Any Tips For Brightening Cast Aluminum (SU carb bodies)?

Dan Sarandrea (Phila)

Waitin' On Parts...
Helping a friend refurbish a twin carb setup originally on an MG.

Ran all the non-perishable parts thru an ultrasonic bath, so all the dirt is gone but the appearance is dull and humans like shiny, not dull. Other than the bells, we do not relish the thought of polishing all the nooks and crannies with an aluminum cream polish!

I read where a hot bath in household vinegar yields pretty good appearance results. What say you?

EDIT: I can report that a hot vinegar bath does nothing.
 
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andreav

True Classic
I think without fine blasting there are no solutions to returne shinly silver color of aluminum.
 

Dr.Jeff

True Classic
I've experimented with every possible technique I could find on the internet. Most actually made it worse, and almost none really worked any. As @andreav said, media blasting is the only approach that I think works if you want to maintain the actual aluminum finish. There are several types of media blasting that can be done, including some DIY methods. But coating them like @fastx19 suggested will also look great, and keep it looking great longer.
 

PaulD

Paul Davock
I've experimented with every possible technique I could find on the internet. Most actually made it worse, and almost none really worked any. As @andreav said, media blasting is the only approach that I think works if you want to maintain the actual aluminum finish. There are several types of media blasting that can be done, including some DIY methods. But coating them like @fastx19 suggested will also look great, and keep it looking great longer.

I have been using very fine soft wire wheel. Close to shiny and it can get into corers and edges. Press too hard and it will round edges. This thermostat housing was done that way:

DSC_0400.jpg


Wait! on second thought I think I glass blasted it, I will look for one with my throttle bodies.

My apoligies, I do not have a good picture, as they reside under the upper frame rail.

The second one is of the back of them, look on the lower left side, and and the first one is on the dino where you can get a peak of one under the cold air intake hose on the right:

DSC_0428.jpg
DSC_0524.jpg
 
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Chaostoy

Daily Driver
I read a post years ago somewhere which said to use an air siphon gun (air gun with hose on it) and baking soda for really nice results. It's worth a try.
 

Dr.Jeff

True Classic
I read a post years ago somewhere which said to use an air siphon gun (air gun with hose on it) and baking soda for really nice results. It's worth a try.
Yes, I found good results with soda blasting (almost the same as baking soda) on aluminum. I used a pressure pot type blaster; you cannot reuse soda so a blast cabinet won't work very well. It's messy but it won't hurt the aluminum and leaves a good finish. Glass beads also worked well. I didn't try walnut shells but I hear it works very good.

If you are doing something very small and in decent condition then you might get away with the simple siphon gun approach that @Chaostoy described:
6.JPG
 

Chaostoy

Daily Driver
Ya know, I think it was Dr.Jeff's post I was thinking of, because that's the same photo and word for word what I read! Must have been on the yahoo group.
 

Dr.Jeff

True Classic
Ya know, I think it was Dr.Jeff's post I was thinking of, because that's the same photo and word for word what I read! Must have been on the yahoo group.
I don't remember where I first saw that a long time ago, but I saved the picture for future reference. I think we may have talked about the same thing in the past here, and I might have posted the same pic then. Perhaps that's where you've seen it. ;)

When I did some soda blasting I first tried a little regular "baking soda" to test it out. It looked promising so I bought a big bag of "blasting soda". The blasting soda did a much better job than baking soda. Although they are the same material, baking soda is finer and 'softer' so it doesn't clean as effectively as blasting soda. As noted earlier I used a large "pressure pot" style blaster. Judging from my experience with it, I imagine the homebuilt hand airgun version would be quite slow - only cleaning a very small spot as it goes. That's why I say it might work for a small item that doesn't require a lot of cleaning. I used the soda blaster on a engine head to remove the carbon buildup in the chambers and ports, scale in the water passages (as much as can be accessed this way), and general cleanup. I can't imagine trying to do that whole job with the smaller gun. So it may depend what you intend to use it on. :)
 

Dr.Jeff

True Classic
It's kind of interesting, outside of America the term "vapor blasting" seems more common while here it is usually referred to a "wet blasting" or "dustless blasting". Same process, same equipment, same materials. Basically combining water with the blast media. But I've seen a few places here that like to call it "vapor blasting" because that sounds different, and therefore charge more for it. Smart marketing I suppose.
 

