Soda Blast vs Other Media

Rob58

Pre-takeoff checklist
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Any comments out there on the use of soda blast media for cleaning various metal parts (steel, alum, SS)? It seems like the soda blast media is just a gentler way to clean up parts as opposed to glass bead or other media. But somewhere I thought I read about a downside to using soda media. Maybe it leaves some type of residue? Anyway, feedback from our resident gurus is much appreciated!
 
The big local seaplane shop uses soda blasting to refinish floats. I'd think it would require a good rinse to clean any residue but any blasting media requires that and a water soluble media is probably easier to rinse than most.
 
this ain't for the novelist....one can ruin a set of skins in a minute if not done correctly.
 
Soda blast is awesome. But in some materials it changes the pH of the metal causing issues for coating adhesion like paint. The surface needs to be cleaned after soda blasting to remove ALL residue. A think film of soda is left behind that must be removed.
 
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Soda blast is awesome. But in some materials it changes the pH of the metal causing issues for coating adhesion like paint. The surface needs to be treated after soda blasting.
Bingo! This is the information I was looking for and reminds me of what I read somewhere before. Since the soda media is alkaline I am guessing that it is best rinsed with some type of acidic liquid to neutralize? Any specific recommendation? Thanks very much!
 
But in some materials it changes the pH of the metal
Got a valid reference for that?

Any media used must be cleaned = Etched and Aluminum must be alodined after cleaning.
NEVER use Vinegar on aluminum.
 
No one should use full vinegar. A solution of water with vinegar works for cleaning most metals. Plain water under some pressure works as well. This is for mildly cleaning a molecular residue of baking soda.

That's not the end of the required prep needed before primers and finish coats are applied.
 
Got a valid reference for that?

Any media used must be cleaned = Etched and Aluminum must be alodined after cleaning.
NEVER use Vinegar on aluminum.
so...in English....what is an etch?
 
so...in English....what is an etch?
It is an approved chemical bath used to clean and improve adhesion or to provide protection .

use the wrong one defeat the whole purpose
 
Soda gets into every nook and cranny. There was a dry ice blasting method that never took off, seemed like a good idea.
 
Soda gets into every nook and cranny. There was a dry ice blasting method that never took off, seemed like a good idea.
I found a place locally that does it. I got an estimate to strip the paint off my plane... would have been over $8K just for the stripping. That was based just on the square footage, with me doing all of the disassembly work.
 
I found a place locally that does it. I got an estimate to strip the paint off my plane... would have been over $8K just for the stripping. That was based just on the square footage, with me doing all of the disassembly work.
Youch
 
Surprising to me, AC43.13-1b does not say anything about type of blasting media.
 
Surprising to me, AC43.13-1b does not say anything about type of blasting media.
see Advisory Circular AC 43.13-1B Chapter 6 section 8

(2) Blasting.

(a) Abrasive blasting may be used on aluminum alloys using glass beads (Spec. MIL-G-9954) sizes 10 to 13, or grain abrasive (Spec. MIL-G-5634) types I and III may be used as an alternate method of removing corrosion from clad and non-clad aluminum alloys. Abrasive blasting should not be used to remove heavy corrosion products. Direct pressure machines should have the nozzle pressure set at 30 to 40 psi for clad aluminum alloys and 40 to 45 psi for non-clad aluminum alloys. Engineering approval should be obtained prior to abrasive blasting metal thinner than 0.0625 inch.

(b) When using abrasive blasting on aluminum alloys, do not allow the blast stream to dwell on the same spot longer than 15 seconds. Longer dwell times will cause excessive metal removal. Intergranular exfoliation corrosion is not to be removed by abrasive blasting; however, blasting may be used with powered corrosion removal to determine whether all exfoliation corrosion has been removed.
 
Crazy, I opened the FAA’s version of that chapter, searched blasting; several hits but nothing about glass beads -thanks.
 
It's kinda funny how everyone is obsessed with acid etch and alodine on aluminum. What does hartzell and McCauley use on aluminum props? Sherwin Williams industrial wash primer and instrustrial polyurethane enamel (Polane T).
 
Alclad sheet would have the coating stripped off during blasting, wouldn’t it?

I use Variprime. I'd do soda blasting if I ever did another set of floats. Stripping is not fun.
 
I use walnut shells for just about everything. In the past I used glass beads, but they produce silica dust, and if you clean engine parts, cleaning can be heinous, as just a few specks of beads can harm an engine. Sand blasting is left for heavily rusted steel parts. Carbon dioxide blasting is also a "thing", with the benefit of leaving only the paint/corrosion/etc. as waste. There is also a "wet glass" method, that uses ground glass and water to strip paint. It's used on cars (there is a franchise that does it, around 1K per car.) I don't know if I'd try it on the skin of a Skyhawk, however. As with everything, cost may determine which is best.
 
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