Soda blasting... not so much...

I soda blasted this corner of the crankcase for two minutes. Other than the light coating of baking soda, I can't tell the difference. (Before on the left, after on the right)

I must be doing something wrong?
HF blast cabinet, 100 psi, 9 cfm, 1/8" tip, Armex baking soda (maintenance formula).

Tips?

 

In my experience, that's all soda blasting will do on a case. It's a pretty gentle cleaning method. The best attribute of soda is that it will dissolve so you don't have to worry about glass beads or sand in the wrong place.

For those tight places, a Dremel and wire brushes works pretty good.

 

I'm hesitant to use glass bead exactly for that reason. However, it's looking like I'm going to have to. Although it's probably not necessary, as I'm not going to be polishing the aluminum. I plan on painting it.

 

I'm not positive on this but aren't the cases coated in an epoxy type paint? Could paint stripper be an option in cleaning that up?

As to beat blasting I've had it done on a set of cylinder heads and they looked so good that all I did was shoot some clear on them.

 

I tried (HF) glass bead, it definitely gave a uniform finish. Although a rather rough finish. I suspect this is more like crushed glass than bead. I'll just have to be extra thorough when cleaning them before paint and assembly.

(Before and after)

 

The cylinder heads that I mentioned where white after glass beading, even whiter than I could have gotten out of a rattle can which is why I chose to just clear over them.

 

Have you tried walnut shell media? Supposed to be less aggressive than glass, more than soda. I have no experience with it.

 

I got a cheap HF blasting gun for my Compresor and as you see, it was not that great, Especially compared to ultrasonic w/ Simple Green Aircraft cleaner.
We did blast some rusty gardening tools and it worked there but not any more impressive than taking a wire wheel to it. It just allowed us to get into crevices that I would have taken a brush or dremel to.
It WAS good a removing some dirt in some aluminum crevesis though w/o being as abrasive as a wire wheel or coarse brush.

 

The glass bead seemed to do pretty good. The finish it left feels about like 320 grit, which is fine, because I'm going to hand sand to 400 before applying primer.

Here are some before and after pics.

 

I did some more blasting.

 

I have the air gun for this but have not tried it yet. Will have to see how it does on reviving some engine looks.

 

I just completed the most important part of the bike...

 

Looks good! In about 19yrs you’ll be done with the whole thing!!

 

18.7 !

 

The best method I've found is vapor blasting. It almost has a self-polishing effect on the aluminum, and doesn't etch the surface as much. Kind of like the finish you get from vibratory tumbling (if you're familiar).
I'm fortunate enough to have some local vapor-blasting companies within a 50-mile radius, and they're not super expensive.
This photo is of the motor from the Bridgestone motorcycle I'm restoring. The others are before and after pics of odds and ends from the same cycle.
For parts that will be painted, I have no hesitation sandblasting them. For visible aluminum parts like these, try vapor blasting.

 

I polished the pistons.