Printing a thin overlay with details

Discussion in 'Design and Modeling' started by SPCM, Aug 27, 2013.

  1. SPCM
    SPCM New Member
    Hi,

    Shapeways support suggested I post this question here:

    One of my long due project is to make model railroad tank cars with rivets pattern. Due to the required round and smooth surface along the tank, printing the car body is not an option (for now anyway). However, I was wondering if printing a thin wall with the appropriate rivets and overlap seems could be wrapped around a brass or plastic tube. I model in 1/64 scale so that would be an inch or so in diameter. The sheet size would be around 4" x 6". I would use the Frosted Ultra Detail material (printed at minimum thickness). The question is, could it be wrapped around a 1" diameter tube without braking? Maybe with gentle heat from a hair dryer to soften it up?

    Thank You

    Simon Parent
     
  2. AmLachDesigns
    AmLachDesigns Well-Known Member
    Why is that?

    If you are proposing to print a flat sheet and wrap it around a tube, I think it would break. But if you are proposing this, why not just build the curve in from the beginning? Which brings us back to my first question.

    Good luck!
     
    Last edited: Aug 27, 2013
  3. SPCM
    SPCM New Member
    The reason I would not consider (yet) printing the entire car body is because vertical layers with a 0.0016" thickness (UFD) would show up on a round surface. I know it could be sanded but because there would be vertical and horizontal rivet patterns (It would be WWII era car), sanding between the rivet patters could be tedious but maybe feasible with patience.

     
  4. FreeRangeBrain
    FreeRangeBrain New Member
    Assuming you're up to the challenge...

    Print the tank skin as you propose, observing the minimum print thickness. Coat the skin's textured side with a suitable release agent. Place the skin on a very flat surface, texture side up, and cast a medium-hard epoxy over top (and beyond the edges - you will likely cast into a box-shaped form for this) as a backing plate for what follows next. Once cured, place the cast assembly on a belt sander or other suitable grinding medium or tool and grind both the exposed skin (back side) and surrounding epoxy backing plate rim until the skin has acheived the desired thickness. I highly recommend taking a LONG time using light pressure and checking often for even removal over the entire surface. It is also be possible to do this by hand on sand paper and a flat block or plate, which would perhaps better facilitate both reduction of grit size as the desired thickness is approached and better control over the process. Be sure to keep the part cool at all times! The FUD will flex if made thin enough, but it may only be wafer thin by the time it does. Be extremely careful when releasing the skin from the backing plate as the skin will be quite fragile. (This may be the critical factor in choosing what kind of release agent to use.)