Filament joiner for multicoloured 3D prints

I wanted to print some multicolored prints but wasn't sure how. After doing some looking around on the web I found a filament joiner on thingiverse. It used a milled aluminum block and a resistor cemented into a hole using heat resistant cement. This seemed like a lot of work and I don't have a mill so I thought of using a ceramic hair straightener to do the same job. After setting up the straightener with a gap just large enough to fit the filament. I could join the two pieces very easily. When