NinjaFlex iPhone Cases, Snowflakes, Skulls and Valves

by Jason King on November 30, 2014

3D Printed Dry Brushed SkullSince discovering Dry Brushing a few months ago and having my first spool of NinjaFlex Filament delivered I’ve been doing a lot of experimenting with both of these.

Dry brushing is a great finishing technique for highlighting detail on 3D prints and I’ve been discovering what works well and what doesn’t.

I think silver guilders paste brushed onto a darkish print works best. Dark guilders paste on light prints just makes them look dirty and isn’t something I’d recommend. More on this later. As for NinjaFlex, I’m continuing to test and tweak my settings to create better prints.

As it’s still a little stringy when bridging gaps I find it works best with solid objects which lack detail. Eg, a solid cube has no gaps to bridge and would print perfectly. Raised lettering on the other hand is full of gaps and might just create a stringy mess.

Custom NinjaFlex iPhone Case

NinjaFlex iPhone Case BottomIn my quest to raise awareness of my website using Facebook advertising I have noticed that iPad stands and iPhone cases are very popular. It seems that people like the idea of creating custom accessories for Apple products. Not sure why this is, but they do.

That brought me to the idea of combining Apple accessories with NinjaFlex, in the form of custom rubbery iPhone cases.

This is my first attempt at 3D printing an iPhone 4s case using NinjaFlex, which I’d previously designed and printed in PLA for my friends wife. The original PLA version turned out well, but it was quite tight and with PLA being quite inflexible it wasn’t a great fit.

NinjaFlex iPhone Case TopThis NinjaFlex version turned out quite well and due it’s design and the tool path used by my MakerBot wasn’t too stringy and didn’t require much cleaning up afterwards.

Unfortunately though the design is meant to be printed in hard plastic and by it’s very nature, it just won’t stay on the phone when printed in NinjaFlex.

I anticipated this might be an issue before I started so I used 50% infill rather than 5% to increase the stiffness. It wasn’t really enough though so although this case printed really well, it’s not very useable. I just need to find a new design to customise which will stay on the phone better.

3D Printed Snowflakes

When Halloween was approaching I nipped over to Thingiverse to see is I could find any Cool Pumpkins to 3D print. That was a success as I found a great design and make three, so I’ve just done the same but with the festive season in mind.

3D Printed SnowflakesI found a cool little snow flake which can either be printed flat (as snowflakes generally are) or with a slot so you can slot two together and make them even more 3D. I opted for the latter and printed out a few.

When printing the first snowflake I thought it was quite interesting to watch. The more intricate shapes are great to watch, because you can watch your printer draw the complex outline and then fill it in, just like you might color it in if you drew it yourself on paper.

The best way to demonstrate what I mean is to actually show you so I’ve included a short 20 second YouTube video of it printing so you can see exactly what I mean.

After printing this white one I took it into the office and although it’s not the most impressive 3D print I’ve ever made, it drew quite a bit of attention. After printing a few more for myself and for other people I also made one in natural (clear) PLA so it looks more like ice.

Simple but quite festive I though… oh and I just realised that they’re all now either at the office or I’ve given them away to people, so I’ll have to gather some together and take the photos later.

More Cool Celtic Skulls

Large 3D Printed SkullOut of all the things from Thingiverse that I’ve downloaded and printed, the Celtic Skull is one of my favourite objects. At the last count I’ve made five of these, starting with the Full Size Green Celtic Skull I made months ago.

The other day I was working away and thought to myself that my MakerBot shouldn’t really be just sat there doing nothing, so I printed another skull in my favourite filament, ColorFabbs fluorescent green. I mentioned these skulls to a colleague who asked me if I’d make him one.

He’s interested in evolution and how the human brain works so he said he’d like one. I’m not sure these are an accurate representation of a real human skull, so I wouldn’t really be using them for medical training or anything like that.

However, I printed a small blue one and dry brushed it using silver guilders paste to highlight the detail. To be honest I thought it looked so good that I didn’t want to give it away, so I immediately started printing another, before my MakerBot even had time to cool down from the last one.

