Lost PLA bronze casting of John Lennon statue

Discussion in 'Lost PLA casting' started by Rotarysmp, May 10, 2020.

  1. Rotarysmp

    Rotarysmp Copper

    Hi all,

    My wife is a Beatles fan, so I did a John Lennon statue for her, using the models I bought from turbosquid.

    I need to get a little more serious about lost PLA, as there were simply too many errors.


    I've been watching Jeff the Veg Oil Guy videos. His are excellent, great to learn from. Time to get some more investment and try again.

    Mark
     
  2. DavidF

    DavidF Administrator Staff Member Banner Member

    Yes, Have to give the vegi oil guy some credit, he does an excellent job with his videos. Something tells me that is is actually the vegi oil Guys and not guy though...
     
  3. Peedee

    Peedee Silver

    I did the lighting in the cavern quarter for a permanant 'Lucy in the sky with diamonds theme' Thousands of lights and a shed load of 316 stainless framing to hold it all up, was a lot of fun and I almost became a beatles fan in the process.

    Nice cast
     
  4. Rotarysmp

    Rotarysmp Copper

    Thanks. It was a fun attempt, and I look forward to trying again with a little better preparation.
     
  5. Rotarysmp

    Rotarysmp Copper

    After thinking about it for a couple of days these are the process improvments I want to make for the next attempt:
    - Transparent PLA
    - One piece print (if possible) otherwise torso as before, legs printed upside down torso to bed) and the bases separate. Weld together with fine soldering iron.
    - Clear coat to ensure no pinholes in layers, and for better surface finish, and reduced striation.
    - Buy a 22.5kg bag of investment. Are there any which have a bit longer working time than 8 minutes? Any recommendations? I was currently looking at cousins goldstar xl, but it is only 8 min.
    https://www.cousinsuk.com/product/investment-powder
    - Make up a vaccuum chamber to degas the invenstment. By the way, painting the model with the dishwasher glass corrosion glycol stuff resulted in way fewer air bubble warts than the first statue (Paul).
    - Source some decent bronze. I hate brass in the mix, as the smoke from flaring off will likely get me in deep guano in my inner city abode. I have a lead on 20+ kg of clean bronze swarf from a CNC machining job a aquaintance did. Does Bronze have the same bifold/oxide skin problem as Aluminium alloys? It is only a statue, so I am not concerned with structural integrity.
    - Flux (what is used for bronze) and skim better.

    Any other suggestions welcomed.
    Mark
     
    Last edited: May 11, 2020
  6. Peedee

    Peedee Silver

    I can only suggest the following, there are others here more qualified than me!

    Swarf, will create lots of oxides, not sure I ever got into the bifold theory but definately use charcoal as a cover and try to press the charge material into pucks to reduce exposure. I'm pretty sure most here would suggest virgin ingot to save you the headache.

    Flux, borax used sparingly for copper alloys if at all. It eats crucibles because it's... well a flux! Foseco make a coverall but not sure if that is easily available and the last of mine is sadly gone.

    The other guys will chip in with more constructive comments I'm sure.
     
  7. Rotarysmp

    Rotarysmp Copper

    Is a broken glass cover worth doing?
     
  8. Peedee

    Peedee Silver

    I tried glass and ended up with a gooey mess that was hard to skim but some peeps have had good success with it so I probably did something wrong.
     
  9. Petee716

    Petee716 Silver Banner Member

    I've just now watched your video. Nicely done as usual. I was surprised to see how much investment you had to pour the second time. Even with the vibration I guess it was pretty thick the first time. I can't comment on your model making or investment practice as I have no experience at all but your observations and thoughts moving forward seem sound.
    I've been pouring everdur most recently from known-source scrap and have had very good performance in the crucible in terms of smoke and dross. That is to say almost none. No cover needed. Any real problems that I've had with it in my sand castings have been from gating, overheating, etc, so it was problems with me not the metal. I have the components to make my own but have yet to make the effort to make it. Zapins and Jason haven't had good luck making it but Rasper and others seem to do fine with it. I'll give it a go one of these days. From what I hear and see from others melting raw copper can be an uphill battle to begin with and some of the unwanted components in your scrap probably wasn't helpful. In the lists of priorities from those who really know, a clean melt is usually number one or two, so there's that.
    I commend your bravery with the mixer but be careful. You're skating on thin ice! Lol.


    Pete
     
  10. Jason

    Jason Gold Banner Member

    Never done a cover or ever used flux. Not even once! I'm too lazy to make bronze at this stage. I still haven't tried it, but will someday.
     
  11. Rotarysmp

    Rotarysmp Copper

    Thanks Pete. I have bought the transparent PLA Filament, and have a lead on clean bronze, so next I need to start printing and order the investment powder.
     

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