got a set of valve covers that have been polished. I regret that they were done. originally, they had a neat, dull finish. they are die cast finned aluminum covers from 1971. I want to get rid of the polished look, and get that nice dull, die-cast aluminum back.
any ideas?
want something that looks like this: http://www.budind.com/images/product/large/die-cast-aluminum-enclosure-n4-mmb.jpg
Bead blast with the finest grit you can find. Maybe even walnut shells.
Or just leave them outside for a few days?
Bead blast it.
Scotchbrite and elbow grease? That will be a bit raw and bright, but give it time after that and it will dullen up to your desired finish.
I remember some where we did this with a solution of muriatic acid and water but it was so long ago I don't remember the amounts. I remember that the pieces went in all shiny and new and came back looking like the cast alu pieces you see on race motors from the 60's and 70's
This one is in my wheelhouse.
Media blasting will always look media blasted. There is no way to make it nice an uniform looking and it will always have stripes like a rattle can job. It will also oil stain, and stain differently in different areas depending on how much or little it required blasting.
I use a large abrasive media tumbler. Toss the parts in and fish them out in an hour or so. This is for concourse style restos. Everyone asks us how we make castings look so correct.
If you are willing to ship your valve covers to me I can do this for you. It is almost zero labor.
In reply to Jumper K. Balls:
And it'll look like the old 60s/70s die cast aluminum race car parts they are? If so, I'm game!
It easier then you think. Castrol super clean. will turn polished bright to dull gray white spray on keep wet let dry then rinse. Ospho can work too but it more the other way take dull diamond plate back to bright.
These alfa cam covers were polished and the owner wanted a stock look.
Yours would turn out pretty much like these.
Got a pic of the fins? the media is almost 1/4" so it wont fit into really tight spaces.
that alfa valve cover is just what im looking for. what do we do to keep it that way?
heres what we're starting with.
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I've found that glass bead blasting gives a good "cast" look to aluminum. It leaves a smooth finish that has a "semi-gloss" shine to it that to me looks like a new cast aluminum finish.
If they are bead blasted, coat them in a satin or flat clear. It will keep them from staining.
I did these with aluminum paint. Think they look great, but I'm biased.
Glass beading or grit blasting works best but will start to corrode quickly that is what protects to aluminum from further corrosion. If you beat/grit blast you need to cover lightly with a clear coat. Sometimes Eagle 1 magnesium and aluminum wheel cleaner and etch will restore the brightness of the aluminum. They sell it at Advance Auto and probably other places also. Be sure to wear some rubber gloves and eye protection and try not to breathe the fumes as the stuff is pretty intense.
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