Does anyone know of a thermoset resin that is viscous like melted glass before it sets? I want to create objects that are glass-like. Bulbous glass objects are that way because of liquid glass’s viscosity and gravity/etc acting on them as they cool/harden. Is there a thermoset plastic that has similar properties?
Or what if you cooled the plastic as it cured? Would this give it more viscosity? Or would this just rob it of the heat that it needs to cure?
C’mon modelmakers, throw in two cents.
epoxies-look at the post above regarding epoxy/polyester mixes.
Thanks Acala. I am the Guest (the more wordy one) from the recent thread you joined on patents. Do you mean epoxies are very viscous before setting or that they can be made more viscous prior to setting by cooling?
Epoxies are thermosets that crosslink in an exothermic manner (They get hot when the hardener/resin is mixed).
Two-part room cure epoxies have a “pot life”- working time that occurs from the time of mixing until “gelation”. When first mixed, most epoxies viscosities go down. At the point where gelation begins (when the epoxy goes form liquid to solid), viscosity goes up-fast. This can be controlled somewhat depending on a number of factors-catalyzation rate, mix temperature, volumetric size of the mix and so forth.
A fast kick epoxy with a short pot life (400g with 5-10 minute pot life) can give you a material that at about 3-4 minutes after mixing, you can achieve your “melted glass” viscosity (~500,000cps). But you will only have a couple of minutes to work it before it kicks over all the way.
Pouring in 400g+ pots create a whole set of other issues. It’s predictable, but with a lot of trial and error.
If you need epoxy formulator resources, let me know.
Thanks much! 3-4 minutes is more than enough time - way more. Do you know if using a heated mold/form helps it to kick over faster?
400g+… cavities? sink? craze?
BTW, is epoxy foodsafe?
Heat will DEFINITELY increase the rate of catalyzation. A general rule of thumb in room temperature cure epoxies is that for every increase in temperature of 10 degrees C, you half the viscosity and double the catalyzation rate.
Fast catalyzation is not necessarily a good thing, though. With fast catalyzation comes shrink, internal stresses, high exotherms, poor surface finish, etc.
Foodsafe- formulation can be made to be foodsafe. Eopxies are inherently inert