GMK Spacebar straightening

The idea is to heat the plastic enough to be able to mold it, but not to let it melt. This can be done with water or a hairdryer, but that is difficult to control, hence this experiment with a hot print bed in a 3D printer.

TL;DR:

Requirements:

• 3D printer with a temperature controllable bed
• Heavy objects to put on the spacebar

Steps:

• Put spacebar on printbed, place heavy objects on sides of spacebar (hard disks, fat books)
• Heat printbed to 85c celcius
• Keep printbed at this temperature for 5 minutes
• Cool down printbed gradually to room temperature (~21 degrees for me)
• Boast to friends that you have a flat GMK spacebar

Wait- what, bending spacebars?

Yes! All the GMK spacebars I have up to date have had some slight, or significant, amount of bending straight of the factory as you can see in the below picture. This is annoying because it can cause your spacebar stabilizers to tick because once you’ve assembled your keyboard.

So I’d like to bend them back. Bending ABS plastic while it’s cold is a recipe for disaster (you’ll break it, or it will deform and show discoloration due to the stress you put on it). So let’s heat it up!

The work

I had a few options on my table:

• Use a heatgun -> I’d rather not melt my spacebar
• Use a hairdryer -> Ok, less risk of melting, but also no uniform heat distribution
• Hot water -> Actually great option if you can control the heat of the water, and can find a way to slowly cool down the keycap while under the ‘straightening’ pressure.
• Printbed of a 3D printer -> Temperature control? Check. Is it fully uniform? Only on the bottom (where the spacebar touches the bed). Still, does give the option for gradual reduction of temperature whilst retaining pressure on top of the spacebar. Let’s try this out.

Cooling down

Pulling a hot spacebar off the plate and letting it quickly cool down sounded like a bad idea. A mix of cold and hot plastic (top and bottom) tends to warp even more if you don’t try to control the environment (ask anyone who 3D prints with ABS, if the ‘room’ isn’t a high temperature you get deformations quite quickly). I’m not suggesting to warm the room, but cooling down gradually whilst remaining the top-down pressure on the spacebar sounded like a safe way to ‘form’ the keycap into it’s new permanent shape.