Case finish - Sodablast/Beadblast

[OldHog66]

Need some case and shovel rocker cover (and primary cover) finishing advice.
I read in the AMCA magazine that soda blasting was just the ticket for the case.

I bought a (admittedly inexpensive) handheld gun with a storage canister built in. Shot soda media at 100 psi and had pretty dismal results. meaning it really didn't get the "old" off the finish. The gun was only "rated" for 90psi surely was designed for sandblast (not soda blast).

My need now is "what is the best/easiest way to finish a case". I have the case halves and all the other aluminum parts ready.

I don't know of anyone that is set up for soda blasting in my vicinity. lots of bead blasters... and I bought some StrongArm spray yesterday, (which they claim will make the aluminum look brand spankin' new again).

Looking for a restoration style finish and not a polished finish on the parts that were not polished.

Does bead blasting give the desired results? Should I look for a commercial soda blaster...does StrongArm sprays do what they claim?


All advice appreciated!!

Thanks
OldHog66
Steve

[Robert Luland]

Might want to take it to your local tranny shop and let them dip it in the soup. Or as I call it . The poor mans glass beader. Bob

[OldHog66]

Bob,
forgive my ignorance, but what is the soup and what does it do?

Steve

[bmh]

My local non-authorized H-D spead freak machine shop blasts stuff like this with a plastic media made of ground up detergent bottles. Have had them do stuff for me and was amazed, they removed old cooked and shellaced on gaskets without damaging the milling marks in the aluminum underneath. they use a standard cabinet, but I don't know where they get the stuff or what nozzle and pressure they use. They do say the media loses it's bite pretty quick and needs frequent replacement.

[OldHog66]

Thanks Brian,
I was thinking about media blasting but didn't know if it was a possibility. Media blasters are everywhere, unlike soda blasters.

Steve

[rousseau]

Has any one seen or heard of "vapor blasting" ? It seems as if they mix the soda or beads with a liquid cleaner. The results look great in the few pictures i've seen. I googled it ,but looks to only be in The UK. My quess is the E.P.A. probably won't allow it here.

[Kozy]

I've had aluminum cases soda blasted by an industrial painting contractor. I think their process used soda entrained in a water blast.

[Snakeoil]

I don't think you need a special blaster to sodablast. A friend of mine has purchased large boxes of Arm and Hammer soda and just put it in a regular sand blaster. You should not use a blast cabinet because the dust inside pretty much makes it impossible to see what you are doing. He said the soda is turned to dust when it impacts so outside is the best bet and soda is non-toxic. Harbor Freight sells a small blast nozzle with a hopper for something like 14 bucks. That should do the trick. I may try putting some thru my siphon sand blaster when the weather warms up a bit. Might machine a smaller nozzle to keep the flow down a bit.
regards,
Rob

[exeric]

Has glass beading turned toxic or something? I've glass beaded engine cases for years and have been delighted with the results. Of coarse you have to do a carefull cleaning of all parts, but that's what the dishwasher is for when your wife is out. For parts like cam covers and aluminum primary covers, I have glass beaded them and hand finished with various grades of ScotchBrite. The fact is, you will never simulate the original finish. H-D must have subjected engine and trans cases to any number and variety of cleanings. First they had to clean the aluminum casting of all casting sand which could have been via blasting, vibrating, or high pressure caustic blasting. Casting were then machined which required some cleaning process which was less harsh than the first cleaning but still nasty and based on the number of machining operations, there must have been a proceeding cleaning. What I'm getting at is; nobody can say for certain what patina an engine case should have today. Aluminum oxidizes and will change color and general appearance over time. You could look at a current H-D motor but alloys, and finishes change as have the production proceedures at Harley Davidson. You really have to weigh the expedience of getting the job done well at a decent price vesus jerking yourself all over town looking for some ethereal cleaning process that someone says will make your engine cases look like it did in 1939.

[bmh]

Since about 99 or so the factory has been painting all the aluminum drive train castings with a silver paint called appropriately enough "Silver Beadblast". The stuff is really thin and a little tricky to apply, but it keeps that new aluminum look for a long time and is very resistant to staining. This was done to avoid the yellowing that was being caused by cleaning the castings with steel shot. I've used it on newer machines and even toyed with the thought of using it during restoration but have decided against it. I'm with Eric. Glass bead, sanitize and assemble.