Any research on unexpected degradation of aluminum engine components due to vapor blasting?

[Crazy Dirt]

Hi all,
I was looking at adding a vapor blasting setup to the shop; the manufacturers have a lot of selling points they claim. As I was thinking about the benefits of using soda (soft @ only 2.5 mohs, oil absorption qualities, and water soluble) and another listed benefit of the wet process, the ability to reuse the media 4 times, something occurred to me: Has anyone researched the effects of debris (like carbon) contaminating the soda media and thus increasing the content of harder particles in the media the more it is reused?

[travis]

When I worked in a FAA certified plating and machine shop years ago, the wet soda blaster was by far the least used cleaner we had. We didn’t use it for anything other than a final cleaning before plating and on only a few parts..the media is much too soft (and therefore slow) to remove anything other than wax residue or oils from your hands. Wax was used to mask everything you don’t want plated (or destroyed!) on irregular shaped parts. With a 1/8” or so thick layer of wax that had cooled, it would take forever to blast your way through it with the soda blaster.

We only replaced the water/soda media when the smell got bad enough! It always looked brand new when replacing it, but normal bacteria and mildew was a much bigger issue than dirt...but remember, we only used this as a final cleaner before plating. There was multiple cleaning steps before anything ever hit the soda blaster

[Crazy Dirt]

Thank you for weighing in. I didn’t think there would be a bacterial issue with soda. That gives me something else to consider. I have heard of some of the “green cleaners” having that issue as well.

I am looking at the soda as a means to hit the 10% that the hot bath ultrasonic cleaner is slow to remove. Mainly stubborn carbon deposits in places like intake runners, ring grooves, etc. that are shielded from the ultrasonic waves.

Something like a cylinder head is getting a few cycles with some brushing in between to give the ultrasonic some places to get a better bite on. I think they call it improving nucleation sites. I saw some videos of people melting carbon off aluminum parts with soda blasting and it got the thought train rolling.

[modok]

Dry soda blasting
or wet with glass beads.
I don't understand why you would wet blast with soda

[travis]

I couldn’t imagine trying to clean tough carbon deposits with a wet soda blaster. You probably wouldn’t hurt the base metal but you might die of old age before you ever got the baked on carbon removed

For tough deposits we used a dry glass oxide blaster if it was something we couldn’t hit with the sand blaster. The glass oxide is a fine silica powder that leaves a very nice, very smooth finish. You still had to degrease afterwords, and the glass powder didn’t stay clean very long even being constantly filtered. Glass beads leave a rougher finish, especially on aluminum.

One other thing with the wet soda blaster. You need a clean rinse tank and a lot of agitation to really get that stuff out of all the nooks and crannies. If you let it dry on a part it can be a real bugger to get everything clean.

[travis]

Dry soda blasting
or wet with glass beads.
I don't understand why you would wet blast with soda

I honestly couldn’t imagine a wet soda blaster having a place in a automotive machine shop. In the aircraft world, particularly with radials, if the bearing surfaces get worn or beat up, you don’t replace cranks and rods. You hard chrome the bearing surfaces and they are ground back to standard size. For good adhesion with the electro-plating, everything had to be absolutely perfectly clean. Bearings was also not replaced...they was stripped to the base metal and built back up with multiple layers of different platings...copper, lead, indium, and tin, and sometimes cadmium. To clean those big radial crank bearings you would normally use cheese cloth and a pumice powder. Small hard to clean stuff like impeller blades and such, got the soda blaster

[jeremyinlinepro]

I tried wet blasting with soda and it didn’t work at all. It was equal to washing the part in a hot tank. I was trying to cut down on the dust soda creates. I went back to dry soda blasting and sold the vapor hone cabinet.

[Crazy Dirt]

I tried wet blasting with soda and it didn’t work at all. It was equal to washing the part in a hot tank. I was trying to cut down on the dust soda creates. I went back to dry soda blasting and sold the vapor hone cabinet.

Well shoot, that’s not very encouraging to hear. The videos look great but your experience is a good check on their claims.

[Crazy Dirt]

I couldn’t imagine trying to clean tough carbon deposits with a wet soda blaster. You probably wouldn’t hurt the base metal but you might die of old age before you ever got the baked on carbon removed

For tough deposits we used a dry glass oxide blaster if it was something we couldn’t hit with the sand blaster. The glass oxide is a fine silica powder that leaves a very nice, very smooth finish. You still had to degrease afterwords, and the glass powder didn’t stay clean very long even being constantly filtered. Glass beads leave a rougher finish, especially on aluminum.

One other thing with the wet soda blaster. You need a clean rinse tank and a lot of agitation to really get that stuff out of all the nooks and crannies. If you let it dry on a part it can be a real bugger to get everything clean.

Sounds like I will be better off just sticking with the ultrasonic hot tank. It does a pretty good job with the aircraft cleaner in it, and it has the benefit of not needing to be babysat so it’s sort of like having a shop helper I don’t have to pay. Thanks for your experiences with soda.