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soda vs walnut shell blasting?

I have a large (MC frame size) blast cabinet with garnet, an outdoor use pressure pot blaster, and a smaller cabinet with walnut shell. IOW, the practice & expectations are not totally alien to me.

My question re: recent soda blast popularity - how does soda blasting compare to coarse walnut shell? E.G. Armand Hammer Armex, since it is sold at HF? Is it any more aggressive or about the same? Purpose is cleaning aluminum engine parts.
 
I haven't used the walnut shell so I can't make the comparison but I use a soda blaster pretty frequently to clean carburetors. It works pretty awesome for me; it's a big time saver.
How abrasive is it ?
I'm used to just glass bead for aluminum.
 
How abrasive is it ?
I'm used to just glass bead for aluminum.

Not very aggressive at all. It produces a finish that is sort of like what you'd get with a very fine, very round glass bead. I actually don't even bother to reclaim the soda either. I use the siphon blaster and blast the carbs outside. Don't have to worry about getting a bunch of grease and oil in my blast cabinet that way.
 
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Doug -
I to try tp avoid using glass beads on engine parts.
Not saying "never" yet.
I know most of the world does, but not doing it everyday, it's just one more nuisance that the time masking and triple/quadruple cleaning just doesn't work for the projects i want to blast.

EKretz- Would soda effectively clean a combustion chamber, say? Or piston crown?

smt
 
Doug -
I to try tp avoid using glass beads on engine parts.
Not saying "never" yet.
I know most of the world does, but not doing it everyday, it's just one more nuisance that the time masking and triple/quadruple cleaning just doesn't work for the projects i want to blast.

EKretz- Would soda effectively clean a combustion chamber, say? Or piston crown?

smt

Stephen, possibly, but probably not very efficiently. It is pretty gentle and in my experience some of that baked-on carbon can be like glass.
 
As others said, its very gentle possibly the most gentle of any abrasive I've used. Yes it will clean internal engine parts but you may need some brake clean prior. It's a finish type process, I use it before machining heads. It will not damage porous cast aluminum, but may not get super bad area's perfectly clean. If you try it, you'll likely keep a few bags around, its handy.
 
Thanks, guys.
The HF guy said i can't just clean out the walnut cabinet and pour in soda - has to be run in a pressure pot? My SKAT pressure pot is pretty contaminated with #2 quartsite & some black beauty from the bad 'ol days as is the big cabinet which now has garnet in it. Seemed like a lot of effort for unknown results? So i bought a bunch of wire brushes and will just grit my teeth instead of the castings and go at it.

I tried walnut media once, did not seem to do much at all. What is the proper use for walnut blasting media?

Not sure myself.
I bought 50 lbs "coarse" a few decades ago and then never used it because of the effort to clean out the other equipment. Last week bought the small unit to dedicate for "gentle" use (walnut, plastic, or?). It is certainly gentle. So far it is good for getting under and blowing off relatively poorly bonded solid crud and loose paint. It is not aggressive. OTOH I need to add a shaker to the cabinet. (Blast, kick, blast, kick......)

smt
 
Check into Urea and Melamine( a little more aggressive ) media. Strips paint, powder coating, carbon. Pretty much harmless to the metal base material. The Urea doesn't to a thing to machined surfaces. Very low dust levels. Really happy with it. Just discovered it recently, but it's been used in the aerospace industry for some time.
 
Thanks, guys.
The HF guy said i can't just clean out the walnut cabinet and pour in soda - has to be run in a pressure pot? My SKAT pressure pot is pretty contaminated with #2 quartsite & some black beauty from the bad 'ol days as is the big cabinet which now has garnet in it. Seemed like a lot of effort for unknown results? So i bought a bunch of wire brushes and will just grit my teeth instead of the castings and go at it.



Not sure myself.
I bought 50 lbs "coarse" a few decades ago and then never used it because of the effort to clean out the other equipment. Last week bought the small unit to dedicate for "gentle" use (walnut, plastic, or?). It is certainly gentle. So far it is good for getting under and blowing off relatively poorly bonded solid crud and loose paint. It is not aggressive. OTOH I need to add a shaker to the cabinet. (Blast, kick, blast, kick......)

smt
I added a small air powered vibrator to mine, tee'd it off the foot pedal.
The small kind with a ball bearing that spins around inside.

The soda is very small particle size, and will get in all the tiny casting marks to clean properly.
Walnut. plastic will not so much.

I will suggest tee'ing off the foot pedal a small amount of air (put in a simple 1/4" needle valve) and place a hose at the bottom of the hopper to agitate and bubble up thru the soda. Might even try a aquarium bubbler "stone".
 
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The best attribute to soda blasting is it is guaranteed to wash off and not embed or contaminate threaded holes.

Most production engine shops have had to step up to ultrasonic tanks to clean aluminum cylinder heads.

jack vines
 
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Per some of my questions, this might help others. sort of.
I don't know how to extract the chart & can't find it on the Skat homepages.

If you scroll down in this eBay ad, near the bottom there is a chart listing comparative times for a given task among all the typical abrasives. Walnut is pretty lame. :) Soda looks much better. Plastic better yet.


Trying to order melamine for Aircraft Spruce per akjeff's link.
Customer service is researching to get back to me re: is T3 capable of rounding machined Al casting edges? I'm ok if it will, might even prefer it. But info would be useful to decsion between T2/T3.
 
akjeff- are you using the T2 or T3?
I'm inclined to T3 ("our most aggressive fast blast media") if as you say, it is pretty innocuous to machined surfaces.
Thanks for that link!
smt
Hi Stephan,

I have/use both the T2 and T3. The T2 is pretty much harmless to both aluminum and steel. The T3 is noticeably more aggressive, and will soften the edges of, and give that "frosted" appearance on aluminum, but is still gentle on steel. As a test, I taped up half of a piston wrist pin, and hit it with the T3. Took the tape off, and you couldn't tell which half was which.
 
Just used the T3 this morning to clean up the crusty bottom of a Walker chuck that came on a Harig grinder project that was recently gifted to me. While it didn't get it shiny clean it is smooth enough to stone, and in good enough shape to re-grind now. 5-10 minutes in the blast cabinet, saved a hell of a lot of time spent doing the WD40 & razor blade routine. The hold down clamps and hardware cleaned up really nicely. I taped off the chuck with Gorilla tape, and the only exposed surface was the bottom.

Before
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After
IMG_0298.JPG
IMG_0297.JPG
 








 
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