Chemical cleaner

[Stuart Giles]

a bump for carb cleaning for those without ultrasonics! I'm more worried about internals so may try the meths. But does acid actually hurt mazac and brass, or just the oxidised surfaces we want to remove?

Oxalic acid (AKA wood bleach) is relatively benign, I've never used it on ali/mazac but with steel, cast iron etc, where it only removes the oxide, doesn't attack the metal at all. I have used this on seriously rusted precision machine tool parts without any issues. Here's a before and after on a sump I soaked in Oxalic acid solution a few years ago.



Of course, there's very little danger of an A7 sump ever suffering any rust