Roger Leung, of Monki Maker, has a great writeup on making Worbla and Wonderflex smooth for paint.
The Wonderflex/ Worbla texture problem
This post is about how to rid wonderflex and/or worbla of the bumpy texture. Everything reported in this blog post was all tested out by me and is not meant to be a end all be all solution. If you to find something better, then PLEASE do share it! The cosplay community is HUGE and always looking for new great techniques to make stuff, so please do give back!
The most popular ways of ridding wonderflex and/or worbla of the bumpy texture seems to be coating either material with layers upon endless layers of either gesso or a wood glue mixture or what have you. Yes those techniques do work, but they take waaay too much time! Application, drying time, application, drying time. x498,713,987. I know cause I’ve done that too. I’m not saying its wrong, but there has to be a better way, so, I experimented with ‘Filler Primer’.
I’m not the first person to do this, but I do not see it posted really anywhere on the web. So here are my results:
Grabbed some scrap wonderflex and worbla. Made sure I had tests with curves and not just flat samples. There are 4 sets because I wanted to test the smooth side and the bumpy sides.
The 4 sets of samples with ONLY 3 coats of Filler Primer. Each coat applied when previous coat was dry to the touch. Around 20 mins or so.
This is how things looked like after using some 100 grit sandpaper and doing some light sanding.
Wonderflex onthe left, Worbla on the right.
As you can see from the pictures, Filler Primer does indeed work to fill in gaps. Of course you can spray on more coats as this will not take up a lot of time, but DO MAKE SURE you are aware of the temperature where you are. I think on the back of the can, it says for the best use is starting somewhere in the 50 degrees range, so treat it like if you were using spray paint. Too cold and you will just get cracks and what not.
If you made something with complex curves and something with a lot of details, then I will suggest using only the filler primer.
If you may have noticed, when using wonderflex for complex curves, the fabric grids tends to act like a fence, causing the plastic to bulge out. That will probably take a lot of layers of filler primer to fill but if its complex and hard to get to when sanding that might be the best option. Now if you do get bulging in bigger spaces, I recommend using ‘Super Heavy Gesso’. It’s basically a paste form of the thinner gesso you mostly see at craft stores. Super Heavy Gesso can be found at art supplies stores. I have not seen any sold at craft stores. I.E. Michaels, Joann’s. If you do get some, I also suggest a palette knife for application. I would not use a brush as it makes application streaky and varies in thickness.
Below are pictures of the Super Heavy Gesso with Filler Primer method. Piece is coated, waited for Gesso to dry, then sanded with 80 grit sandpaper. Super Heavy Gesso is flexible and has a somewhat rubbery feel to it, which is why the heavier grit sandpaper is needed. You do not need to apply a lot of pressure when sanding the Super Heavy Gesso and you do not need to get everything really smooth. The Filler Primer will take care of slight bumps and holes. Notice how things are not completely smooth and somewhat bumpy. NOTE: If there are any deep holes, fill them in. The Filler Primer does not spray on thick enough fill in deep holes.
Piece is sprayed with 3 coats of Filler Primer. Notice the difference in the bumpiness!
Took some 100 grit sandpaper and did some light sanding to smooth everything out. When Filler Primer is fully dried/ cured, it sands really well, so you do not need to sand with a lot of pressure. If you are not satisfied and still want things smoother, go ahead and spray on more coats of Filler Primer.
If prepping for spray painting, you can probably spray one more coat of Filler Primer then sand everything down with 150 grit sandpaper and proceed with the spray painting.
I find the above method so much faster than applying 9,871,231,234,987,351 layers of whatever just to get rid of the Wonderflex/ Worbla texture. One other tip you can use to help speed things up is to flip the Wonderflex and/or Worbla around and use the smooth side instead. It works even better!
I hope all this helps speed up your cosplay making timelines.
With many thanks to Roger Leung, of Monki Maker, for sharing this with us!