Fixing warped PBT space bars

Has anyone seen a good video or clear instructions on how to make a warped PBT space bar straight? I’ve seen lots of anecdotal information with hot water, heat guns, even hair driers but nothing definitive or scientific.

I’ve had limited success fixing them and wonder if it’s actually possible to make them perfectly straight, especially with PBT’s high tolerance for heat.

Would love to find a tried-and-true method if it’s out there!

Well I used the hairdryer method 2 times and worked great.

  1. Hold the spacebar in your hand and heat up using the hairdryer moving it up and down across the length without insisting on one spot or being too close.

  2. Feel how warms it gets and try to see if it’s a little flexible by trying to bend it slightly.

3.Place it on the countertop in the kitchen, put one of these on top https://www.tthamisa.ro/wp-content/uploads/2018/09/tocator32.jpg
And some weights on it.

4.Wait until it cools down, check result & repeat if needed.

P.S: English is not my native language and I can’t find how that wood thing you cut things on it in the kitchen is called…a chopper?

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cutting board

Good guide. I will caution you not to try to bend it too aggressively. I snapped one in half once trying to see if it was bendy yet :slight_smile:

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Thanks for the instructions. I’ll give it a try.

I’ve pretty effectively straightened my spacebars by boiling water, popping my spacebar in, letting it soak then squishing it under a heavy book. The key is making sure that the water is super hot BEFORE you put the bar in, because then you get some not-very-pleasant plastic smell. I tend to boil on high and then soak on low, to minimize icky plastic smell.

I tried that method but couldn’t get it to work for me.

Your mileage may vary. It was very effective for my DSA and Cherry spacebars, and not quite as much for my MT3 bars. What profile are you straightening?

Cherry. How long did you let it boil in the water?

So, what I did for my cherry bar, if I remember correctly, is that I got some water boiling, and then poured it into another container with the spacebar in it, and let it soak for around 5 minutes before squishing it under a book. This was with the PBT Muted set, where the keycaps are stupid thin, so it might be different for a thicker cap.

I would not recommend that since you can actually start to dissolve pbt in water at boiling point. Snapped stems get more likely.

Good to know. I’m going to give the hair dryer method a try and report back.

I use this heat gun on the lowest setting. Heat up the space bar (mostly in the middle), put something heavy on top for a few minutes until it cools. Repeat if necessary. I’ve had to do this with all of my DSA sets from PMK and it’s worked out well.

So I’ve done some experimenting and have an update that I think works well:

First I heated a spacebar with a heat gun on the “medium” setting for about 30 seconds. After becoming quite hot I placed a flat cutting board on top of the spacebar with some additional weight and set it on my flat kitchen counter until it cooled down. This method reduced the bend but didn’t get rid of it completely, even after multiple attempts.

Next I used the same heat gun method, but this time, I gripped each end of the spacebar with a couple of towels (because it was super hot), and I over corrected it so it essentially was bending the opposite direction. I then used the cutting board/kitchen counter method to flatten it and let it sit there until cool. This made it absolutely straight—as perfect as any GMK spacebar I own.

Since refining this method, I’ve corrected 3 PBT spacebars with the excellent results!

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Well done ! Love the DIY correction stuff.

Next, adding centered stems to 6u spacebars :smile:

No center stem? No problem :slight_smile: https://imgur.com/a/xGc3oAZ

  1. Get Epoxy glue
  2. Sacrifice a stem from a keycap by cutting it with a nail clipper/whatever. (I used some grab bag DCS keys)
  3. Place a dab of epoxy and place the stem inside. Wait for it to harden a bit but still be maleable.
  4. Place the keycap/spacebar on the switch + stabs while the epoxy is not completely hardened and make sure the key sits proper/goes down ok and let it cool/harden.

Tip: practice makes perfect, if it doesn’t go well in the first try, just push on the stem and peel together with the epoxy, clean the stem and repeat.

This also works if you wanna make OG stepped caps lock to be centered stem, but it’s more difficult, and you have to use a shorter stem, and also work an encline for the keycap to sit at the same angle/height with the rest of the row.

Cheers!