: Rohrersville, Maryland
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

 

***Wildguzzi Official Logo High Quality 5 Color Window Decals Back In Stock***
Shipping in USA Only. Awesome quality. Back by popular demand. All proceeds go back into the forum.
http://www.wildguzzi.com/Products/products.htm
Advertise Here