I printed a 1:1 model of my mark making tool on the upbox printers so I could get an understanding of:

- How the tool fits and feels in my hand

- How the components of the tool interact with each other

- How the charcoal interacts with the tool

- How drawing with the tool feels 

I was impressed by how well it fit in my hand, the triangular form is a good base for my fingers to rest on and gives me the control I need. The Y shaped wedge that holds the 3 body segments in place works better that I had expected and is actually more important in the assembly process that I had anticipated. The internal grooves that grip the charcoal hold it well, although they will be soft when printed on the J850.

Below is a video demonstrating assembly and use (without the band which is yet to be printed)

After using the tool, I identified an issue with the tip, where the charcoal protrudes. Functionally, it has big corners that touch the paper when the tool is used on a low angle. Aesthetically, I feel it ends too abruptly, especially when contrasted by the thin charcoal. 

I tapered the tip to resolved both of these issues.

               Before                                                                                            After

I test printed 4 samples of the band with varying shore levels; 30, 35, 40 and 50. I was expecting the bands with low shore levels to be weak and the higher level to be too stiff to wrap around the tool but I was surprised.

Even the band with a 50 shore level was flexible enough to wrap around the corners and sit flush with the tool, but as you can see in the image below, it has cracks. 

The cracks were caused when I was stretching the bands, testing the elasticity of them. As you will see in the video below, I snapped the 50 shore band. Unfortunately it wasn't in focus but I didn't want to reshoot and break it again.

On closer inspection, I noticed that they were splitting from the sharp corners. I think they are weak because there is less material, so they won't stretch as much as far without breaking. Once there is a small split, it weakens the entire band so I will need to fillet those corners more to strengthen them.

Of the 4 samples, I think that the shore levels of 30 or 35 are the most suitable because the are flexible without becoming brittle and I think they are actually stronger considering that they need to stretch. The trade off for colour isn't really worth it because the difference between the 4 is so subtle that it is not worth sacrificing durability. I was thinking that although the band is essentially colourless, it is not a big deal as the transparency will allow the band to take on the colour of the rest of the tool. I could also embed coloured bodies in the band if I want to colour it, which may also provide grip. This is something I will be able to work through once I figure out the overall colour palette of the tool. 

The other thing I wanted to test was the mechanism that connects the band to the tool. The idea was that the inside of the tool is soft and that the plug was going to be able to push in past an opening in the hard shell and wedge itself into the hole which was cut to fit the plug. The diameter of the widest point of the plug was designed to be the same size as the hole in the hard shell but the fit was too tight and it didn't go in. I ended up breaking it trying to force it in. 

This made me rethink the shape of the plug, because there is a possibility that the perpendicular force of the band may shear the thin plug. Unlikely, because the force is so small and I put a lot of force on it to break it, but something to think about. Instead of using a plug, I might use a hook. This would make more sense because it will offer an apposing force to the direction that the band pulls. In theory, anyway.

I also wanted to test the hardness of the inside of the tool. I didn't want it to be too hard because I don't want it to scratch or create grooves in the charcoal as it slides out. I used a shore level of 60 and I think it was pretty spot on. I may even be able to go down to 50. I don't want it to be too soft though, otherwise it might allow the charcoal to move too much 

when im drawing and I also think softer material might wear away over time which is not ideal. 

I also wanted to test the one way movement of the "internal grips" I designed, which I hope make it easy for the charcoal to slide out and offer resistance when drawing so that the charcoal doesn't slide back into the tool.  

Below is a video of me testing it with charcoal and it appears to work but I may have been biased in how much force I was applying. This is something that I will need all 3 segments to test properly 

I also tested an idea I had, where using angled slices will hide and reveal colour depending on what angle the tool is viewed from. This didn't work very well, the angles were wrong and not spaced correctly to obscure the colour on the inside. My test print just looked like a zebra.

I also made the mistake of not using digital materials in grabcad print. I ended up with quite dirty, cloudy colours. Even the parts that were meant to be transparent were cloudy because I used the colour picker. 

In this next batch, i'm going to experiment to see if I can create some visual effects with the printer. The first is shown below. Front on, the surface appears black, but when it is viewed from an angle, the red underneath each ring is revealed. In the context of my tool, I will probably use wood rings or wood grain instead of circles. The idea behind this is that the tool is black like charcoal but when it is viewed from different angles, the colour underneath is revealed, as a nod to the wood the charcoal was made of. Woodgrain might be a bit corny, I might do something else.  

