8 replies to this topic

[Pauly]

Hi guys,

Thinking about getting my ali engine stuff shotblasted/sandblasted (gearbox case/transfer case), will the casting need to be bare? as the bearings for the transfer gears are still in the transfer case and I dont want to remove them if I can help it, same goes with the gearbox case, even though it a bare case the only thing left in is the bearing for the idler will it need removing?

Thanks.

Paul.

[dklawson]

Take the bearings out first. It will end in heartache if you don't.

I would suggest shot-peening OR glass-bead blasting. Sandblasting will produce a different finish that will corrode quickly and won't stay shiny. Once it's been blasted, wash-wash-wash the gearbox and clutch cover. You must get all the media out.

[Cooper-202S]

If your just trying to get them clean not remove paint an the like, then de grease them thoroughly and
a hot trip through an old dishwasher with a couple of tablets does the trick.

[MRA]

We use different media to that suggested above and the finish is like new... except for any damage caused by previous incidents etc...

Glass bead is ok... do not use alluminium oxide as it corrodes the case and leaves little white spots all over it

I would suggest that you leave the bearings in place and treat them as scrap....... this way the case critical dimensions will not be affected

We have done hundreds this way and charge £25 for a case with diff housing, two diff side covers and the speedo housing

[dklawson]

I hadn't thought about leaving the old bearing races in and using them as masking. That's a good idea.

[ANON]

just get it soda blasted, it won't damage any of the surfaces.

[liirge]

please be carefull, you will ruin all the important surfaces around the bearings if your not careful...

[MRA]

Soda glass bead does damage surfaces that are made of alluminium and are held to 0.0002" yes that is 2 tenths of a thousandths of an inch, what can happen is the surface is deteriorated and thus allows the bearings to spin.
The amount of alluminium dust that is in the soda glass dust will give you all the proof you need

[ANON]

was talking about sodium bicarb. should of said, sorry.