How do you sand Strong & Flexible plastic that has texture?

Discussion in 'Finishing Techniques' started by KreativeKirk, Nov 29, 2015.

  1. KreativeKirk
    KreativeKirk Active Member
    I have a model that is being printed via Shapeways in Strong & Flexible plastic. I couldn't order in polished because it was too big for the bounding box. Images of my model are attached to this. He has a scaly texture and I know Strong & Flexible has a grainy surface, so I would like to knock all of that out and still have his texture intact. Anyone know what I could do exactly? Thanks!
     

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  2. DoctorOctoroc
    DoctorOctoroc Well-Known Member
    Unfortunately, WSF is grainy all the way through since it's built up from a powder base so straight sanding will just shave off layers of the same rough consistency. You can apply layers of varnish, paint, or some other sealant and sand that as it fills in the 'pours' but that won't work on your model unless you want to do some seriously detailed and time consuming sanding of every crevice of the intended model texture.

    There is a method that some have used that involves mixing superglue and acetone together, then submerging the model into the mixture to coat it, and removing it so the acetone will evaporate and leave a layer of superglue around the outer surface that will be relatively smooth. It still works better when you can sand after the fact and either way, you'll lose some finer details, but it may be your best bet. I haven't personally attempted this method though so you may want to wait for someone who has done it to chime in with advice and specifics on the ratio of acetone to super glue, etc.

    Others have used floor wax or similar compounds to work into the surface but again, these require sanding after the fact.

    If you're planning to paint it anyway, I've found that a few layers of paint and varnish alternated will smooth out the surface with minimal loss of finer details. Here's a model to which I applied two layers of varnish, 2 of paint, one of varnish, one paint then one last layer (or two, can't remember) of varnish. This protects the base layers of paint and smooths out the surface considerably. For frame of reference, this model is a 1:5 scale Wii U, about 10mm high - so if the scale is larger on yours, it will look that much better.

    IMG_4769b.jpg

    Truth be told, I didn't take much care in ensuring a clean work space or that the layers were super consistent, so you'll have better results should you be willing to put in the time where I was not.
     

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    Last edited: Nov 29, 2015
  3. KreativeKirk
    KreativeKirk Active Member
    The main reason why I wanted to kinda smooth out the model is because I'm going to be making silicone molds so I can make resin copy's and I'm afraid if I don't make it smooth, the molds will pick up the grainy texture.
     
  4. CybranKNight
    CybranKNight Well-Known Member
    The problem with that idea is that WSF is inherently porous, and while Silicone is thick it will still seep into a WSF model as it cures, ruining the mold and the print as well most likely.

    You can use stuff like bondo and spot filling materials to fill in those holes but it'll take a lot of applications and sanding to get the surface smooth, and it needs to be smooth because if it isn't the silicone WILL capture that that when you do try to make your molds.
     
  5. Shea_Design
    Shea_Design Well-Known Member
    After some great feedback and suggestions from experienced users I'll just take the heat and say it, in Shapeways parlance if I may try... you need FUD. That's a great looking model, and with your production plans you want the best prints possible. Is it a size issue?

    -S