Aluminum Part Original Finish Questions

[RamAirBirds]

Doing some Vapor Honing with a local place here....
What is the feeling about original finish / shade for the following Aluminum Parts..
Muncie Trans Case/Tail
Bell Housing
Chevy / Pontiac Aluminum Intake
Alternator
Distributor
All of these must have been cast with possibly different Aluminum compositions....I guess....But would they all have the same "SHEEN".
I feel I have seen nice original Bell Housings that appear more "shiny / polished that the other parts.
I feel I have seen original Alternators and may distributors that are "Darker" than Muncies or Intakes etc...
Many people are moving towards Vapor Honing for Finish and my firsthand experience is very positive with the outcome. Media Size and such can deliver different results. Trying to get some real info...ANY INPUT IS WELCOME...This Thread may serve to help others down the road.....
Thanks SCR Community for any thoughts or examples.....

[CamarosRus]

I have zero experience with vapor honing

I do have experience seeing Aluminum Sand Casted Intakes that were Metal Shot Blasted
as they were when mfg at a Foundry


See my alternator cases that were tumbled/shaken in ceramic media..........

Ive also shot blasted Muncie Case (Sand casting) and Tumbled/Shaken Muncie
Tailhousing, Side Cover

[mhm1966]

Do some research on vapor blasting. I am not sure if it's the same as vapor honing.

[RamAirBirds]

Yes this is Vapor Honing. Meant to restore the surface not so much for cleaning.

[Kurt S]

It matters if it's a diecast part or a sand cast part, very different finishes.
Most smaller parts are diecast and will have a smoother finish (because they were cast in a steel mold).
The trans maincase was a sand cast part.

[RamAirBirds]

yes Kurt, makes a lot of sense. The Bell Housing should be sand cast but many originals look almost polished...

[big gear head]

I may be wrong, but I believe bell housings are die cast. Heads, intake manifolds and Muncie main cases are sand cast.

[turbo69bird]

I have my own vapor blaster and I can vary the finish.
Sometimes I get a part the way I want it and later I decide I want it just a little less shiny or it’s too dull and I bring it up w a differnt mix or even different amounts of air pressure.

These pictures are from when I first started and I was playing with parts to get the right sheen.
Gives a good idea of the differences.
Trans case is just cleaned vs vapor blasted.

RAIV intake was dull after being, just cleaned vapor blasted half in first pic and then Finished.

[turbo69bird]

Notice it doesn’t smooth out any of the rough casting, it won’t even remove anything silicone. If I need to remove paint I glass bead it first gently to remove the paint then I bring the finish back up w the vapor (honing) blasting. I don’t think there’s any difference between vapor honing and vapor blasting at least not as far as I know. It’s all media in water. Some people add glycol to the mix.

The whole point of it is to roll the media across the finish which closes the surface vs striking the surface and abrading it with some mixes I could polish it like chrome.

[jl8z28]

Personally i think the vapor blasting is to shiny

[RamAirBirds]

Like Turbo69bird mentioned. The level of shiny vs dull is calibrated by the size of the media along with pressure. I have done many trans cases so far and the look is great. I do see the (Tumbled in shot) examples but it appears that has Made the case a little rougher than when it started. The Vapor Blast/Hone is surface recon only....does not tear open the casting pores like Sand or Glass does. Best to start with a clean part before the Vapor process.
I have many parts that were blasted with walnut for cleaning and then to Vapor. If it's too shiny the bead size of pressure needs adjust. Even if it comes out to shiny just go back over once set up right.
Thanks for everyones comments / thoughts...

[BCreekDave]

'837 alternator case before-after nitric acid "desmutting" soak. Not too bright, just clean and aluminum oxide tarnish removed

[turbo69bird]

Like I say you can vary the finish to whatever you want. So it can’t be too shiny it can only be that the operator is making it too shiny . When I did that RAIV intake I did it to match a NOS factory intake. You can make it as dull or as shiny as you want if you know how to vary it
Most people are basing what they think is correct on very old pieces that no matter how well kept have dulled to some extent
I was amazed at just how much sheen that NOS in the box intake actually had in comparison to what I expected . .

[turbo69bird]

That trans case had been dipped and they couldn’t get the black specs out of it no matter what they did. It took a lot of work but I was able to get it right w the Vapor blaster

Took me about 5 hours to get it right certainly wasn’t a money maker by any means.
In fact IMO vapor blasting isn’t a fast low labor solution. Takes a long time and a lot work to get it right. There’s alot of angles and I’m constantly pulling the part out washing it, inspecting it and putting it back in to get it right

I don’t want to do any more to a part than I need to, but I also don’t want it unfinished. You just can’t tell while it’s in being done.

Idk how anyone could ever make money doing vapor blasting for a living.