The second is the idea of using a lens to distort what can be seen. Instead of a lenticular shaped lens, I have created longer lenses. If this works, I will be able to run these lenses along the length of the tool. The brown to black is representative of the transition wood makes as it is turned to charcoal. 

For some reason I couldn't see through the transparent layer which is strange because I used vero clear. It printed black. I think it was because I printed it with the vero clear side down. It does have an interesting quality to it though, there is a sense of depth in such a small area which is revealed when it is held to the light. 

The lens print did work, but I made a mistake with the colours at the bottom layer of the lens. I chose transparent colours instead of opaque colours. Whoops. I also think the colours I chose are too similar to each other so the change viewing them through the lens is too subtle. 

It worked much better this time. I printed with the clear side up and I also instead of using vero black for the black parts, I used colour picker to get at opaque black. It didn't turn out opaque though but I suppose thats because it is so thin. As I mentioned earlier, I really like the depth and it is even clearer in this print.

I tried the lens again and I had a similar result. The bottom layers were red yellow and orange but the printer didn't get the memo. Thats ok though, I know what I want to do now but I'll write about it later.

I also tested another plug and hole section. This time I moved the vero further away from the soft hole so that it would allow the plug to go in. And it worked! Below is a side by side comparison with the first test. An accidental discovery I made was the pattern that was created by the printed layers. THEY LOOK LIKE TREE RINGS!!! This is the nice subtle nod to wood that I was looking for. For my final design I will be printing in the same orientation to make sure I get those rings on the surface.

The bad news is that the soft hole is too firm and it broke off when I tried to remove the plug from the hole. I could thicken the plug but in the spirit of being lazy, I am going to change the material of the hole to a softer shore level.

I spent a bit of time trying to decide what I wanted to do with the body on the pen. There is so much potential. I will already have the woodgrain-like surface texture thanks to the orientation of the build lines of the print, so I want to design something more subtle internally that sits below the surface of the tool.

I really liked the depth that was created with the red and black rings from the test prints. Even the one that "failed" made me think about how light can reveal something that is hidden below the surface. So, here is my idea.

I want to put this burnt, glowing wood pattern below a black surface layer, that should only be visible when held to the lights. Each of the burnt wood segments will protrude beneath the surface at different levels to create a varying levels of depth. 

This took forever to do and the pen now has over 400 bodies. So, the body segments essentially has 3 classifications of bodies. There are the protruding, black charred parts. The are the fiery coloured parts that sit between and below that charred parts. I split them into multiple bodies so that they will create a fiery effect. Then there is the black shell that goes over the top of all of the components to conceal them. 

I decided to print the final pen because I felt I had enough information from the test prints and I was also feeling the pressure of all of my hand ins. If I were to do it again, I would've done another test print of a section of this version of the pen because I ran into a few surprises. Not necessarily bad things, just unexpected. 

The segments are flexible, but they were supposed to be rigid. I did not expect this because my test prints were rigid but I think that was because they were short sections. Over a larger area, it was flexible, even though I used the black vero tray material for the shell. The shell is also quite thin and I suppose even thinner since I created the protruding parts beneath the shell. On a positive note, i'm glad this happened. Individually, the three segments that make the body are rather flimsy, but when they are bound together together by the band, they are strong! This is what I wanted to achieve with my tool, especially when I consider the ancient tools in my precedents. To be honest, I think I lost sight of that on the way, and I'm glad that this reminded me. When I started this I asked myself how can I use this super accurate, half a million dollar printer that prints using microscopic droplets to create something with a sense of crudeness, that won't always behave in the way you'd expect. Of all the sophisticated ways I could've held this tool together, I used cordage like a caveman! That was a bit of a tangent, hope you're enjoying this. 

I got a bit of colour on the inside of the segments but on the outside there is no colour at all. Where the vero black shell met the colour underneath, it just went black. There isn't even colour when its held to the light. I was a bit disappointed when I first saw this but only because it wasn't what I expected, but to be honest I like it better. I was going for subtlety and that is what I got. I also like that there is a clue along the edges of the segment that the inside has colour and that when you open up the tool the colour is revealed, which I suppose is unexpected when you're looking at the black shell (see image below) and look at those woodgrain-like rings!!!! Beautiful. 

This one was the colouring of the band. I was feeling a bit bummed that I couldn't get more colour into it without losing flexibility. I knew how the colour was going to look from my test prints but it wasn't until I did the final print and had it finally wrapped around the black tool that I realised how well it fits. It almost has this yucky sinew, raw hide look to it which fits perfectly with the tool, except no animals were (directly) harmed in the making of this pen.