Prepping Before Painting?

Discussion in 'Miniatures and Scale Models' started by NNascati, May 3, 2019.

  1. NNascati
    NNascati Member
    I've ordered several models from Brown Water Navy in the "White Natural Versatile Plastic". Does this material need to be washed before I can prime and paint?
     
  2. Roolz
    Roolz Well-Known Member
    I'd highly recommend it (soapy water, toothbrush+elbow grease, rinse, let dry).
    There is sometimes (but not always) a bit of remaining nylon powder in the recesses, which literally drinks the paint.

    The SLS platic (Versatile plastic) naturally drinks the paint, since it's porous. So it typically requires more primer coats than other materials. But any remaining nylon powder makes it worse.
     
  3. NNascati
    NNascati Member
    Following Matt's suggestion, I scrubbed them with a dry toothbrush to remove any sediment, and then white primed. I had no problem at all painting them.
     
    Roolz likes this.
  4. Roolz
    Roolz Well-Known Member
    OK !
    As I wrote, washing/scrubbing SLS parts (White Versatile) is not always necessary.
    It highly depends on the geometry & size of the model, and of how the post-printing cleaning has been done by Shapeways staff (it's a manual process).
    Sometimes a model has about zero remaining nylon powder and doesn't need washing/scrubbing, sometimes another does.
    I for one always stay on the safe side, and wash :).

    Anyway, as you noticed, once it's correctly primed, SLS nylon paints almost as regular injected plastic (barring the roughness and porosity).
     
  5. stancilj
    stancilj Member
    You Tuber said cure pieces under UV 25 light before painting. Anyone else heard of that? JS
     
  6. Roolz
    Roolz Well-Known Member
    UV post-curing is relevant for UV-curable photopolymers (~resin). Totally different from SLS nylon.
     
    stancilj likes this.
  7. southernnscale
    southernnscale Well-Known Member
    I agree with all! I have just used hot soapy water! clear with a stiff paint brush since I'm working with a 220 scale models. I fine some of the chemical for cleaning dries out the plastic and the plastic become brittle. A tooth brush could break of details and If you have working parts best to run hot tap water over the area to loosen up wax build that gets trapped in side then before trying to use to much force and break it loose! I do that with my wheels on my semi's! I've heard some have used a ultrasonic jewelry cleaner also works well! I always let them sit for a day or so before priming with Fine Surface Primer for plastic & metal by Tamiya white color brings out the other colors better. I have gotten some models that have come with some hard crust on them and had to be careful when scraping it off it was really hard to remove even after cleaning mess up some of the details. Have fun. maybe some day they will find a better way to clean where there isn't so much work being put in!!!!!!