Urethane foam?

Discussion in 'Lost foam casting' started by garyhlucas, Jun 5, 2019.

  1. garyhlucas

    garyhlucas Silver

    Can urethane foam be used instead of polystyrene? I have some 2” thick urethane with aluminum foil that peels off easily and would like to use it up.
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Wouldn't recommend it. The usual motivation is to use the foaming/expanding insulation (it's urethane) as a moldable pattern. But, I never tried to use urethane. A few years ago when I started lost foam casting I searched the subject and the threads & videos I found reported very poor results and very toxic fumes. Apparently the urethane doesn't exhibit the same liquid/gaseous phase decomposition as polystyrene and the decomposition occurs at higher temperature. This was all at similar densities toPS. Higher densities would likely be worse, just like PS.

  3. I use it for pattern making: you can carve/sand shapes to size, then sealing, painting and waxing it before taking a fibreglass female mould off it.
  4. Rasper

    Rasper Copper

    As Mark said, it's wonderful stuff for carving and sanding into the most complex shapes, but you do not want to be melting it or burning it. The fumes will kill you. or cause permanent damage to your internal organs.

  5. garyhlucas

    garyhlucas Silver

    My daughter worries about everything so when we pour we are both wearing respirators with organic cartridges.
  6. oldironfarmer

    oldironfarmer Silver Banner Member

    It's never wrong to wear a respirator.
  7. DavidF

    DavidF Administrator Staff Member Banner Member

    Doesn't work well under water ;) :eek: :D
  8. oldironfarmer

    oldironfarmer Silver Banner Member

    A Self Contained Underwater Breathing Apparatus would be considered a supplied air respirator which is used in atmospheres immediately dangerous to life and without sufficient oxygen like high H2S, HF acid vapors, high altitudes, and, ummm under water.:eek::rolleyes:
  9. garyhlucas

    garyhlucas Silver

    I’ve heard pouring hot metal under water is difficult.
  10. crazybillybob

    crazybillybob Silver Banner Member

    The Steam bubble really make it hard to see what your doing.

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