OpenForge/OpenLock bases chamfered for 3D pen welding

A few months ago I bought a 3D pen on a whim. It was in a bin. They were practically giving them away. And it used the same 1.75 mm filament as my printer at home, which meant I had an abundant amount of filament, you know, scraps from the Bowden tube and whatnot. It was good fun for about two hours, but sort of crude and useless when you own a 3D printer, so it was put in a drawer and forgotten. Then I started printing out OpenForge pieces for DnD, and needed a way to join the walls/tiles with the bases. To save on cyanoacrylate, I thought I’d try welding them together with my rather useless 3D pen. It kind of worked, but the joints were weak, because the PLA had nowhere to go. I needed to build up enough PLA with the pen to get a heat build up that was sufficient to fuse the new PLA with the PLA in the parts. The flush joints didn’t allow this, so I experimented with chamfering the top edges of the bases with a knife. And now the welding joints seemed to hold together. Whittling away with a knife is all good fun, but it gets tedious after a while, so I decided to chamfer DevonJones’ base pieces in Sketchup once and for all. A few tips if you want to try 3D pen welding:

Reduce the 3D pen flow to fairly low. You want to add material and heat over a little time. The pen’s tip is hot, and will preheat the surfaces you want to weld. This is crucial to make the PLA fuse properly. Or as close to properly as this technique gets. It’s by no means perfect.

My pen have two modes of operation. A short click on the extrude button starts automatic extrusion. It feeds filament by itself until I press the button again. If I press and hold the button down, it only extrudes as long as I hold the button. I prefer to use the latter when I weld.

My pen retracts the filament quite substancially every time I let go of the feed button. When I weld, I keep the tip at an angle into the joint, making good contact with the two surfaces I want to join, and facing me, so I can see when it starts to extrude, and how much PLA I’m filling into the weld.

When it starts extruding filament, I let the filament build up a blob in the gap between the pieces before I start moving the tip slowly along the joint, making sure that I fill the available space along the chamfered edge. I keep the tip in contact with the pieces I’m welding the whole time, to keep them heated. This seems to do the job. I’ve had some joints come apart, so my technique isn’t perfect, but it works more often than not, it seems. Time will show how well this stuff keeps together.

There will probably be some messy welds that may need some work afterwards. I just cut them flush with a knife. A Dremel would probably do the job faster or neater or both, but mine’s in the garage. It’s two flights of stairs down, so I can’t be arsed.

If you have any experience in welding with a 3D pen and suggestions as to how it can be done better, please let me know in the comment section. I only have a couple of days of experience with this.