Gearbox Case Soda-Blasted
 

My gearbox is off to Gary Fairbanks soon, so I wanted to de-crud the exterior of the case prior to overhaul. I mentioned to Gary that I was going to have it soda blasted, he said I should plug the breather and have the blaster stay away from the input shaft and the selector shaft areas.

I plugged the breather by melting ski wax with a propane torch and dripping it down inside. A few drips that are left to harden will plug the hole in the hex head, then once it's plugged you can fill the tube. Once the wax hardens it will stop any media from getting inside (unless the blaster puts the nozzle over the hole and holds it there, but I cautioned him against this). Now that the job is done I can heat the breather with a blowtorch and all the wax will run out with no damage.

So enough text, how about the photos?

http://forums.pelicanparts.com/uploa...1242495654.jpg

http://forums.pelicanparts.com/uploa...1242495675.jpg

http://forums.pelicanparts.com/uploa...1242496133.jpg

These are before and after-- immediately after, I didn't even blow the soda off. The finish is very, very nice, the media is not as aggressive as glass bead, so there are still some oxidation stains on the aluminum, but generally it's very, very good. No damage to the seals, flanges and you can clearly see the headmarks in the original nuts.

Cost was around $60 including the two fan housings. For those of you in the New York area here is the address:

Tri-State Soda Blasting
Lem-Car Industrial Park (Right next to the Wire Shop)
100 Buckshollow Road (not a mailing address)
Mahopac, NY 10541
Phone: (914) 552-2618

Owner is John, a very nice guy, does a lot of Porsche stuff. By appointment only.

For those of you concerned about contaminating the gearbox with soda, I assure you that the soda dissolves in water. Try this at home to verify, particularly after a big sporting event. :) In any case the hardness of the media is nothing compared to sand, glass bead, aluminum oxide or walnut shells.

Enjoy!

I have a soda blaster at home and they work great. They won't get everything off, but will make anything look much better. $60 is a very fair price, given the retail cost of media - if I'd been able to find those services at that price locally, I'd have gone that route over buying equipment.

I converted my Harbor Freight pressure blaster with the the soda upgrade kit for $150. I use it in conjunction with my Eastwood blast cabinet. The setup allows me to switch back and forth between soda and glass bead. I have even found that I can recycle the soda media this way.

The soda works well on delicate surfaces where you want to preserve the original finish or even the plating. I've also used it whenever I don't want to risk media contamination like crankcases.