I had my first experience with exotherm a few weeks ago. I had mixed up too much epoxy for making my leash loop, and left the extra liquid in the cup. I looked over a few minutes later and saw some some smoke coming out of the cup. I could feel the heat just by putting my hands near the cup. Luckily my garbage can was full, and I just poured it out over the top to spread it out. It kept smoking for a while, and I got scared that my trash would catch on fire. Luckily that didn’t happen.
I've been kicking around a similar idea only using the foam shavings that I collect from shaping.
I thought that if I could get it to work it would be a good way to recycle foam packaging as well (feed it through my joiner planer and collect the shavings in my shop vac)
Epoxy would not be a good substrate due to weight and exotherm.
I've tried some others with no success including: gorilla glue (sample had poor consistancy), ehlmers glue (sample dried like granular sand rather than a solid), Spray foam (small sample looked extremely promising but larger sample failed to cure all the way through resulting in a gooey mess when attempting to shape).
Others I've considered but haven't tried yet: Thinned spackle, flour and water (probably a bad idea), 5200 (too expensive?), styrofoam glue (haven't been able to locate any locally but also probably too expensive).
The challenge is to find something that is cheap, light weight, will cure with little or no air flow, remains at least somewhat flexible, can be mixed or purchased in sufficient quantity (and consistency) to be mixed thoroughly with foam beads/shavings and can be acquired with less fuss/expense than a production blank.
I went to an EPS factory and (as I understand it ) the foam balls can be reheated and they will expand even more. Thats why cheap foam has larger cells.
So I guess it would be possible to make a blank shaped metal box and feed all sorts of EPS offcuts in and 'reblow' a blank with steam.
The downside would be uneven density. possible incomplete expansion or cohesion between ingredients.
Maybe for 100K it would be possible to do it, but in the end its all about affordability.... Is it worth the time and R&D to make something thats not too expensive at present ?
My EPS offcuts get mashed into the compost tumbler and make for a light and fluffy garden topping.