Its a good start and I'm glad to see that you have finally gotten your printer in a working condition. Without know exactly which kind of printer you built I would assume that it is a Prusa or Mendel variant with a moving Y-Axis print surface (i.e. your glass or aluminum print bed). I found the same troubles with heated aluminum / kapton printbeds. They were not the most reliable and were, for the most part, too heavy and limited my print speed in the Y direction. I have since moved to simple plate mirror glass (1/16" or 1.5mm) w/ a MKI heated bed @ 65-55C. I really like this setup as it is VERY lightweight and has worked reliably for nearly 6 months. I typically print with PLA and have experimented with the new wood/PLA filaments with great success.
I don't see much reason to go with heavy 4mm plate or borosilicate glass unless you are printing with ABS which necessitates higher temps. I have never needed to take my print bed above 65C and so I reserve judgement on whether or not 1.5mm glass can reliably take that kind of temperature without breaking.
Good luck, let us know how you progress.
