Using my 3d pen to weld parts together

 Ok so I was cleaning out my shelf and found a 3d pen I had from a while back.  I think I got it on Woot.com or something like that for super cheap.  They go on clearance at places like Michaels and JoAnn craft stores as well.  Amazon sells a bunch and recommends this one.  Mine is similar, but I don't think it's manufactured anymore. 

So what I didn't realize when I bought it is it uses the same filament as my 3d printer.  It makes total sense now, but I didn't connect the dots at the time.  I put my 3d printer filament in it and it extruded great! which gave me another idea - could I use it to repair, weld or fill a 3d print.  

The short answer is YES! I took two calibration cubes from my 'stuff I printed but is totally useless' box and tried to weld them together.  It worked pretty good!  I would need a lot of practice to get it smooth and neat, but it does work. I also filled in the X, Y and Z recessed letters to see how that would go and just like the weld, I need to practice and I think go slower - my pen has a variable feed rate to help this. I think it'll come in handy for some very specific use cases.

Anyway if you have a 3d print that you want to melt a little more filament onto for repair or aesthetic reasons, these 3d printing pens are a fun and relatively cheap way to go.