Filler for cardstock seams

logging loco Mar 2, 2021

  1. logging loco

    logging loco TrainBoard Supporter

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    I'm going to build an old N scale Railhead Grainery kit. It represents a small cast concrete grain elevator and silos.
    Looking for recommendations for filling any small gaps at seams in the cardstock building.
    I plan on spray bombing it light gray primer prior to assembling then painting and weathering after assembly.

    Thanks in adavance!
     
  2. micktropolis

    micktropolis New Member

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    This may or may not help, but I have a 1/72 Revell Space Shuttle model kit that I've been adding a skin of tiles and textured cardstock to. Around the nose and cockpit I cut the cardstock into squares, mounted it to the model kit with super glue, and gaps were filled using Vallejo Acrylic Plastic Putty 20ml tube (not the bottle). It can be smoothed with a damp paper towel or finger. In the photo below you can see the white seams next to the cardstock, that's all Vallejo putty. If you use a lot of it to fill a big gap it will shrink, but I find it very easy to work with!

    [​IMG]

    And it paints well. This is after priming and paint with Tamiya primer and white.

    [​IMG]
     
    Kurt Moose likes this.
  3. Rockfish RR

    Rockfish RR TrainBoard Member

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    I like the tube Vallejo Acrylic Plastic Putty... it’s easy to work, clean etc...
     
  4. logging loco

    logging loco TrainBoard Supporter

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    Thanks!
     
    micktropolis likes this.
  5. sd90ns

    sd90ns TrainBoard Member

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    First, and before installing the windows and doors, shoot it with a couple of coats of "Filler Primer", this will give some texture to the walls and seal the cardstock so it won't absorb any water.

    Then take some Elmer's wood filler and go to town. If the cardboard tubes have spirals then thin the wood filler to the consistency of mustard and apply along the lines. Allow to dry then sand until smooth.

    This is a trick model rocketeers use to fill the endless lengths of spirals in the cardboard airframe tubes.
    Done right you can get a great finish.

    [​IMG]
     
    Pastor John likes this.
  6. logging loco

    logging loco TrainBoard Supporter

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    Belated thanks sd.

    Nice looking rocket you have there.
    My foray into rockets as a kid was short and less than successful! I might have to try again.

    I've got some Elmer's wood filler. Hopefully it is still soft. I'll try it on building corners.

    I wrapped the tube in sheets of paper included in the kit. I used Elmer's glue stick to adhere it. I'm curious to see if the paint solvents will lossen the glue.

    I'm not too worried about the tubes. If anything goes wrong with them I'll replace them with some ¾" PVC.
     
  7. Shortround

    Shortround TrainBoard Member

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    Please keep us informed. This is getting interesting and informative. ;)
     
  8. logging loco

    logging loco TrainBoard Supporter

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  9. COverton

    COverton TrainBoard Member

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    I am late to this, but I would think that spackle would do, the 'exterior' quality stuff. Maybe Durham's Water Putty in a pinch, but also caulking that can be primed before painting (otherwise it will still show through the paint as a lighter streak).

    I haven't tried any of these, but I can't see immediately why none of them couldn't be used to good effect if some care is taken. The wood putty/filler would be a pretty safe bet if one can get it readily (which shouldn't be a problem at one's local hardware).
     
    BNSF FAN likes this.
  10. logging loco

    logging loco TrainBoard Supporter

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    Thanks COverton, your just in time actually!

    I primed the wall interiors today with a medium gray sandable automotive primer. Tomorrow I'll start gluing the walls up. In hind sight that primer May not seal out moisture.

    I have some Durhams Water Putty. If I remember that stuff gets rock hard. Which ever filler I use it will need sanding. Maybe I will get lucky and a light coat of bush on primer sealer will be all I need to fill the seams.

    The pieces are die cut so each edge is slightly rounded from compression. A couple have not quite straight edges. I may try pairing up the walls and give each edge a few light strokes on the sanding fixture before final assembly.
     
    BNSF FAN likes this.
  11. COverton

    COverton TrainBoard Member

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    I have found exterior grade spackle to do a good job on some repairs that I have done to wood joints. It needs to be fairly smoothly finished because it gets hard, not unlike the Durham's. But it can be sanded.
     
  12. logging loco

    logging loco TrainBoard Supporter

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    I glued sub-assemblies today. The gaps weren't too bad. I tried filling with brush on primer sealer but didn't like the results.

    I was not able to go to the cellar for Elmer's wood filler, don't ask. Durham's was within arms reach. In stead of water I mixed it with the primer to a peanutbutter consistency.

    I spread it on with a small sculpting spatula. It filled well and set up quickly. I have to go back and sand of the excess.
    20210321_225004.jpg

    I'll post some better photos tomorrow.
     
    BNSF FAN likes this.

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