Restoring Cast Aluminum

[Chicken Coupe]

Bead/sand blasting will clean the surface up fast, but it 'opens' the surface. It will deteriorate almost as fast as it was cleaned.

Soda blasting is gentler. It will not open the surface, but it also does not take off 'embedded' discoloration. You could use a cheap plunge supply blaster, a compressor, and a 5 lb bag from a Costco-like store.

IF YOU DO, MAKE SURE YOU ARE WEARING A HIGH QUALITY RESPIRATOR!

If you can't blast, there's only 2 real good ways to clean an aluminum intake.

Edelbrock recommends a brand of liquid rust dissolver.

I tried using Eastwoods, version that I had sitting around with excellent results. I 'assisted' the process with a toothbrush sized stainless steel brush. You have to soak, brush, soak, brush, etc.

A part of the directions of the liquid dissolver is to keep a steady wash moving over the area. I did it with about a 1/2 gal of the cleaner in a plastic storage box that was big enough for the intake to fit it, using a small submersible pump that I picked up at Harbor freight

It got back to 98% of it's original look. You can see some remaining dark discoloration/stains that I didn't fully address as I was planning to use it as a "cover" for my new motor, but went with a 67 tri-power intake. With a bit more effort, it would have been 'new'.

Just remember, this intake is 40 years old and was as grungy and discolored as it could get.





Before starting, the best method to clean is to wash down throughly with a few cans of brake clean. DO NOT use a water based cleaner concentrate. They oxidize the alum QUICKLY, making the whole process harder.

Next method is to send it out to be 're-skinned'. That process is used by restorers to reproduce the original 'as-cast' finish. I'm not 100% sure what they do to get the metal down to 'spotless', but the final step is to put the manifold into an oversize tumbler with rubberized abrasive beads. This process "closes" the pores that were put there from blasting or were left from casting, by 'wearing down' the surface. Here's a before and after of the 67 manifold.











This is the heat riser passage. It was choked with exhaust carbon when I sent it out.



The ONLY recommended method to keep it looking good is to spray with brake clean and wipe with a clean, absorbent, lint-free cloth (like a cloth baby diaper or layered cheese cloth)

The company I used to refinish and repair the intake was http://www.z28camaro.com/restosvcs.html