Announcement

Collapse
No announcement yet.

Disolving brass

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Disolving brass

    I need to remove a broken brass screw from a carbon electrode. can a I use my derusting setup for this?
    Jim

  • #2
    > can a I use my derusting setup for this?<
    Not knowing what that is I couldn't say.
    I think [note! think] that carbon, as in graphite, will not be atacked by
    an acid, I would try , on a bit of the carbon, a drop of Nitric acid and if
    no reaction would then proceed to disolve the brass with that.
    ...lew...

    Comment


    • #3
      Thanks Lew; I tried the electrolisis, don't think it's going to work, it'l make a big green glob on the exposed brass but doesn't seem to reduce it's size.
      I don't have a source for nitric acid, plus I've heard it's pretty nasty stuff, so I'll probably just have to replace it. The body of the screw is only about 3/32 and I doubt I could drill it without destroying the electrode.
      Jim

      Comment


      • #4
        Originally posted by J Harp
        I need to remove a broken brass screw from a carbon electrode. can a I use my derusting setup for this?
        If I was going to try this I would use Sulferic Acid, as it will react with both the copper and the zinc in the Brass, to form either Copper Sulphate, or Zinc Sulphate in solution thereby removing the screw.

        Ken

        Comment


        • #5
          ferric chloride will dissolve the brass

          Comment


          • #6
            Originally posted by K Barton
            If I was going to try this I would use Sulferic Acid, as it will react with both the copper and the zinc in the Brass, to form either Copper Sulphate, or Zinc Sulphate in solution thereby removing the screw.

            Ken
            and you can get sulfuric acid in the plumbing section of Home Depot etc as a drain opener.

            Comment


            • #7
              Sulphuric acid will not dissolve the copper in the brass in the cold. Nitric acid will dissolve copper and zinc but beware of the gases that come off. The best bet would be one of the printed circuit board etchants such as ferric chloride or ammonium persulphate. It will be hard to decontaminate the carbon after using either of these.
              Mike

              Comment


              • #8
                Household Ammonia will disolve Brass.

                Comment


                • #9
                  Got er done. Baling wire fix.

                  Gave it two hours in the battery acid, no luck.
                  I used a carbide burr in the Dremel to cut away enough of the graphite that I could get hold of the screw with pliers, still wouldn't budge. Found a brass screw with nut which would fit the wire terminal, chucked it, cut the head off and faced it. Drilled it 5/64 about 3/16 deep, and filed the stub of the old screw down till it would go in the hole.

                  I fluxed the pieces and soft soldered them together. Now I have a working vaporizer again. I just don't buy the throw away philosophy, if I can think of a way to fix it I will. Thanks for the ammonia tip Al, I'll try to remember that in case I have to do another one.
                  Last edited by J Harp; 03-12-2011, 05:58 PM.
                  Jim

                  Comment


                  • #10
                    dissolving brass

                    Contrary to some well intentioned advise, Home Depot doesn't sell "Sulfuric Acid" ie. "Battery Acid", as drain cleaner. Usually drain cleaner is a combination of sodium hydroxide (bleach), and sodium hypo-chlorate (lye) which I believe are both "basic chemicals", the opposite of acids. If either are mixed with sulfuric acid (you will be producing some pure chlorine gas) and we will be potentially losing several of our beloved Home Shop Machinist BBS members due to chlorine gas poisoning. People are poisoned or die every year from mixing drain cleaners and acids. Don't take my word for it, check with the American Association of Poison Control Centers.
                    I've seen some "Questionable" advice offered on this website (and many others) about different topics concerning such things as electrical wireing, welding tank storage, and other topics that if followed, have the the potential of getting someone injured.
                    There is a wealth of good advice available on this website, and I'm sure everyones intentions are good, but if there is any doubt about safety, check with an expert. Just my two cents. Good day.

                    Comment


                    • #11
                      Err,Sulfuric (Sulphuric in the mother country) does dissolve Copper.

                      H2SO4 + Cu = CuSO4 + H2, Copper Sulphate (Sulfate) and Hydrogen or it did when I was at school. The Zinc is reduced to Zinc Sulfate (Sulphate).

                      Regards Ian
                      You might not like what I say,but that doesn't mean I'm wrong.

                      Comment


                      • #12
                        ammonia will do the job

                        rollin'

                        Comment


                        • #13
                          The trumpet shop where I work uses a chemical bath that is largely sulfuric acid (granted, we add some mystery powder...) to strip nickel from trumpet valves that will be eventually resized by re-plating. If we break off a tap or steel screw on a brass part, we dump whatever it is in the strip tank for a few days till the offending steel is gone. The brass seems none the worse for the experience.

                          Comment


                          • #14
                            Originally posted by Circlip
                            Err,Sulfuric (Sulphuric in the mother country) does dissolve Copper.

                            H2SO4 + Cu = CuSO4 + H2, Copper Sulphate (Sulfate) and Hydrogen or it did when I was at school. The Zinc is reduced to Zinc Sulfate (Sulphate).

                            Regards Ian
                            Sulphuric acid will not dissolve copper at room temperature. Copper is below hydrogen in the electrochemical series so it cannot displace hydrogen from the acid. Hot concentrated sulphuric acid will convert copper to copper sulphate according to the equation:
                            2 H2SO4 +Cu = CuSO4 + 2 H20 + SO2
                            This reaction is basically an oxidation reaction rather than a displacement reaction.
                            Mike

                            Comment


                            • #15
                              Hello HSM members, 1st time here. I've read a lot of very helpful tips on this site. Thanks for being here and sharing.

                              Quote:J Harp Gave it two hours in the battery acid, no luck.

                              If the OP used battery acid from a battery, or refill box/bag, it would have had to be boiled off till a dense smoke forms. If used straight from the battery, it will be severely diluted.

                              I'm not saying it will eat brass, just that battery acid must be distilled to get any good strength sulfuric acid.

                              Ben

                              Comment

                              Working...
                              X