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Casting - success at last

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  • Casting - success at last

    The first two pictures are of an attempt to do some Lost PLA casting (previous threads) and it shows an absolute failure. The sections on the top were to thin for the bronze to flow through and failed to form. There were some internal cavities that I have no idea what caused them. There was a cast in spider on the bottom, as shown in the first pic, that did form properly and would have been used as a temporary support for machining.

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    The next pics are of some casting made by my friend, "the founder", this morning and came out almost perfect. He used a more traditional sand casting method using petro bond instead of green sand. I printed the patterns (in blue), one was split and the other was a solid one sided pattern and they where molded in the usual manner. PLA printed patterns work well enough and are a lot faster and easier then making them from wood. Excerpt for a small flaw in the mould caused by sand coming loose they were perfect. This guy does some great work in his home foundry. He has built a 1/4 scale case traction engine doing all castings for it himself.


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    The odd shaped piece is the trunnion for a 1/2 scale 1906 Maxim machine gun and the round piece is the front water jacket cover. The trunnion is also the rear water jacket support. They are shown as cast.

    Doing it this way will mean more machining.
    Attached Files
    Last edited by loose nut; 09-13-2021, 02:36 PM.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

  • #2
    Looks great. Thanks for the update. Someday I'd like to try it..... some day.
    Southwest Utah

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    • #3
      Looks good!
      Paul A.
      SE Texas

      And if you look REAL close at an analog signal,
      You will find that it has discrete steps.

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      • #4
        I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days.

        Comment


        • #5
          Originally posted by RB211 View Post
          I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days.
          If you haven't already, check out VOG on you tube regarding casting and resin printers. By FAR the best source of info I've come across yet.

          Comment


          • #6
            Originally posted by RB211 View Post
            I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days.
            Any resin that can tack a little beating should be good. Molding a pattern does require some fairly significant pounding, not a hammer and smashing but still moderately heavy abuse. I use PLA filament which is brittle but still works.
            The shortest distance between two points is a circle of infinite diameter.

            Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

            Southwestern Ontario. Canada

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            • #7
              I've used elegoo black resin for sand casting patterns with great success. It holds up just fine. Only made a few castings from each pattern, but didn't notice any problems.

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              • #8
                Loose nut..So you used the PLA as a regular Pattern, and not as a Lost Pattern.. Correct ?

                Rich


                RB211- " I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days."

                Yes, I have PLA resin printed model(s) to cast as a Lost Wax type casting. The Artist shop for casting here in Green Bay is just opening so I haven't done that part yet.
                The stuff is expensive but magnificent material . The burn out is quite extensive with a stepped ( 4 ) heat and soak cycles and I had to get a controller for the kiln to do that .
                Here is a picture of some of the parts. The big gear is about 1-1/4" in Diameter and the tooth profile is superb
                Rich


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                Green Bay, WI

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                • #9
                  Originally posted by RB211 View Post
                  I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days.
                  afaik jewelry making via lost printed resin is a significant commercial use of these printers, so yes. There are resins intended to be burned out (as there for filament printers as well, but they're pricey compared to PLA)


                  Loose nut, glad to see the progress. Can you comment the bronze casting process? where did the bronze come from - random collection from around the shop or a specific alloy for casting, what's it like to cast, what did you do for a melter, etc. I want to try bronze and am curious how easy/hard you found it and what the tricks are.
                  in Toronto Ontario - where are you?

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                  • #10
                    Congratulations, nice job
                    mark

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                    • #11
                      Originally posted by Rich Carlstedt View Post
                      Loose nut..So you used the PLA as a regular Pattern, and not as a Lost Pattern.. Correct ?

                      Rich


                      RB211- " I wonder if they make a resin designed for this for the UV resin printers? Resin printers are my favorite go to these days."

                      Yes, I have PLA resin printed model(s) to cast as a Lost Wax type casting. The Artist shop for casting here in Green Bay is just opening so I haven't done that part yet.
                      The stuff is expensive but magnificent material . The burn out is quite extensive with a stepped ( 4 ) heat and soak cycles and I had to get a controller for the kiln to do that .
                      Here is a picture of some of the parts. The big gear is about 1-1/4" in Diameter and the tooth profile is superb
                      Rich


                      Click image for larger version  Name:	P5110010 A.jpg Views:	73 Size:	111.9 KB ID:	1961222 parts
                      Rich, my first try was the Lost PLA method but with the internal cavities the wall thickness's were to thin for the bronze to flow threw.Th PLA did burn out fine and the parts that formed looked pretty good for a first attempt. Since I now had to cast the parts without the internal cavities, I could have made another burnout pattern sans cavities, it made more sense to just use the traditional sand cast method. I think you have met Tony at NAMES and Cabin Fever. He is quite proficient at this.
                      Last edited by loose nut; 09-14-2021, 10:17 AM.
                      The shortest distance between two points is a circle of infinite diameter.

                      Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                      Southwestern Ontario. Canada

                      Comment


                      • #12
                        Originally posted by Mcgyver View Post

                        afaik jewelry making via lost printed resin is a significant commercial use of these printers, so yes. There are resins intended to be burned out (as there for filament printers as well, but they're pricey compared to PLA)


                        Loose nut, glad to see the progress. Can you comment the bronze casting process? where did the bronze come from - random collection from around the shop or a specific alloy for casting, what's it like to cast, what did you do for a melter, etc. I want to try bronze and am curious how easy/hard you found it and what the tricks are.
                        The bronze was from old bearings and thrust washers and other old cast parts like deep well pump impellers. Industrial stuff nothing purchased for this.

                        The furnace he uses is the Gingery Little Bertha design but with gas not electricity. He can get up to just over 2200 DEG Farfrometric. This book can be found on the web. He casts aluminum and bronze but generally not brass because of the zinc burnout problem. Except for the crucibles all of his equipment is homemade and pretty simple, no need to get over complicated with this. He mostly uses Petrobond sand and some times a resin based binder, for cores, If you have cast Aluminum then it is basically the same but hotter, different fluxes ETC.

                        P.S. the PLA patterns held up fine and I could use them many times if necessary.

                        P.P.S. there is a wax filament that is made for printing lost wax patterns, available from filament suppliers. I'm not familiar with the print methods or if it is done differently.
                        Last edited by loose nut; 09-14-2021, 07:47 PM.
                        The shortest distance between two points is a circle of infinite diameter.

                        Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                        Southwestern Ontario. Canada

                        Comment

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