About cleaning tuning slides?

Discussion in 'Trumpet Discussion' started by SVTrumpet, Feb 26, 2010.

  1. SVTrumpet

    SVTrumpet New Friend

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    Is it safe to use Brasso on tuning slides? Some of my slides have aquired a nasty red rot and I want to get rid of it[​IMG]
     
  2. oldlou

    oldlou Forte User

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    Is it truly red rot, or, is it simply a bit of oxidation. Oxidation turns the brass brown, while red rot is more pink than red, and is quite striking in appearance. If it is just oxidation it will hurt nothing and can be safely removed with a mild brass polish. Caution, over cleaning will result in removing enough material that the airtight seal will be destroyed. If the slides move well and don't leak air or water, just don't look at them.


    OLDLOU>>
     
  3. SVTrumpet

    SVTrumpet New Friend

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    It is red rot. My main problem is that the tuning slide grease that I use on the main slide dries up way to fast.
     
  4. ComeBackKid

    ComeBackKid Fortissimo User

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    I would suggest that you search this forum for threads on red rot but unfortunately the search function sort of sucks and it appears that it will not search on 3 (or fewer)-letter words, which included both 'RED' and 'ROT' (it won't even search on both with a space). It will search on 'REDROT' but few of the threads contain that word so results are skimpy.

    So, I will recap a lengthy thread from about 6 months ago related to this. There are two definitions for 'red rot' - one used by metallurgists and one used by brass instrument technicians and players.

    The one used by metallurgists relates to any form of oxidation which turns the brass a reddish/pinkish color - even when it is only superficial and on the outer surface. The one used by trumpet players refers to the specific condition where de-zincification starts on the inside of the instrument and then progresses through the metal finally appearing on the outer surface as a circular pink area with a black dot in the center. On trumpets, this most commonly is seen on the surface of the leadpipe and the crook of the main tuning slide.

    If yours is a dry, crusty surface on the inner tuning slide pipes which cause a 'scraping' sound when moving the slide, it may be simple corrosion/oxidation (whether pinkish or brownish color). This type of oxidation is easily removed with Brasso or Tarn-X or any type of metal polish. As Oldlou cautioned, it is possible to over-polish the inner pipes thus reducing the diameter and increasing the clearance so that water leaks occur. However, a light treatment with polish should not cause a problem unless the slide is already on the loose side. I have polished inner slide pipes on slides that were tight just to make them looser and it takes quite a bit of polishing to make a noticeable difference. But, even if that were to occur, there is a recent thread regarding a DIY recipe for slide grease made from beeswax which is viscous enough to seal the slide and prevent leaks.

    If you have Brasso handy, it is an excellent means of removing the oxidation. In fact, Brasso has an ingredient (ammonia, I think) which I have not found in any other product and it is the best thing I have found for removing the pinkish tarnish. Just clean the slide pipe first to remove any grease and then apply the Brasso, rub it around a bit and then burnish the brass with a tight-weave cloth.

    So, go for it - just be careful.
     
    Last edited: Feb 27, 2010
  5. Brekelefuw

    Brekelefuw Fortissimo User

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    I have never heard red rot be called oxidation. They are two separate things. Oxidation creates a protective layer on the raw brass, while red rot is the zinc leeching out of the alloy.

    WARNING: Using ammonia based cleaners on brass can cause something called Season Cracking. THis means the brass becomes very brittle and cracks very easily. DO NOT USE AMMONIA ON BRASS.
    I have seen an entire tuba become cracked all over from this. Brass - Wikipedia, the free encyclopedia
    Season cracking - Wikipedia, the free encyclopedia
     
  6. SVTrumpet

    SVTrumpet New Friend

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    Ok, well I already used the Brasso on the main tuning slide and it took all of the oxidation and red rot off. What do you guys use for tuning slide grease?
     
  7. Brekelefuw

    Brekelefuw Fortissimo User

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    Red Rot typically appears as little red dots that start on the inside of the tubing and works its way to the outside.

    You can't really cure a trumpet of red rot without replacing the part.
     
  8. ComeBackKid

    ComeBackKid Fortissimo User

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    OK, based on this quote from an article about red rot, that makes sense. I meant to imply corrosion, not oxidation, so you are correct. The article quote below contains a section (I did not copy the entire thing) that mentions that the reddish color (hence the name) is created by reaction with acidic materials, not oxygen. But, what I was trying to say is that both the surface corrosion and the more serious internal de-zincification are technically referred to as red rot although that is not how it is commonly used on this forum. The article does use the term "True Red Rot" for the more serious type.
    What is "Red Rot"? (an article from EmpireBrass.com)


    "Red Rot" is commonly used to refer to any reddish patch of corrosion on a copper-based alloy, such as brass. However, this loose usage covers two distinct but related conditions, surface corrosion and deterioration of the alloy due to de-zincification.
    Red rot is found in brasses, which are alloys of copper and other non-ferrous metals, such as zinc. As the alloyed metal, most often zinc, is corroded out of the brass, a lattice-work of copper is left which is reddish in appearance.
    If this happens on the surface of the part it is relatively harmless. Only a very thin layer of zinc has corroded away, and the part will likely continue to perform well.
    However, sometimes the de-zincification is extensive. True Red Rot is the complete breakdown of the alloy, and it occurs from the inside of a tube and proceeds outward. In this case, the loss of zinc from the brass is substantial and throughout the thickness of the part. It is identifiable as a reddish patch on outside of the tube, roughly circular, with a pin-point dark spot in the very center. At this spot the alloy has failed completely, leaving a weak structure of copper behind. You can put a probe on the spot and push all the way through without effort. The metal has failed.


    This is an interesting point. The Wikipedia article on Brasso mentions it was developed in 1905 and does, in fact, contain ammonia. So, it raises a valid concern. Even though Brasso has been used for over 100 years, it may be that the types of things that it is used on - ornamental items, hardware, etc - are not susceptible to cracking due to their mass. The example in the article - bullet casings - and brass instrument material - the tuba you mentioned - are relatively thin and, thus can be more easily affected.

    In the case of the tuba that cracked, had it been polished extensively with Brasso or was it exposed to ammonia in some other way? If it was Brasso, that is certainly information that the trumpet community needs to know.
    Thanks for the insight.
     
  9. Brekelefuw

    Brekelefuw Fortissimo User

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    We don't know what the school used on the horn. It could have been Windex with Ammonia, or something else completely. It wasn't brasso. The horn had a nice patina on it.
     
  10. dhbailey

    dhbailey Piano User

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    I use vaseline (or store-brand petroleum jelly) -- I've used it all my instrument-playing life and I use it in my repair shop. I've never had any of my slides get permanently frozen using this, even on personal instruments I haven't used for many years. The slides always move, even if occasionally they need a little persuasion.

    Commercial slide grease, on the other hand, has dried in many of the instruments I work on in my repair shop, and in those cases I need to disassemble the slide and work out each of the stuck tubes independently and then reassemble the slide. And sometimes I need to replace the inner/outer tube combination because they have become so stuck that then can't be separated.

    I've never run into that with instruments which have had their slides lubricated with vaseline, however.

    The use of true synthetic slide creams is relatively new so that I don't have an impression whether an instrument lubricated with them and then not used for 40 years will be easily disassembled or will need major repair work.

    The best thing, though is the advice I tell all my clients when they pick up an instrument which was in for repair due to stuck slides -- move all the slides every day, in/out and returning to where they need to be for proper intonation. If they're moved every day, they'll continue to move every day. It's only when they are left unmoved for a lengthy time that they become stuck.
     

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