small part in cast iron

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

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

    Melterskelter Gold Banner Member

    .

    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.

    Denis
     
  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 Silver

    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

    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.

    Edit:
    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.

    Edit02:
    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....
    20190323_110256.jpg
     
  9. PatJ

    PatJ Silver

    What is that?
    A print in progress?

    .
     
  10. DavidF

    DavidF Administrator Staff Member Banner Member

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

    PatJ Silver

    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 Silver

    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....
     
  15. Hello!!

    I am new here. And i am wondering if any of you have tried casting black powder gun parts/ normal gun parts yet.

    I would be really easy to just cast PLA 3D printed parts.

    I have the prints of this website: https://www.assra.com/Archivelibrary.htm

    Its single shot rifles. And i am looking at the Winchester High Wall 1886 rifle, as a concept.

    I havent 3D drawn the files completely yet. But a few evenings will get it done im sure.

    What actually made me look into casting is this file "M16 trigger" [​IMG]https://ibb.co/PGMGbqt (Its only there for a month..)

    And this video convinced me:



    You can make guns, and gunparts with casting. The thing is. What is the right approach? What plastics are the best? What mould material is the best? Ive seen jewlers investment powder where is vacuum needed when pouring. Ive seen boxes with sand, where the pour is performed. Ive seen hard sanded shell methods.

    The sanded slurry method seems to be the easiest. You slurry and sand your parts enough times. Burn out the plastic, and you pour with hot slag skimmed steel, and thats it.... But would it have good enough "resolution"?

    And i dont know what is a good method to heat the steel to the right temperature.

    Gas, induction??
     

    Attached Files:

  16. dtsh

    dtsh Silver

    Thanks, you guys reminded me that I promised to post images of the part in place and didn't follow through. Since the part was cast, mom passed and the chair became mine. I couldn't find the original screws, no telling where they got off to, so I used what she had in the baggie with the rest of the parts. Eventually I hope to replace them with more appropriate screws, but I was worried of additional damage and loss if not reassembled.

    Here in the part is just a bit left of center.
    chair.jpg

    And just because, a few other shots of the chair for context
    chair2.jpg

    chair3.jpg

    chair4.jpg
     
  17. Very nice heirloom! Thanks for posting.
     
  18. Manitoba Man

    Manitoba Man Copper

    Lovely work sir.
     
    Melterskelter and DavidF like this.
  19. Zapins

    Zapins Gold

    Did you preheat the shell for this pour or just pour into cold shell?
     

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