Gunderson Auto-Max

minzemaennchen Jul 16, 2020

  1. minzemaennchen

    minzemaennchen TrainBoard Member

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    A project I have started years ago, but stopped because I couldn't find a satisfying solution for the bellow between the cars. Well, still no solution, but some ideas, stay tuned. At least I have finished the metal etchings part of my prototype.
    If you look straight from the side the missing bellow is not that evident. Massive car, 200mm long and 30mm high, pretty big fellow.
    [​IMG]
     
    ZFRANK, Kez, gmorider and 4 others like this.
  2. rray

    rray Staff Member

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    Why not just use black polyester fabric, like from a black bandana. It's light and flexible enough, and you can make U shaped wire clips to hold the strips in place from the inside. If the prototype has ribs or a bellows shape, you can simulate that effect by drawing lines on the fabric.
     
  3. minzemaennchen

    minzemaennchen TrainBoard Member

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    I tried some fabric and foil stuff, looks alright on the straights, but just moves out of place in curves, don't like it. I have some flexible resin for my 3D printer coming and give it a shot for a proper bellow
     
    bostonjim likes this.
  4. LWR21

    LWR21 TrainBoard Member

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    Can rubber sheeting be laser etched to form the corrugated look of the bellows? The cars look amazing.
     
    bostonjim and minzemaennchen like this.
  5. rray

    rray Staff Member

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    Yes, you can use a laser to make and actual bellows. You would have to use absolute position or home mode on the laser profile, raster the bellows profile then cut out the part, flip it over then raster the other side.

    Absolute Position Mode or Home Mode causes the laser to start the engraving at exactly the same starting position so both sides overlay properly.
     
    bostonjim likes this.
  6. Doug A.

    Doug A. TrainBoard Supporter

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    Nice work Gerd, as always. :notworthy:

    Athearn's N-scale model just uses a hard plastic piece that sort of "floats" over the truck bolster. There is a nice isometric drawing included with the model to show the parts. Might give you some ideas.
     
    bostonjim likes this.
  7. LWR21

    LWR21 TrainBoard Member

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    Thank you for that, Robert. Would the laser change the properties of the rubber in any way, or is the exposure so limited that it's not a factor?
     
  8. shortpainter

    shortpainter TrainBoard Member

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    Fantastic job on the Auto-Max!
     
  9. rray

    rray Staff Member

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    To be honest I don't know how long it would last. I just know that I can make rubber stamps with the laser.
     
  10. SJ Z-man

    SJ Z-man TrainBoard Member

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    I think more of the problem of compliance as the cars wobble (independently) as ‘side-swipe’ with no transition track to curves. That’s tall, really tall, and I can tell you that the 34 Autoracks I’ve run probably aren’t going to like something restricting their movement.

    but they look freakin awesome!
     
    bostonjim likes this.
  11. bostonjim

    bostonjim TrainBoard Member

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    That must look impressive. The bellows seems like a detail that can be left out if it is going to cause derailments. I wouldn't want to keep putting them back on track. I would just pretend they were there. Jim
     

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