Fixing spacebar mechanism on Falcon keyboard
Posted: 10 Jan 2026 22:22
I had to do some work on a Falcon keyboard and while disassembling it, found that the plastic catch holding the spacebar carriage had cracked. When I lifted the spacebar to look, it fell off.
Of course, when I tried to detach the metal bar from the other side, the second catch also broke off :P ...that escalated quickly. It was supposed to be an electronic repair.
Now I had to figure out a good way to glue these back and decided to try welding them with acetone. Depending on the plastic, this can work better than glue (or sometimes it makes things worse).
This worked really well. Here's exactly how I did it.
- Practiced putting the piece back accurately with tweezers a few times to make sure it sits correctly and there will be no gaps or obstructions when it is back in position. In this case they both broke with a pyramid-shaped shear which made this bit easy.
- Insert the metal bar FIRST so it doesn't have to be pushed in after the broken parts are restored to their positions. It's easier to position the bar then fix the catches on top of it.
- Dip the sheared end in a cap of acetone a few times, then 'dab' it into the seat where it should be welded so acetone is wetting both faces of the weld and gets a chance to dissolve material on both faces.
- Dip it one more time in acetone then place it exactly into the seat and press it gently down to let it weld. Hold it there until the acetone gets sticky, which is a few seconds.
- if it's not perfectly straight, carefully straighten it with the tweezers but always pressing down a bit.
- Leave it well alone for a couple of hours.
Here's the first catch welded.
...and the second.
I removed the white plastic loop from the left end of the spacebar so the metal bar can be pushed into the remaining one which is still attached. This seemed to be the least awkward way to reattach the plastic keytop since the metal bar is already fitted under the plastic catches.
...then put the loose loop over the left end of the metal bar and pushed it into the spacebar, so the bar is now mounted.
Fixed!
...and then back to the original repair, which was rebuilding some corroded tracks that had disabled some of the keys. That's now also fixed and the machine is working again.
Of course, when I tried to detach the metal bar from the other side, the second catch also broke off :P ...that escalated quickly. It was supposed to be an electronic repair.
Now I had to figure out a good way to glue these back and decided to try welding them with acetone. Depending on the plastic, this can work better than glue (or sometimes it makes things worse).
This worked really well. Here's exactly how I did it.
- Practiced putting the piece back accurately with tweezers a few times to make sure it sits correctly and there will be no gaps or obstructions when it is back in position. In this case they both broke with a pyramid-shaped shear which made this bit easy.
- Insert the metal bar FIRST so it doesn't have to be pushed in after the broken parts are restored to their positions. It's easier to position the bar then fix the catches on top of it.
- Dip the sheared end in a cap of acetone a few times, then 'dab' it into the seat where it should be welded so acetone is wetting both faces of the weld and gets a chance to dissolve material on both faces.
- Dip it one more time in acetone then place it exactly into the seat and press it gently down to let it weld. Hold it there until the acetone gets sticky, which is a few seconds.
- if it's not perfectly straight, carefully straighten it with the tweezers but always pressing down a bit.
- Leave it well alone for a couple of hours.
Here's the first catch welded.
...and the second.
I removed the white plastic loop from the left end of the spacebar so the metal bar can be pushed into the remaining one which is still attached. This seemed to be the least awkward way to reattach the plastic keytop since the metal bar is already fitted under the plastic catches.
...then put the loose loop over the left end of the metal bar and pushed it into the spacebar, so the bar is now mounted.
Fixed!
...and then back to the original repair, which was rebuilding some corroded tracks that had disabled some of the keys. That's now also fixed and the machine is working again.