Well it seems Makerbot got a bit wiser lately and decided to have some of their new printers use a very specific spool size. Not surprising, you can only buy filament on this spool size from Makerbot (for now anyways...).
So whether you have the new MakerBot 5th Generation Replicator, Replicator Mini or the Replicator Z18, we're sure you've noticed that they all come with a filament drawer requiring a specific spool size; limiting you to purchase only the required spool sizes. Well luckily, there is a fairly simple solution where the filament does not necessarily have to be in the drawer...
Here's how we did it:
1. Place filament spool in a location where it can freely rotate. You can use a spool stand (such as http://www.thingiverse.com/thing:143424 or http://www.thingiverse.com/thing:283656) or a spool holder (such as http://www.thingiverse.com/thing:392784 or http://www.thingiverse.com/thing:437082)
2. Press the control panel dial.
3. When the Smart Extruder is fully heated, load the free end of the spooled filament into the loading tube at the top. Keep loading the filament until you feel the Smart Extruder pulling it in.
4. Once the plastic is coming out of the nozzle, press the control panel dial to stop extruding.
5. Wait for the plastic from the nozzle to cool before clearing it away and you're ready to print!