4 replies to this topic

[nev100]

Hi All.

I've just had my gearbox casing vapour blasted.
Thinking getting it back to new before rebuild was the way to go.

Now heard contrasting thoughts.
One being the media used will be inbedded in the aluminium...and will come out in the oil once running and then ruin the crank..

Also,where the bearings go has been cleaned. Will the tolerances be affected??

Should I be concerned about this...??

I'd understand if it was the Space Shuttle...but let's be honest, it's an A series.

Many thanks.

[InnoCooperExport]

never heard of the media embedding and then coming out when the oil is added, but if this is a worry you just need to clean it all up before putting it in use. You could even "wash" it with oil. 

 

When you say the mains caps have been cleaned do you mean blasted? That's not something I would normally do, I would check them for any scoring or pitting and they might need to be checked for roundness. Last thing you want is the bearings to spin. As a rule don't blast anything that's a machined or ground finish (i.e. bearing carriers, certain mating surfaces)

[cal844]

You shouldn't really media blast the bearing surfaces of an engine or gearbox. Vapour blasting (just high speed water) should clean the bearing surfaces up well enough. I'd then blow the item dry with compressed air. If you want to be scrupulous with the cleaning you can use brake and parts cleaner once dried

[nev100]

Many thanks for the replies.

I think I'll take the gamble and use the case after a good clean.

Knew I could rely on TMF to get good advice.

[Spider]

Sand (abrasive) Blasting and the likemcan get stuck in the Aluminum, but only of it's done by someone who's utterly careless. And really, this type of aggressive cleaning isn't appropriate for an Ally Casting in any case.

 

I've had loads of them Soda Blasted and they are fine. They do need a wash after with a pressure washer or in the parts washer. This I find is a great process for removing paint and oil stains (to a point). You could blast away at the same point on the casting for a week with this and it will not erode or remove material from the Casting. It's done dry (or should be)

 

Vapor Blasting is similar but is done wet and it uses a fine, rounded glass bead. It was developed (in part) for alloy parts and is ideal. It too won't remove material from the Alloy.

 

If in any doubt, have a chat to the firm before leaving your parts with them.