Cleaning Up Aluminium Castings

[R500POP]

Rebuilding the Honda gearbox & now it's all stripped the two cast halves of the gearbox need a dam good clean. They have bee scrubbedm but are still rough & blackened due to some corrosion (not deep though).

What's the best way to get the castings cleaned up? was thinking perhaps of plastic bead blasting or similar?

[Steve_D]

Dishwasher.
Just don't get found out.

Steve

[R500POP]

Steve_D said:

Dishwasher.
Just don't get found out.

Steve

Until now not something that had crossed my kind. Still, it's late, she's toddled off to hed early, so what could possibly do wrong? I assume fairy dishwasher tablets are ok.....

[randlemarcus]

R500POP said:

Until now not something that had crossed my kind. Still, it's late, she's toddled off to hed early, so what could possibly do wrong? I assume fairy dishwasher tablets are ok.....

Might discolour the metal, and it's a PITA to get it back to the right colour. Still, will be clean.

[R500POP]

Clean is mire important than shiny (if tat makes sense)

[phumy]

R500POP said:

Clean is mire important than shiny (if tat makes sense)

Can you post the picture of your black eye after the "door you walked into"?

[peterperkins]

I intend to refurb my IMA motor casings as well, I might peen then with my shot blaster glass bead mix.

Caustic soda imersion gets to the heart of the matter! I had the aluminium front struts done a while back but they need lacquering or something afterwards.

I'll be doing my gearbox casing as well later.

[R500POP]

Caustic soda. That's sorting it nicely.

Good shout Peter.

[R500POP]

All nice and clean, it does leave a not unnatractive satin grey finish on the aluminium instead if the bright finish of new aluminum, nut they look,great.

[tinker-27]

Oven cleaner works as well or traffic film ,

[Mr2Mike]

I wouldn't use caustic soda on anything with bearing or gasket surfaces - it can eat into aluminium surprisingly quickly.

[S1_RS]

Mr2Mike said:

I wouldn't use caustic soda on anything with bearing or gasket surfaces - it can eat into aluminium surprisingly quickly.

I've used quite strong caustic soda solutions on aluminium to strip off anodising, it's never once attacked the aluminium underneath.

[R500POP]

Well, one casting is finished, measure bearing location note before and after, no measurable effect at all, but it has eaten away the corrosion.

[Mr2Mike]

S1_RS said:

I've used quite strong caustic soda solutions on aluminium to strip off anodising, it's never once attacked the aluminium underneath.

http://en.wikipedia.org/wiki/Sodium_hydroxide

Have a look at the section titled "With amphoteric metals and oxides" and "Dissolving amphoteric metals and compounds"

[R500POP]

Mr2Mike said:

http://en.wikipedia.org/wiki/Sodium_hydroxide

Have a look at the section titled "With amphoteric metals and oxides" and "Dissolving amphoteric metals and compounds"

This was a pretty weak mixture I used, about 10tbsp in around 15gals. I agree it will eat the aluminium, it's had no measurable effent in the parts.