3D Printed Stationary Holders: Combining PLA Colours

Above: Design shown completed with combined PLA

Challenge: To create a working stationary holder and for affect with the design to combine PLA colours to enhance its presentation.
Background: The majority of this point in the school year (in New Zealand we run from February until December so we are approaching the three quarter mark) of students in the classroom have at least one significant 3D Print which they are using regularly.  In this case the student wanted to combine colours for the base of the project to improve its presentation, by significantly combining two colours of PLA for effect.   The chosen colours as seen on the design to the left were the blue and the black.    The student printed the design in two main print runs, allowing the design to then be finished by having a super-glue applied between the layers which were then glued together.    The student had some experience working with others as part of 3D Printer design and projects and was able to complete this design as shown without any input from the teacher.   

Rear of design shown including incomplete printing

Level of Difficulty: Medium - the design was the students own, created by using the Tinkercad main interface to produce a series of basic shapes (rectangular prism, oval).   These shapes were then stretched to the desired level and he decided to personalize the project by adding additional features to it (including an owl and soccer ball on the reverse). 
Size: 120mm high, 110 wide/long and a total of 120mm across.   The walls of the design alternated between being 5mm and 10mm thick in places.    The soccer ball and the rear storage raised the design 60mm off the base.     The lettering of the students name was 5mm from the top of the design.
Time frame: The design took two considerable runs - the base (the blue PLA shown in the picture) was a fourteen hour effort.   The black which formed the final top part of the design took eight hours.   These dimensions could have been improved by reducing the thickness of the design in places and being consistent with the 5mm thickness.     For a print of this scope this is within the bounds of what would be expected (this was completed using a four and a half year old printer with a 8mm nozzle and a twenty percent infill setting).
What we would do differently/next steps for students: The student decided to go with a blue/black combination for the design, with hindsight a secondary colour would have had more impact.   The student should have probably printed the lettering for their name in a separate colour, however he chose not to.    Although the print looks correct with its dimension more time should have been spent using sandpaper to reduce the amount of PLA at the point where the prints were joined.   Having said all this the student was very pleased with the result.  He has still to complete the final aspect of the print which is to be put on the top of the soccer ball.   This is visible in the second picture on this print, the student increased the height of the soccer ball which compromised its shape, again something minor but could have potentially been addressed.