Best way to replace/fix broken Alps caps?

[keycap]

So I have some Alps doubleshot keycaps that have a snapped stem. Only a few of the caps are broke, but they are alpha keys so they are important. Don't ask how I managed to break them, it was a long time ago and I used one of those plastic keypullers. One of the sides came loose while I was pulling, putting all of the force on one side of the keycap... and you can guess what happened from there.

I still have the broken stems. I just need a way to fix/replace them. Would superglue work? Or do I have to find another set of caps from somewhere?

[Chyros]

So I have some Alps doubleshot keycaps that have a snapped stem. Only a few of the caps are broke, but they are alpha keys so they are important. Don't ask how I managed to break them, it was a long time ago and I used one of those plastic keypullers. One of the sides came loose while I was pulling, putting all of the force on one side of the keycap... and you can guess what happened from there.

I still have the broken stems. I just need a way to fix/replace them. Would superglue work? Or do I have to find another set of caps from somewhere?

You can either replace the caps or superglue them to the slider. When you do, obviously, you condemn yourself to not being able to open the switch again, though.

[fohat]

You can either replace the caps or superglue them to the slider.
When you do, obviously, you condemn yourself to not being able to open the switch again, though.

Superglue is an impermanent fix in my experience. I use a good epoxy when I an serious about a repair, but the fact that it can drift during the drying period is a problem.

But I agree, just glue them back together until you can replace them properly.

PS - I feel for you - I have 2 keyboards with uncommon caps with 1 broken - probably no replacement to be found, ever.

[E3E]

I always use Plastaid for anything that's acrylic based like ABS. It will permanently bond with the plastic as long as you're patient and let the joint completely dry.

I've even used it to fashion an Alps stem for a PBT Cherry space bar I swapped for use on an Alps board. It doesn't bond chemically to PBT, but it still creates a good mechanical bond. What I did for the stem swaps from Cherry to Alps is to fill the cruciform mounts with this stuff, let it dry, then dremel'd the stem down.

It's nice that Alps uses such simple mounts. Getting a little off-topic here, though.

This stuff should work well for creating strong bonds with ABS caps though. http://www.amazon.com/Plast-aid-80400-P ... B004DFHSM6

Chryos, you've got to know a good solvent or glue for PBT, right?

* I've also done plastic welding with ABS to repair gouges in cases and such, and it works really well if you're careful.

I know you can plastic weld with PBT, but I've not had any success with it in my experiments with PBT key caps. Gotta be careful with the smoke and fumes though. Nasty stuff.

[Chyros]

Chryos, you've got to know a good solvent or glue for PBT, right?

PBT is much harder to glue than ABS, because PBT resists most types of glue quite well, including and especially superglue and epoxy glues. Acrylic glue is good but not excellent.

As far as "chemically welding" PBT like you can ABS with acetone; this is not as easy with PBT. PBT is much more resistant to most solvents. It's weak against acids and NaOH, but that would probably result in degradation rather than dissolution. However, it appears that they might dissolve well in chlorinated hydrocarbons. I stock quite a few solvents in my house but unfortunately none of those, but I can take some DCM/EDC/CHCl3 home to test maybe. EA is supposed to dissolve it slightly but I just tried and it does fuck all basically.

[keycap]

Wait, so I could join the stem back on with acetone? These are ABS caps that I'm talking about.

[fohat]

Perhaps in theory, but I suspect that the acetone would evaporate much faster than you could work with it.

[E3E]

Thanks for the notes, Chyros. Definitely helpful, and I certainly felt like PBT didn't have many options. Hope you find something in your experiments.

By plastic welding, I meant by using a soldering iron, haha. I've done that to fix things like a broken lug on one of my Docutechs. One came with a broken lug for its unique feet, and first I tried gluing it with super glue, failed. Then I tried using the plast-aid stuff. It worked for a while but wasn't so strong.

Then I just took some similarly colored ABS and used it to weld the snapped piece back on and it's good as new. Had to sand and shape it back down but yeah, it's very reliable now.

It's not the perfect way to go about things and the plastic fumes are definitely not friendly, but sometimes it's the best option.

[Chyros]

Perhaps in theory, but I suspect that the acetone would evaporate much faster than you could work with it.

No, acetone isn't THAT volatile . This treatment is more useful for bigger pieces of ABS though, not something as tiny as a keycap stem xD .

[derzemel]

I had the same issue with 2 Cherry Dyesub PBT keycaps and the best glue I could think of was a 2 part epoxy (it's called Poxipol here in Romania).
It has worked like a charm and I have tried the keycaps on multiple cherry mx switches (except clear as I do not have those).
This is how it looks on the numpad Enter:

Spoiler:

The only thing I had to be careful is that I had to let it cure about a day after I glued the stem, to be sure it has completely hardened.

I do not know how well it would work with ALPS steps as those are smaller than a MX stem and a greater force is required to pull them from the switch.
If the keycap stems are the hollow type, I think you can fill the stems with the epoxy as it will harden and it will offer more support.

[Chyros]

So I tried DCM, and the short version is no, it doesn't work - at all. It doesn't even touch it xD .