Here's all the modifications I've made to my Solidoodle 2 (and it is a good thing one of my goals when deciding on a 3D printer to buy was to get something I could tinker with, because there has been a lot of tinkering :-).
A Glass Bed and hairspray was the first mod because I couldn't get anything to stick to the stock Solidoodle bed. This was an enormous improvement.
The Z-Stop really needs to be replaced to use a thicker glass bed, and this version of a replacement Z-Stop also allows the use of locktite to keep vibration from changing the Z-Stop setting over time.
The Spool Mount allows the filament to be dragged into the extruder with much less resistance than the stock mount which runs the filament though a hole from the back.
The Foamboard Case (with vinyl windows) has gone through several iterations (most recently to extend the front cover to allow a fan to poke out), but the latest design for the clips and magnets to hold it on has definitely improved since my initial case.
The 12 Volt Power box to add a bunch of 12 Volt headers for extra fans and wot-not was useful. Since it uses a separate 12V supply, I can unload fans and LEDs and such from my printrboard and let the power go to things like the print bed heater and extruder (not that it really makes a lot of difference).
The Electronics Cover keeps the printrboard cool with dual 40mm fans.
The Nema14 Fan Mount was handy for cooling the X axis stepper (which seems to get pretty darn hot without cooling). Had to do a little filing and scraping to get it to go on, but I no longer get blisters if I happen to touch the motor after a print :-).
The Nozzle Cleaner allows me to run the hot end across a pipe cleaner to remove any filament that drooled while the print head was heating up before the print starts.
The Thumb Screw from thingiverse (flat version) was useful to let me easily adjust the bed level (I epoxied them on as they would just unscrew otherwise).
The Stabilizer helps keep the print bed from vibrating when the carriage movement hits a resonant frequency (or the print head drags across curling up plastic).
The New Z Axis seems to work and fixed a problem I always seemed to have with what may have been a damaged thread (it always showed up at the same level).
The new Y idler brackets seemed like a good idea to provide a more solid mounting for the use of fishing line instead of belts.
The Y rod bearing also stiffens up the Y rod for the potential higher stress fishing line.
The Fishing Line Conversion replaces the belts with fishing line to reduce backlash.
New Carriages to provide all linear bearing motion.
Y-Rod Direct Drive gets rid of the nasty belt that is the source of much backlash.
The Cable Chain should help to switch to the E3D since I'll have more fan cables and new heater and thermistor cables to run to the motherboard.
The PWM Fan Mount helps keep thin layers and bridges from curling up.
The Bed Heater is a modification in progress. I have added all the missing headers to the printrboard (one of which is being used for the PWM controlled fan above), but I haven't yet gotten the extra power wired into the board or fully switched to the new power supply.
Go back to my main Solidoodle page.