Aluminum intake restoration ...re-re-re-visited

[Irby G.]

I know this has been beaten to death here but please bear with me and do the link:
Doing a little research and I ran into this web site. Apparently, a GM design engineer states that sand cast aluminum hasn't got a 'skin' same as a die cast gives aluminum that forms against a permanent cooled mold, allowing it to be clean as it was originally (steel shot blasted). My first question is, does this hold water with you guys 'in the know'? Secondly, if so, how do you tell sand cast from die cast?
Read further down, post by mrrec. Interesting post to say the least.




Aluminum restoration post from Super Car Registry

[William C.]

Re: Aluminum intake restoration ...re-re-re-visite

Sand cast parts will generally have a rougher texture than die cast, look at the examples of the trans main case and the trans side cover. The side cover (and Tailhousing) are die cast, while the main case and intake manifold are sand cast. There is a significant difference in the texture of the finish.

[Bryan L.]

Re: Aluminum intake restoration ...re-re-re-visite

Everybody poopoos sand blasting but that's what I did on my tripower intake. I used medium grit sand at about 40 psi from a couple of feet away and did just enough to clean it up. I then used OEM Protect aluminum spray that I got from ASL a few years ago and sprayed it on and wiped off the excess. It's beautiful. I also did this on a 69 Z/28 intake on a friend's L-79 intake, and on Muncie cases with similar results.

I've also used bead blasting on alum intakes going on hot rods but I don't like the look. IMO the sand gives a finish that looks more original than the glass beads. I'm curious about how the phosphoric and nitric acid dips look. Might have to give it a try next time. The parts that were blasted with the steel shot look outstanding.

BL

[Clare Carpenter]

Try walnut shell media

On the GTO resto Dream Car Garage is doing on the Speed Channel, they used walnut shell media to clean up the Muncie case. They do top notch work with no shortcuts and claim the process makes cast aluminum look brand new.