UV Resin for making key cap

[ju6ju8Oo]

I see a lot of key caps made of resin (acrylic? polyurethane? epoxy? or polyester?), but not many of them is made of UV resin.

What're the pros and cons of using  UV resin verse other resin  for making key caps?

[SquareTomato]

Perhaps, it is not cost effective to produce.

[AuthenticDanger]

There's an ample supply of proven urethane resin for cheap, which is why people use it.

What is the advantage of using a UV resin over a urethane resin (as most people use)?

[Vulcan]

you mean keycaps from 3d SLA printer that use UV resin?

[sinusoid]

The obvious con is that you need UV source for the resin to cure. If you're curing under pressure, the additional con is that you need an UV source capable of withstanding that pressure. Duh.

The less obvious con is that setting depends in UV light penetration into the resin which tends to stop the light itself. So UV resins are best used in thin coats. Most kinds of molds will stop the light from penetrating into the resin as well.

The difference between UV resin and regular resin is that the component responsible for curing is trapped in a chemical compound that releases it when treated with proper wavelength UV light (This component is also the reason why they are so expensive).
Because of this, you can have some interesting properties, like long pouring times, with fast setting on demand (hello touch screen smartphone glues), or being able to set the resin selectively, and wash away the rest of it (hello screen printing, pcb etching, 3d printing)

So, unless you have something specific in mind, this looks a lot like a solution in search of a problem.


Btw, don't ever use polyester resin if you can avoid it. It's leaking xylene throughout its whole lifetime, which is toxic and unnecessary. It also ruins silicone molds pretty reliably.

[ju6ju8Oo]

The obvious con is that you need UV source for the resin to cure. If you're curing under pressure, the additional con is that you need an UV source capable of withstanding that pressure. Duh.

The less obvious con is that setting depends in UV light penetration into the resin which tends to stop the light itself. So UV resins are best used in thin coats. Most kinds of molds will stop the light from penetrating into the resin as well.

The difference between UV resin and regular resin is that the component responsible for curing is trapped in a chemical compound that releases it when treated with proper wavelength UV light (This component is also the reason why they are so expensive).
Because of this, you can have some interesting properties, like long pouring times, with fast setting on demand (hello touch screen smartphone glues), or being able to set the resin selectively, and wash away the rest of it (hello screen printing, pcb etching, 3d printing)

So, unless you have something specific in mind, this looks a lot like a solution in search of a problem.


Btw, don't ever use polyester resin if you can avoid it. It's leaking xylene throughout its whole lifetime, which is toxic and unnecessary. It also ruins silicone molds pretty reliably.

So, should I start with hard epoxy resin? is it the most common in the artisan keycap community?

[ju6ju8Oo]

you mean keycaps from 3d SLA printer that use UV resin?

I plan to pour UV resin into a silicone mold, and let it cure.
But it seems that other resin is more commonly used. So I want to make sure I'm not doing something stupid before I start.

[Vulcan]

Hmmm.. if you are using that method.. i think its better use epoxy resin

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[sinusoid]

I plan to pour UV resin into a silicone mold, and let it cure.
But it seems that other resin is more commonly used. So I want to make sure I'm not doing something stupid before I start.

UV resin needs an ultraviolet light source to cure.

You can pour it in the mold allright, but it won't be setting anytime soon.

Also - "UV resin" describes the setting method, not the chemistry. You can have UV polyurethanes or UV epoxies (and probably several others).

edit:

Yes, start with epoxy. It has long setting times, and is not very toxic once cured.
Read through threads, read through molding forums, see what people use, see what you can buy easily in your location.

[ju6ju8Oo]

There's an ample supply of proven urethane resin for cheap, which is why people use it.

What is the advantage of using a UV resin over a urethane resin (as most people use)?

Is urethane resin a type of polyurethane that I should avoid for home use?

The UV resin I found in Japan is a 1-part material that doesn't require mixing. Some of them are premixed with colors.
Another advantage is, it can be cured in 10min. So, layered color seems to be easier.

But, it seems that transparent epoxy resin is clearer comparing to UV resin. And UV resin is around 2-3 times more expensive.

[ju6ju8Oo]

I plan to pour UV resin into a silicone mold, and let it cure.
But it seems that other resin is more commonly used. So I want to make sure I'm not doing something stupid before I start.

UV resin needs an ultraviolet light source to cure.

You can pour it in the mold allright, but it won't be setting anytime soon.

Also - "UV resin" describes the setting method, not the chemistry. You can have UV polyurethanes or UV epoxies (and probably several others).

edit:

Yes, start with epoxy. It has long setting times, and is not very toxic once cured.
Read through threads, read through molding forums, see what people use, see what you can buy easily in your location.

Yeah I guess it's UV-curable epoxy resin in my area.

[sinusoid]

You should be able to find other types of resins in Japan. In the past I saw people in the modelling/kitbash scene use resins bought locally to cast customs or make low volume runs of their models. You're essentially looking for the same stuff. Ask around what people use, try auction sites, modelling supply shops, ask on local sites/forums, look for distributors of materials for special effects. See if Smooth-on has a distributor, or if you can find anything by Axson or Huntsman. You should probably have local manufacturers as well.

Assume that no resin is safe for home use. Most of them contain toxic volatiles. Use in a well ventilated area, mix well, don't let your skin contact uncured resin or its components, and make sure you do not overdose any of the components when preparing the mix.

[ju6ju8Oo]

You should be able to find other types of resins in Japan. In the past I saw people in the modelling/kitbash scene use resins bought locally to cast customs or make low volume runs of their models. You're essentially looking for the same stuff. Ask around what people use, try auction sites, modelling supply shops, ask on local sites/forums, look for distributors of materials for special effects. See if Smooth-on has a distributor, or if you can find anything by Axson or Huntsman. You should probably have local manufacturers as well.

Assume that no resin is safe for home use. Most of them contain toxic volatiles. Use in a well ventilated area, mix well, don't let your skin contact uncured resin or its components, and make sure you do not overdose any of the components when preparing the mix.

thank you sinusoid. Great tips!