@landonator convinced me to buy him a 3D pen the other day. It came over the weekend and I've been messing around a bit with it.
I made sure it was one that could accept the 1.75mm filament used by my 3D printer so we have a good size selection of colors to pick from.
We used up the tester filament that came with it just messing around and making different shapes. I made @landonator a nameplate that he really liked and we made a little house that, because we ran out of red and had to switch to yellow, looks more like a garage.
These little things are cool when messing around, but not very practical in my opinion. What will make this pen useful is when household plastic breaks and needs to be put back together.
I've posted in the past about designing and replacing various things. Printing an axle to fix a remote control car or fixing my tonneau cover on my truck. Both repairs worked but they took a considerable amount of time to design and then print the whole object to be replaced.
My wife recently asked me to help her fix her cell phone holder in her car that had snapped. There was a weak point in the design and she wanted me to reprint the part for her. Glue wasn't holding it because it was too finicky to get the pieces to stay while it dried to get anything strong enough.
I didn't end up doing it because it was too time consuming and probably would have ended up breaking the same way so she just bought a replacement. The new one was made out of metal in the weak spot from the same company so they were aware that it was a design flaw. What would have fixed it easily would have been to just weld it back together using the 3D pen and build up a little bit of plastic around the weak spot.
An acquaintance also recently came to me asking if I can fix his air conditioner that had a piece of plastic broken off. I do refrigeration work, and he thought I might have a source for buying replacement parts. Unfortunately I had to tell him that companies were not really in the business of selling these little bits of plastic that break on their machines. Aside from having spare motors, relays, contactors, or compressors, they'll just sell the entire unit at a much higher price.
Well, next time something like this breaks, and it's a matter of 'when' not 'if' something breaks, I'll be ready.