Soda, Walnut, or Glass Bead Blasting?

I am about ready to put my engine back together but am not happy with the finish. I am also lazy and don't want to put in the time to polish the head, cylinders, cases and covers by hand. So I am left with the various media blasting options. Soda blasting looks good for a restored look, but I wonder if it is aggressive enough to remove the 30 years worth of corrosion. The soda blast guy tells me that the engine will look like new. There is no major pitting or anything like that, but under close inspection there are dark marks that look like light corrosion. Walnut shell blasting might be a step up in the hardness scale of blasting media. Then there is glass bead blasting, but I wonder if that would give the engine a "beyond original shine" look. Any experience or comments on these three options? Thanks for your input.

You'd probably better stick with soda if you don't wanna do a lot of work.

I use silica media and it cuts like a knife; but I want the surface prepped for poweder-coating (or whatever) b/c I like my motors black. If you went with the silica media it'd sure cut everyting off, but you'd have work to do after that. But, if you wanted, then you could take scotch-brite to it and get that 'brushed' / 'machined' look and then put a light clear coat over it to keep it that way. Just a thought.

Post up pics of your progress and your results!

-KR

Post edited by: Bad Kaw, at: 2008/01/29 22:01

There has been a lot of discussion about the residue left behind by walnut shell blasting on other sites, apparently it's a real bear to remove and has caused some serious problems in certain situations.

I agree about the walnut shells leaving plenty of dust and the like - but they work well... they do not remove any metal - I think the glass bead leaves the metal too bright - a sign metal is being removed. I have experimented with different size glass bead, walney shells and some other stuff - but still use the walnut shell media on engine cases.

The biggest issue with the walnut shells is a tendancy to clog the pickup tube in my blast cabinet due to the larger size - so I now have a modified pickup tube at the bottom of the cabinet with two pickup holes - I close off one of the two depending on the media.

Also, I have to run 100 psi with the walnut shells and the poor compressor is running flat out all the time - whereas for most glass bead, I wind the air pressure down to around 65 or 70 psi.

Soda. Walnut shells are too slow. Grit embeds itself in aluminum. Soda washes away with water. I buy 12 lb. bags at Sam's club for $5. It's between the walnut shells and aluminum oxide as far as how fast it cuts. But you make up for it without spending so long blowing the grit out of all the nooks and crannies.

-Jim Bateman

I figured the soda to be a softer and slower media than walnut shells. How does it do on the corrosion? Are you using any special equipment to spray the soda?