Follow

I tried some casting! These keycaps haven't turned out perfect - the corners didn't have enough resin, not sure why. But once they're fully cured in a week they'll be cool to try out!

The moulds I've made have turned out really well but I have a long way to go with the casting. I think it would help to change to an epoxy with a mix ratio closer to 1:1, so there's not a really tiny amount of hardener to measure out.

The keycaps should be fully cured now! They feel a little tacky when you put them against a hard surface - not sure if that's just what polyester is like.

The bottom corners weren't quite filled but the caps feel nice! Weirdly they had the texture from the original when I demoulded at 2 days, but lost it during the rest of the cure.

The long cure time and the lingering styrene smell are making me want to switch to epoxy/urethane before I do any more casting.

Oops, turns out my polyester resin keycaps don't like being removed with a keycap puller! The resin is too brittle :(

Anyway, I already wanted to use epoxy or polyurethane. Hopefully they'll be a bit tougher.

@gbrnt how accurate was it in regards to any kinda wobbling on the stem / too snug fit?

@mintey It seemed pretty much the same as the original keys, maybe a tiny bit looser but not wobbly

@gbrnt Lingering styrene smell and tackyness = not fully cured yet.

If you don't _need_ them to be clear, mixing some fibres (glass is typical, but many other kinds can be used) will make them much stronger and not shatter like that.

Epoxy is also much stronger and less tricky to mix correctly.

@yngmar The styrene smell from the parts is gone, but not from the cupboard where I store the resin!

I think I just can't measure the catalyst accurately enough in these tiny quantities, even with a small syringe.

@gbrnt Easier if mixing a bigger batch. Or try one of these, that's what I've just got for the same problem and it's great:

#scale

@yngmar I've got a scale that's slightly smaller with similar precision - I could see that my individual drops of catalyst were about 0.05g, which sounds right. I'm really not sure why that wasn't accurate enough. I also mixed for a good amount of time and scraped the sides well.

Either way I'm looking forward to using some epoxy with a 2:1 ratio or something

@gbrnt so you made the moulds yourself?
Do you have more pictures of casting the moulds?
I can see some Lego marks 😁

@LittleJoeMuc Nothing super detailed unfortunately - here's what I have.

I made the first half of each mould by sticking a keycap base-down on a 3x3 flat section of lego, surrounded by a row of studs before the wall. Cast that half and then flipped it over.

The second half had some 3d printer filament on the key corners to create sprues in the mould. First half was coated in vaseline to prevent sticking, which worked well.

The moulds turned out really nice! I just need to work on the resin.

Sign in to participate in the conversation
Mastodon for Tech Folks

This Mastodon instance is for people interested in technology. Discussions aren't limited to technology, because tech folks shouldn't be limited to technology either!