Bell 10 LB military

Discussion in 'Metal casting projects' started by HT1, Aug 29, 2023.

  1. HT1

    HT1 Silver Banner Member

    I recently got access to a lathe so I could finish my bell cast many many years ago
    with it done I got to test something , how alloy affects tone

    First off I have a Loeffler bell Made IAW MIL-B-674C, which is the older imperial version of the current metric DOD Spec below

    Loeffler Still Makes these bells I got a current quote for the 10Lb bell $1850 +shipping 30 week lead time
    the DOD specs call for casting out of C87200, which is an inactive Silicon Bronze alloy so they are probably making them out of C87300, Evendur

    an older , but helpful reference for bell is on page 171- 173 of the Naval Artificer's Manuel

    it calls for Making bells from 78/22 Tin Bronze ( go read the reference I love that it specifies Lake superior copper) hardware for the bells calls for Gun Metal or Tobin, Tobin is now C85700( took some serious digging to hunt this jewel down) Gun metal would be C90300, I have cast entire bells in this alloy in the past, and they sound really good.

    I cast My bell out of scrap Brass, that's right what I use for Plaques generally shooting for 60/40 Muntz metal but no test of spec

    the first bell is mine , the second is the Loeffler, which was my pattern so the first bell is Shrinkage or about 3% smaller

    I tried to get everything as equal as possible , you can hear the difference clearly

    I did build a stand for it looks great sounds good with nothing to compare it to


    V/r HT1
  2. The bronze bell definitely has more resonance than the brass, both look awesome. Regarding the Lake Superior copper specification, I remember reading about how some copper mines had traces of tellurium which made the copper free machining. Some mines had traces of selenium which was suitable for early electronics like selenium rectifiers maybe.
  3. HT1

    HT1 Silver Banner Member

    I did some insane deep diving on these subjects, here is a good one on the "names" and compositions of many metal alloys for military use

    Lake Superior copper was 99% pure, and since this is from before Electrolysis for refining copper would have been widespread, that line would have gotten you high quality pure copper

    Lindsey used to publish a book that was nothing but old names brought up to date like sal ammoniac = Ammonium chloride (one I know, its a flux for Babbit we used relining bearings)

    V/r HT1
  4. There was a copper refinery south of here and a former worker was telling me how the tank sludge was carefully gathered up into heavy gauge 200 litre drums and shipped off: there's all sorts of metals like platinum group metals, gold and tellurium in such sludge.

    So even in 1929, the US Government had to start defining some of the names of alloys, you can almost hear the frustration that the Bureau of Standards writer would have with old and loose definitions.

    Sal ammoniac is hard to find, I eventually sourced some at a stained glass supply shop. I was able to make the stuff by mixing cloudy ammonia with hydrochloric acid: had it in a bucket slowly evaporating and crystallizing.
  5. HT1

    HT1 Silver Banner Member

    I suspect Sal Ammoniac is rather common, but no one uses the name , ammonium Chloride flux got me lots of results, though alot of it was zinc ammonium chloride, which is the flux I use for tinning the mugs ,

    i remember tinning 14 inch main shaft bearings with Sal Ammoniac , you got a guy on one side of the bearing with a diesel burner heating it while you wire brush the flux and molten tin onto the face all while trying not to breath, its amazing I'm not in a cancer ward

    V/r Ht1
    Tobho Mott likes this.
  6. That flux with hydrochloric, ammonium chloride and zinc chloride is pretty hard to beat, you can even use it on stainless steel for tin-lead soft soldering. There was a local brand of zinc chloride and hydrochloric acid that wasn't as good and it even has the ammonium chloride added to it in the newer versions. I haven't tried it yet but have seen people using alloy wheel cleaner (10% hydrofluoric acid) to good effect on hard to solder electrical connector pins: a lot of that stuff like inline fuses sold in retail stores has passivation on the plated terminals to keep it looking shiny on the store shelf but it makes it a real pain to get solder to initially stick.

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