Dan Sarandrea (Phila)

Waitin' On Parts...
It's kind of interesting, outside of America the term "vapor blasting" seems more common while here it is usually referred to a "wet blasting" or "dustless blasting". Same process, same equipment, same materials. Basically combining water with the blast media. But I've seen a few places here that like to call it "vapor blasting" because that sounds different, and therefore charge more for it. Smart marketing I suppose.
My understanding of "real" vapor blasting is that it is blasting with dry ice. The sublimation of the solid CO2 as it goes from solid to gas (vapor) is what does the cleaning. The fact that there is no liquid involved is a feature that allows this process to be used on materials sensitive to liquid such as energized electrics and electronics.
 

beezee

True Classic
It's kind of interesting, outside of America the term "vapor blasting" seems more common while here it is usually referred to a "wet blasting" or "dustless blasting". Same process, same equipment, same materials. Basically combining water with the blast media. But I've seen a few places here that like to call it "vapor blasting" because that sounds different, and therefore charge more for it. Smart marketing I suppose.
Actually, outside of the USA it’s known as “vapour“ blasting.

Brian
 

Dr.Jeff

True Classic
My understanding of "real" vapor blasting is that it is blasting with dry ice. The sublimation of the solid CO2 as it goes from solid to gas (vapor) is what does the cleaning. The fact that there is no liquid involved is a feature that allows this process to be used on materials sensitive to liquid such as energized electrics and electronics.
That's what I thought also. But when I researched it I found otherwise. However there may be more than one use of the term with different techniques (i.e. marketing)? Or the information I got was incorrect. Although one of my sources was a company that sells "vapor blasting" equipment in the US. They were at a trade show and I had a chat with them to learn more. According to them the use of dry ice is a totally different thing with different equipment. But who knows.

Maybe that's the difference between "vapor" and "vapour"....as @beezee points out. :p
 

PaulD

Paul Davock
That's what I thought also. But when I researched it I found otherwise. However there may be more than one use of the term with different techniques (i.e. marketing)? Or the information I got was incorrect. Although one of my sources was a company that sells "vapor blasting" equipment in the US. They were at a trade show and I had a chat with them to learn more. According to them the use of dry ice is a totally different thing with different equipment. But who knows.

Maybe that's the difference between "vapor" and "vapour"....as @beezee points out. :p
On time I tried dry ice blasting on a transmission case. It got off all of the dirt and none of the stains. The nylon cap on the breather got cold enough to shatter.
 

Dr.Jeff

True Classic
On a totally unrelated note, I tried using dry ice for another task when restoring a old car.

Removing the factory insulation material on the interior floor boards can be difficult. It is old, brittle, and permanently adhered to the floor. So it tends to come off in tiny bits, like trying to chisel a concrete wall away with a screwdriver. According to the wisdom of the internet the "easy" approach is to cover the insulation with dry ice, let it freeze, then smack it with a hammer. Supposedly it shatters and comes off in big chunks with no cleanup needed. Well it did not work at all for me. And I mean it did absolutely nothing. Perhaps the hot climate here is too much to allow the material to freeze even when buried in dry ice?
 

PaulD

Paul Davock
On a totally unrelated note, I tried using dry ice for another task when restoring a old car.

Removing the factory insulation material on the interior floor boards can be difficult. It is old, brittle, and permanently adhered to the floor. So it tends to come off in tiny bits, like trying to chisel a concrete wall away with a screwdriver. According to the wisdom of the internet the "easy" approach is to cover the insulation with dry ice, let it freeze, then smack it with a hammer. Supposedly it shatters and comes off in big chunks with no cleanup needed. Well it did not work at all for me. And I mean it did absolutely nothing. Perhaps the hot climate here is too much to allow the material to freeze even when buried in dry ice?
I tried it on the floor of my X, breaking the dry ice into small bits, spread it on the insulation on the floor, waited a bit, and gave it a couple of bops from underneath with a rubber mallet. Presto! It all broke off in chunks.
 

Dr.Jeff

True Classic
I tried it on the floor of my X, breaking the dry ice into small bits, spread it on the insulation on the floor, waited a bit, and gave it a couple of bops from underneath with a rubber mallet. Presto! It all broke off in chunks.
I think the climate is just too hot here for it to freeze the insulation enough to work. I suppose if I'd done it in the middle of winter when it actually gets pretty cold here it might have worked better.
 

MikeHynes

True Classic
I think the climate is just too hot here for it to freeze the insulation enough to work. I suppose if I'd done it in the middle of winter when it actually gets pretty cold here it might have worked better.
Here in the midwest it gets hot enough to push the windshield out with your feet in the summer, and cold enough in the winter to bust the asphalt off the bottom of the floors in large chunks. You just have to do a little planning and wait for the right day.
 
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