I need a low-viscosity liquid that will harden into a white solid

[THX1138 1]

I have a small hobby project in which I'm printing some keyboard keycaps with an SLA 3D printer with the intention of filling in an inset legend with some kind of paint or resin which will harden in a contrasting colour (white since the SLA resin is black) but I don't know exactly what to use. The spaces I fill will be really small so I need to use something with low viscosity which I can inject with a (blunt, narrow needle) syringe and it will self-level and harden very slowly so I have time to inject about 70 characters in total. I know two-part resins are available but I don't know their viscocity or if there are more suitable alternatives. Can anyone advise a suitable material available in small quantities for this purpose?

 

 

[JohnInOttawa 104]

I think your epoxy option might be good.

 

You can get epoxies with the viscosity of water and control the color with additives. In my part of Canada, West System epoxy is available in a wide array of consistencies and hardness,  I was able to find one that was fluid enough and had a long enough setting time that I could allow it to soak into spalted maple and fill the internal cavities before setting.  Color control was easy with this stuff as well, I needed to match surrounding wood grain and was able to use simple dried out, used coffee grounds.  They dissolved beautifully and the result was flat and solid, with enough give to absorb wood movement without inducing stress along the bonds.

 

If you do go the epoxy route, it might be easier to coat the surfaces you don't want epoxy on with a release agent, then you can fill the inlays without worrying about staining.

 

Not sure if that's an option where you are, but hopefully this give you an idea.

Cheers

John

[geert_2 558]

Search on Youtube for mould making and casting. There are a lot of companies promoting their materials with how-to videos. From there you can find their company websites and product specs.

 

In the Netherlands in Amsterdam, there is a big shop for modeling, moulding and casting materials and tools. They have it all: clay, plasticine, plaster, silicones, lots of composites, colors, etc... And they have downloadable catalogs with some explanation. See: https://www.formx.nl/

Maybe this could give some inspiration?

 

[valcrow 145]

2 part, smooth-on type casting urethane will fit the bill. Very liquidy when mixed, like maple syrup (not that fake corn syrup stuff) Hardens in about 10 minutes and turns white after hardening.

[peggyb 171]

don't know if you decided on something yet...

other option is a clear uv resin and some coloring. Nice thing is that it stays liquid until it is exposed by uv light.

There are some uv light around used for fingernails.

[THX1138 1]

Thanks, peggyb. Someone else suggested enamel paint which is available cheaply in very small quantities (for painting models and miniatures) so I will probably end up using that.

[geert_2 558]

4 hours ago, THX1138 said:

Thanks, peggyb. Someone else suggested enamel paint which is available cheaply in very small quantities (for painting models and miniatures) so I will probably end up using that.

Yes, paint might be worth a try. Paint is probably easier to wipe away with a tissue than composites or PU. I used that method as a kid for painting white cement in brick walls, in HO-scale model houses.