small part in cast iron

Discussion in 'Lost PLA casting' started by dtsh, Feb 5, 2019.

  1. oldironfarmer

    oldironfarmer Silver Banner Member

    Oooh! I like root canals too!:eek::eek::eek:
  2. Melterskelter

    Melterskelter Silver


    I avoid that line BS by using “Click and Ship.” But that only works in the States. Nice to just walk in and put the labeled package on the counter and walk out. Flat rate boxes are a bargain if the item will fit.

    That said our post office stations and substations are pleasant and professional. Must depend on who is doing the regional supervision.

  3. DavidF

    DavidF Administrator Staff Member Banner Member

    They're in the mail, you guys should have them friday...
    dtsh likes this.
  4. dtsh

    dtsh Copper Banner Member

    Now that I have one in my hand I can say the pictures don't do it justice; I dream of being able to make such good parts myself.
    It's a left and a right part so I've cut them into their respective pieces and broke the edges with a file, so nice. Next is to drop the finished pieces in the mail and wait for the pictures she promised of it reassembled.
    DavidF likes this.
  5. PatJ

    PatJ Silver Banner Member

    In the immortal words of John Denver........"like wow man.......farrrrrr out".

    Yes I agree, the photos don't do the parts justice.
    Mind blowing quality.
    Like something out of the very best commercial foundry.

    I am still scratching my head about how David pulled this one off.
    I still have testing to do, but initial thoughts are.......WOW !
    It just does not get any better than this in my opinion.

    So I am thinking that since Solidworks will make a reverse of a pattern, then why not make a printed core box, and make wax pieces, instead of melting out the PLA ?
    This way you could print just one core box and make as many wax pieces as desired.

    I am going to polish one of the pieces with the ceramic sponge disk mounted in the tool and die grinder. That should really look fabulous.

  6. DavidF

    DavidF Administrator Staff Member Banner Member

    No because the injection temperature of the wax is above the glass transition temp of the pla plastic. You can sort of get it to work with abs but the release is poor. Better off taking and making a silicone mold from the printed part...
  7. DavidF

    DavidF Administrator Staff Member Banner Member

    Then you will see the dragon skin caused by me not putting the sand onto the first layer :( Oh well I know the cause and cure...
  8. DavidF

    DavidF Administrator Staff Member Banner Member

    And for the next lost pla ceramic shell cast iron pour???
    Might actually make a mold and do it in wax, undecided....
  9. PatJ

    PatJ Silver Banner Member

    What is that?
    A print in progress?

  10. DavidF

    DavidF Administrator Staff Member Banner Member

    did you complete the distructive testing yet??
  11. PatJ

    PatJ Silver Banner Member

    Nope, have not gotten out to the shop yet today, but I did file on one of them yesterday, and it seems very machinable, and filed easily, which is not something I have achieved yet with such thin pieces.

    I also polished one of them, which was the one which did not fill the grains quite as much as the other, and the polishing brings out the grains from the plastic part.
    If the sanding sponge is used enough, you can buff out the grain, but a little more work than I would want.

    The other piece looks like it got filled a little more with the clear that you put on it, and the grain is not apparent on the front.
    The dragon skin is apparent, but it is so fine that it is not noticeable from beyond 24" away, and I would use a part like this as-is, since the surface finish exceeds anything I have ever been able to achieve, and is downright smooth by any measure.
    Basically these parts have extremely good dimensional tolerance, even with all the subtle features like the tapered holes and such, and so the parts are like a die-casting, but in iron.

    I will drill one tonight, but if it files easily, I know it will also drill easily.
    And I will break one too, but again, if it files and drills easily, then it will also break cleanly.

    This is a great process.
    I am highly impressed.
    I have seen tree structures used with wax for other metals, but I sort of assumed that the process would not work with iron.

    If I were to adopt the process, I think I would use the type of plastic that could be smoothed with acetone, and then use the silicone mold that you mention to make a core box that could be used with wax.
    That way I could make one pattern and use it for an infinite number of wax pieces/cast parts.
    Alternatively, I could fill a printed part, then cast it in aluminum, buff it a bit with the ceramic sponge, and then make a core box from silicone.

  12. DavidF

    DavidF Administrator Staff Member Banner Member

    That would be abs... unfortunately there is a few down sides to that also "warpage" being one of them on large parts (but these new print surfaces are a big help there). abs sands really nice compared to pla so I like it :) plus you can make abs glue and filler just by dissolving some in acetone..
    Im waiting on getting my hands on some of the polycast filament. I think it might be snake oil but you just never know until you try it....Stuff is like hens teeth though. Hope to get some in the next couple weeks to test out.
  13. Mach

    Mach Copper

    I was able to get 3 kg rolls from Polymaker US for $130. I'll PM you the email. Send the STLs if you want me to print the part instead.

    Check out this video. @2:40 they're casting stainless with ceramic shell?

    Last edited: Mar 23, 2019
  14. DavidF

    DavidF Administrator Staff Member Banner Member

    ohhh, 130 for 3 rolls, now thats not too bad... Ive seen that video, and call some of it "snake oil salesman" But I still want to try it and see for myself....

Share This Page