[techhelpbb]

What Stinglikeabee said plus:

Please be aware that the MakerBot Replicator 2 prints PLA. MakerBot's PLA. Not ABS. Do not extrude anything else unless you want to deal with the MakerCare support issue your group is opening the door to. MakerCare is not a warranty. It's parts replacement agreement you can only use once you precisely follow the directions MakerBot provides you. Those directions can take many hours to follow and there are no estimates for the durations of any of the repairs.

The extruder assembly is several hundred dollars on the Replicator 2.
It's very possible for other extruders to be half that cost.
If the extruder does not work you are not printing anything.
So if you really have issues with the MakerBot extruder expect to potentially be looking at $500 to entirely replace it.
The hot-end alone is around $200.

I can not recommend altering the extruder on the MakerBot because again you'll pretty much be throwing away your MakerCare and MakerCare alone costs $500. For that $500 you could build an entire printer. So if you have a MakerBot if you really want to use other materials then you should build another printer. Don't spoil the pot or else that printer you probably stretched to afford might just get even more expensive.

Keep in mind that this technology is quickly evolving. There are 4 extruder printer designs out there. There are filament mixing systems that can use a single extruder and hot-end with multiple filaments. Committing to whatever today's technology is might impact funding future opportunities for the next generation of printers which will come.

PLA is rigid but more brittle unlike ABS which is more flexible and for FRC part purposes ABS is more likely to survive bending without cracking on a wearable component (it wouldn't matter on say a decorative cover). Since there is a tolerance at work here you'd be better off with ABS flexing than PLA cracking unless you can glue the resulting damage easy enough.
Be aware that PLA better holds the dimensions of the print but if you are planning on acetone washing or sanding the part that's not relevant anyway (measure twice cut once).

There are lots of other filament materials for the RepRap style extruders. MakerBot sells lots of PLA filament colors.

Please keep in mind: generally 3D printing ABS/PLA is slow. Team 11 just printed a smartphone shaped item laying flat on the bed of their Replicator 2X. It is merely 3/8" tall and it took 2+ hours between setup, printing and cleanup. Going to make wheel hubs at 1" thick laying flat on the bed? The wheel hubs probably take up more surface area on the printer bed and are taller that that smartphone print. Consider the time involved and that it is probably not wise to leave a heated printer unattended. Going to move the printer if you run out of time? Then you need to consider that you are interrupting the print and risking the print quality plus if you move the printer you need to level it again. I know that if I need to print anything large I sleep next to the printer in a ventilated area with fire alarms and my phone alarm to wake me up every once in a while.

With delays like this owning a single printer might be someone's undoing.
I personally own a SoliDoodle 3 (RepRap style printer) and an Up! printer.
I use the SoliDoodle 3 (which I heavily modified) for most things.
I reserve the Up! for sensitive things or overflow production capacity.
I have parts for at least 7 Prusa printers laying about.

I support the idea that this technology should teach a person to fish. Not give them a fish.
I would rather my students learn to build a cheaper printer they can keep at home and use on their schedule:
than create consumers that know little about their printer than if I click >this< button it 'usually' works.
The promise of the RepRap project is a printer in every home for anyone that wants it.

To extend my last point: what impacts students more? A laptop they can do as they please with or a desktop at the school everyone is afraid they might break and there are 100 students in line to touch? This is about creativity and access to enable that creativity.