What's the best blast media for sandblasting rust off a prop flange?

[kicktireslightfires]

Does anyone have experience with sandblasting rust off of a steel prop flange?

What's the best blast media to use? Glass beads or aluminum oxide?

And which grit? I'm seeing aluminum oxide in 30, 80 or 120 grit. And glass beads in 60-80 or 100-170.

Also, what PSI do you recommend using on the gun?

Thanks!

 

[pfarber]

Is sandblasting an authorized method? Typically rust is removed chemically or mechanically (scotch brite etc).

Are you planning to retreat the flange post removal??

 

[Dan Thomas]

The engine manufacturers forbid the use of hard abrasives. Aluminum oxide is one of the harshest imaginable, being extremely hard and angular. It damages the surfaces by leaving sharp-bottomed, crack-prone pits. Ground copper slag is almost as bad. Glass bead is the mildest of the hard abrasives but even that is discouraged. Lycoming has this to say in their overhaul manual:



Blasting of the flange will damage or remove the cadmium plating. It's likely already gone if it's rusty. Lycoming says this:



Besides that, if there are corrosion pits in that flange, especially in the root radii, it's probably not safe.

http://www.aeroelectric.com/Referen...rect-Drive-Engine_Overhaul-Manual_jan2007.pdf

I wish I knew why people didn't go looking for the manufacturer's advice in the first place. There is no lack of it.

 

[Roller]

Saw a thing on using dry ice, thought that seemed interesting

 

[Magman]

Older cranks often had the plating inside hollow cranks.

When doing the SB 505 required AD I have found these in much better

condition than newer unplated ones.