I have a broken off brass needle stuck in a caste aluminum hole. (It’s the pilot mixture jet on a carburetor).

I was wondering if there was a chemical that would dissolve the brass while not reacting to the aluminium.

Previously I’ve tried:

  • Using thermal expansion and contraction to loosen it.
  • Attempting to poke it out.
  • Using an air compressor to blow it out.
  • 1
    $\begingroup$ Concentrated nitric acid will dissolve common brasses, but not aluminum. But, even if it works well, it would be slow going for a needle in a small hole. Good luck! $\endgroup$
    – Ed V
    Jun 19, 2021 at 0:39

1 Answer 1


Not likely. Ammonium hydroxide will attack brass, but at high concentrations and not very fast. And worse, I don't easily find data for aluminium in concentrated $\ce{NH4OH}$, probably because it has poor resistance.

I think you are stuck with mechanical options. Simplest is another carb or subsection. Drilling it out is obvious. Strangely enough, I have bits down to possible 0.010 " diameter but I don't know where you would buy tiny drill bits; likely you will need a few. They use collets rather than chucks to hold them , so you also need a collet or two. Sounds like more expense than a carburetor.


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