45 G Boba U4
Ok, I have finally tried it with 45 G springs. An interesting experience for me.
I have never used springs this light. And I knew that there would be issues, given how borderline the 55 G unlubed U4s were.
I am inexperienced with lubing, but I used the included brush to lube the slide rails on the stem, and the internal rail cutouts in the housing, with the included #6 blend. I very carefully lubed each end of the 45 G spring with the brush.
While assembling, I could see that the stem did not want to leave the housing bottom, at least not at first. As I eased the top housing onto the bottom, the stem elevated itself, and I was able to mate the housings. I experienced more difficulty doing this than with the other spring weights.
The first few times I pushed the stem down, it hung a bit, just staying there. But as the lube spread more evenly, the stem popped up consistently.
In the board, with GMK keycaps, there was some hanging at first. But then the switches functioned regularly.
It’s a strange feel. It reminded me of those light but tactile rubber domes you might pick up from any store back in the 90s or early 2000s. The beige rubber domes.
The closest comparison is to the 55 gr (unlubed) U4. The unlubed U4 was also barely functioning at first, but then got into its groove. In terms of tactility, the 55 G has what I experience as a richer, broader tactility. It almost feels like a 45G Niz dome on the ABKO K935P. Not as rich or soft or as long a stroke as the ABKO, but the tactile intensity and weight of the 55gr U4 seems to be within the same ballpark.
With the 45 G U4, you can really feel that contour, the shape of the tactile legs as it plays out. You can feel it more in the 55 gr than the 62 gr, and moreso still in the 45 gr. I find that there is less ‘noise’ and general tactile ‘richness’ in the lubed 45 compared to the unlubed 55 gr, and the 45 gr is mostly about the shape of the tactile legs. Which is very pronounced. It’s not sharp, there isn’t enough weight or speed, it’s more rounded.
I think if you are going the 45 G route, you are going to want to lube very carefully. I don’t know how it will perform with heavier modifier keys, I haven’t tried it. It seems to work on the alpha keys, but it can be very sluggish on the upstroke. That’s why I say you will need careful lubing.
I got away with not lubing the 55 G on the alphas, but I doubt that is ideal. I think the next step for me is to try lubed 55 G. Because I am liking the 55 G U4, it is my favourite 55 G yet. [The only 55 G I like.]
It is also worth noting that the keycaps on the 45 and 55 G Bobas seem to be a little lower than their nearby brethren, which are HPs and T1s and other tactiles.