Topic: Sandblasting media for aluminum? (Read 10670 times)

HiProfile · « **on:** February 22, 2010, 02:28:54 PM »

What do you guys recommend? I want to remove the corrosion off some engine parts & blocks and leave as original finish as I can. The problem is any interweb knowledge is skewed because everyone always sandblasts just to strip paint off sheetmetal.

I think walnut shell might be the best bet. I've just not seen anyone use it for removing aluminum corrosion. I don't have a cabinet, so I'm fairly limited. I tried baking soda (real crystals, not "arm & hammer" powder), but it didn't do squat. Cleans it nice, but dark corrosion spots remain.

Suggestions? I'd build a cabinet if there was some miracle media for aluminum corrosion that isn't $$$.

Corey · « **Reply #1 on:** February 22, 2010, 03:23:25 PM »

black beauty. end of story.

go to mcmaster. its part NO 33145K37 50lb bag. 14.75 per bag. it cost me 11 bucks for shipping on the 50lb bags.

this is the only media i use, because its the only kind that works.

bigdaddyvtec · « **Reply #2 on:** February 22, 2010, 03:42:47 PM »

Walnutshell

t_cel_t · « **Reply #3 on:** February 22, 2010, 05:19:39 PM »

ive had awesome results with the glass beads

92CXyD · « **Reply #4 on:** February 22, 2010, 05:42:16 PM »

Quote from: bigdaddyvtec on February 22, 2010, 03:42:47 PM

Walnutshell

+1 that is what we use at foundry to clean up aluminum coreboxes. :yes:

bigdaddyvtec · « **Reply #5 on:** February 22, 2010, 05:45:13 PM »

walnutshell is alot less abrasive than glassbeads... Doesnt take as much off..

92CXyD · « **Reply #6 on:** February 22, 2010, 05:50:11 PM »

Quote from: bigdaddyvtec on February 22, 2010, 05:45:13 PM

walnutshell is alot less abrasive than glassbeads... Doesnt take as much off..

Yeah it also depends on if the material was heat treated or not. The alloy aluminum makes a difference too.

I rather pick something less abrasive when work on many different types of Al.

If you are working on just 319 T-6 type material then glass beads would be ok. :yes:

Whitey · « **Reply #7 on:** February 22, 2010, 06:32:13 PM »

I use the same abrasive ass media as I use for steel, I just turn the pressure down and it turns out alright. Here's 40 year old cast aluminum I did:

After some steel wool and clear:

If you care about the exact media I used, I'll let you know tomorrow

HiProfile · « **Reply #8 on:** February 22, 2010, 06:54:57 PM »

Quote from: 92CXyD on February 22, 2010, 05:42:16 PM

Quote from: bigdaddyvtec on February 22, 2010, 03:42:47 PM
Walnutshell

+1 that is what we use at foundry to clean up aluminum coreboxes. :yes:

I was thinking that would be the better method. I've read about black beauty too, but no cabinet...

I've got 2 gsr blocks I want to clean up, and really don't want any etching or deep scratches. They have typical Wisconsin corrosion, that white/yellow/greenish scale. We actually prefer leaky engines here, it keeps them cleaner.

chris · « **Reply #9 on:** February 23, 2010, 12:31:03 AM »

I use the cheap fine shit from harbor frieght to do throttle bodies/manifolds. Been using it for 5+ years. Stuff comes out pretty nice and no pitting etc from it.

PhilStubbs · « **Reply #10 on:** February 23, 2010, 08:28:49 PM »

i always used glass bead myself. i have done a few blocks and heads with it with really good results. i actually use it for all materials, seems to be a good all purpose media

stealthiskey · « **Reply #11 on:** February 24, 2010, 01:17:30 AM »

Glass bead for aluminum. Black Beauty for stripping paint/rust off steel.

http://www.realhomemadeturbo.com/forum/index.php?topic=1529.0

Quote from: stealthiskey on April 08, 2009, 11:32:08 PM

Before:

After:

HiProfile · « **Reply #12 on:** February 24, 2010, 03:22:31 AM »

Well it's just that people tell me that the breaking beads leave a rough surface on the aluminum. Even the very fine beads. Now that I think of it, the corroded areas are probably just as etched as glass beads could make it. Maybe I'll just do that then buff it out or paint it.

The cool thing is I talked to an old friend who's done practically everything (old guy with crx project). He told me about this U-blast place in Milwaukee where you pay them time to use their blast booths and media while you do the work. Maybe not cheaper, but much faster than building a booth I'd have to tear apart after a few days.

Speaking of beads....

http://youporn.com/watch/357091/anal-bead-amateur/?pos=1

(couldn't find anything but anal beads)

stealthiskey · « **Reply #13 on:** February 24, 2010, 10:35:21 AM »

i dont know if id say they leave a "rough" surface. The do leave a surface though, which is actually how they work so well at removing aluminum oxide. Al oxide is a hard brittle material, but only a few microns thick, the impact of the beads breaks it up and it chips it off, but really doesn't remove a measurable amount of material.

I'm certain walnutshell would leave a smoother finish as its softer media, but I don't know if it would be able to break up the oxide well. Also, adjusting air pressure gives you a wide range of results for any specific media.

Lastly, I can't think of an aluminum engine part I would be worried about hitting with glass beads. Certainly anything cast will not get any rougher, and anything machined ... I don't think the tolerances would be altered any just the surface texture.

t_cel_t · « **Reply #14 on:** February 24, 2010, 12:18:25 PM »

the glass beads are perfect for aluminum, it doesnt damage the aluminum at all. sand on the other hand will eat into steel.

PhilStubbs · « **Reply #15 on:** February 24, 2010, 01:09:08 PM »

I have used glass bead to clean gasket surfaces and never had leaks. It leaves a nice matte finish. I really have never seen any issues other than thin sheet aluminum

HiProfile · « **Reply #16 on:** February 24, 2010, 05:32:01 PM »

Well I guess I'm going to look into either building a temp cabinet & getting some beads, or going to that u-blast place.

Now I'm just worried about shit remaining inside the crankcase & oil passages. I'm going to tape & plug every hole on these suckers up like they were double-D asian twins. ;D

kgx · « **Reply #17 on:** February 24, 2010, 06:04:58 PM »

+1 for glass bead. i've also had luck on really heavily oxidized pieces using lye to scrub off much of the corrosion, then blasting to even out the surface.

Foowee · « **Reply #18 on:** February 24, 2010, 08:10:34 PM »

I heard something about dryice blasting recently... supposedly doesn't etch or work the metal at all while removing stains n debris... I haven't done it myself, but it may be worth looking into. You don't need a cabinet cause the dryice evaporates and leaves the debis on the ground. No media to cleanup.

snm95ls · « **Reply #19 on:** February 24, 2010, 08:33:43 PM »

This thread inspired me to buy some black beauty.

Goon have to try it out this weekend methinks.

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Author Topic: Sandblasting media for aluminum? (Read 10670 times)

chris