I’ll show him tomorrow to see if he likes it. If not, I’ll get to keep it for myself, which I’m ok with.

Fixing a Broken Balloon Valve

Something I noticed recently is that out of all the 3D prints you see on Twitter, Facebook and elsewhere, the vast majority are ornamental, with most of the rest being new functional objects.

What I never seem to read is anything like this…

“Yesterday I broke my [any random plastic item] so I used my 3D printer to make a new one!”

Fixed Balloon ValveSurely one of the advantaged of owning a 3D printer and knowing how to work simple CAD software like Tinkercad is that you can fix/replace things that you or other people break. I honestly can’t remember ever reading about someone doing this. I’m sure they do, but it just seems so uncommon.

Well, I saw my opportunity the other day when my girlfriend accidentally knocked over a helium tank and shattered the plastic valve which is used to inflate balloons (it’s a long story).

Out came the vernier caliper and a few measurements, ten minutes designing and one discarded prototype later we had a new perfectly functional valve and balloons were being inflated again.

Finally a functional use for my 3D printer! It’s just a shame that I can’t fix the dent in the laminate floor that the valve made when it hit it.

Anyway my girlfriend said that next time she goes to the wholesalers she’s going to take the new valve with her and show them, to see if they want me to make them some. I’ll let you know what they say.

2D Images to 3D Models

In my ongoing quest to create 3D prints from 2D photos and sketches I’ve been making more stuff from simple designs made using a pen and a piece of paper.

As I can’t draw anything well, I asked someone else to draw something for me. Hence the treble clef, apparently it’s a music thing.

Given this drawing on paper, this is what I then did next to create 3D prints from it:

  1. Scanned in the image using a flat bed scanner. A photo of it would work just as well.
  2. Imported the image into Inkscape which is some free software I downloaded.
  3. Selected the image and then clicked on “Path -> Trace Bitmap…”.
  4. In the new dialog box tweak the “Brightness cutoff” and “Edge detection” if you want.
  5. When you click “OK” an SVG file version of the image is created.
  6. Repeat the tweaking and creating if you need to until you see a good SVG image.
  7. Click on “File -> Save as…” and save the file as an SVG.
  8. Pop over to (also free), create a new project and import the file.
  9. Choose a Scale (20% works well) and a Height (5mm to 10mm is good).
  10. Now you have your 2D sketch as a 3D model which you can export as an STL and print!

2D Sketch to 3D ObjectAs you can see from the picture (the original sketch is in the middle) I created a 3D print from the sketch in Dutch Orange PLA and then a slightly bigger one in black NinjaFlex. Both turned out quite well.

I really like this technique because it’s so simple and it means that anyone can draw something on paper and have it 3D printed. As I write this I’m also working on a technique for creating Lithophanes.

Many years ago these used to be made from thin translucent porcelain and when light was shone through them you could see an amazing picture.

Of course now I have a 3D printer I’m not going to be etching away at porcelain. I’ll explain the modernised technique in a later blog post when I’ve perfected it myself, but initially it looks great and is another cool way to create customised 3D prints for people. You could even use it to Earn Some Money from 3D Printing.

Please Like and Share this article then Download your FREE eBook: Beginners Guide to 3D Printing at Home.

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{ 2 comments… read them below or add one }

John December 7, 2014 at 8:00 pm

What a great response to my query about real costs of 3D printing.
This is amazing considering all the makers of 3d printers I’ve contacted couldn’t/couldn’t be bothered/just plain didn’t care or know how to get the info had no clue how to relate volume to actual print size or any sort of time scale whatsoever. This young man has taken the time to answer these questions in a very reasonable way that a layperson such as myself can relate.
I look forward to reading more on your website from now on and will spend much less time being frustrated and misled.
Thank you very much


Jason King December 9, 2014 at 10:00 am

Hi John,

I think you meant to put this comment on this post: but never mind 🙂 If you wish to post it on there too feel free.

Anyway, thanks for your comment I really appreciate it. My 3D printing costs post did take a lot of effort but I thought it was necessary to address a question, which lots of people ask but no-one seems to have an answer to.

I hope you and other people find the post and the cost calculator useful.

Many thanks for reading.


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