Epoxy wouldn't be a good material for a long, unsupported beam like that, even if filled with glass fiber. A cast iron sewing machine arm isn't going to eventually sag under its own weight, though it may not be shaped to withstand horizontal bending and longitudinal twisting forces without some deflection. Fill it up with epoxy and chopped glass and it should become stiff enough for hanging a wood routing spindle on the free end.
This guy had an epoxy slab cured for 18 months yet in the sun it still easily bent. https://youtu.be/hCmE2yY8Kvk?t=619 On Saturday, May 20, 2023 at 01:14:47 PM MDT, Chris Albertson <albertson.ch...@gmail.com> wrote: If you are going to the trouble of filling a frame with epoxy then two things… 1) Why bother with the frame, just print a plastic mold and fill that. with epoxy. Then it will be the exact size and shape you need. 2) Don’t use epoxy as it is not very stiff, Mix the epoxy with glass fiber such that the fiber-to-epoxy ratio is as high as you can possibly make it. You don’t need expensive carbon fiber as you don’t care about weight. You want as much glass in the mix as possible. The usual way is to use woven glass, wet it with epoxy then use pressure from clamps or a vacuum pump to compress the part and push out as much epoxy as possible. But you can also mix chopped fiber with the liquid resin and make a paste. This is actually very low-tech and can be done with simple hand tools like paintbrushes and scissors. The problem is the same as with any new design, you have to make some prototypes and measure them and likey redesign them a few times. This is why people usually copy existing proven designs. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
