Recommendations On Investment Materials

Discussion in 'Lost PLA casting' started by David McCauley, Nov 11, 2020.

  1. Hello,
    I am looking for a new investment material. I have been using plaster and sand and it usually works fine for lost wax but will usually crack with the higher temperatures required to burnout PLA. Ive been looking at the suspendaslurry but have yet to pull the trigger, its pretty pricey but it looks like my only other option... What do you all use?
  2. DavidF

    DavidF Administrator Staff Member Banner Member

    Suspendaslurry for shell casting, and Ransom and Randolph plasticast for block casting lost pla. Or Ransom and Randolph ultravest for lost wax block casting..
  3. Thank You!
    DavidF likes this.
  4. Jason

    Jason Gold

    +1 Suspendaslurry. It's actually not that expensive when you do the math on it. You can buy 1/4 the amount from shellspen for 10times the money if ya want.
    The 5gallon bucket will last almost 2years IF you keep it inside the house in the AirCon. Do not let it freeze or it's trash. Also, once a month
    run a mixing paddle on a drill through it to keep it suspended. It will settle out if you don't and you will hate yourself when you try to get it moving again.

    At this time of year, I highly doubt R&R would even ship the stuff this time of year. They usually won't. You will need 1 bag of A and 1 bag of B silicas.
  5. Hey Jason,
    I ended up ordering the suspendaslurry, I have done one casting with it so far. I also have a guy from work hooking me up with some slurry he makes for an university, so I will try that too and compare. How many layers do you normally do for your shells?
  6. Jason

    Jason Gold

    Hi David. Yeah I run 2 layers of slurry and fine silica. Then I do 5 layers of slurry and coarse silica. After that, one final dip of just slurry to seal it. That one is kinda optional in my experience. I tend to do it more when I water boil dewax. Now if you are running flash fire dewax, R&R has a tech sheet on that I recommend you read. The short and curlies are NO Direct flame impingement (which is hard I know) Next is NEVER get the shell about 1900degrees. Something changes and makes it more prone to cracks. Another big point R&R FAILS to make is, you should wait 48hrs AFTER your last dip in slurry. It is really important the shell is completely dry before dewax. I finished these 2 shells today. 7layers and a couple extra layers on just the pouring cup. (they crack on me for some reason) Then a final seal coat. I'll boil them out tomorrow as waiting for 48hrs doesnt matter if you are sending them for a swim anyways.
    I will gently dig out my hooks and open the cup so I can see into my hollow main sprue. I dont play that game with 10degree cooler feeders. Doesnt seem to matter with boil out.
  7. Awsome! thanks for the helpful info! Id love to see the castings when you finish them!
    Jason likes this.
  8. Jason

    Jason Gold

  9. dennis

    dennis Silver

  10. Jason

    Jason Gold

    Lost half an eyebrow in a dewax video.:oops::eek::(
    Tobho Mott likes this.

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