How to keep from running out of filament while printing?

I was wondering how I can prevent running out of filament in the middle of a print? And how to prevent filament waste..

Is it possible to pause a print job to swap the filament to a new roll to prevent from running out in the middle of a print?

I was also wondering if it is possible to solder or join 2 filament ends to make a longer spool of filament. This would help prevent filament waste.

 

Generally you can just watch the filament and as one runs out, feed the next one in by hand until it's grabbed... however, yes there are methods of joining multiple filaments together. Check out this page: http://richrap.blogspot.com/2011/06/multicolour-3d-prints-and-3mm-filament.html

 

Great link Matt. RichRap has a great blog with lots of quality info on it.