Endurecer esferovite (isopor)

Ora aí está uma combinação que permite fazer de tudo um pouco: 

-Trabalham fácilmente, com ferramentas baratas, Lâminas de corte, Cola própria, e Lixa;

-E depois de acabarem, aplicam-lhe Verniz de Madeira, ou um Líquido próprio, e lavável, e zás! 

Têem um Material resistente, para as vossas Engenhocas!

Neste Site de Miniaturas, falam do simples Verniz de Poliuretano para Madeira, para endurecer a Esferovite, parece que penetra nos interstícios da Esferovite, e aumenta a rigidez das peças:

A while back someone posted a foam hardening method while discussing making terrain boards using the normal expanded styrofoam. They stated that after they shaped the foam, they painted a polyeurethane type wood varnish onto the foam which soaked into the spaces between the foam "balls" and hardened creating a honeycomb of varnish. The foam was as hard as a rock afterwards. You might be able to use the varnish, then apply any texture you need on top and shape as needed.

http://theminiaturespage.com/boards/msg.mv?id=164060

Mas também há esta intrigante gama de produtos específicos para endurecer:

#026 - Exterior Foam Coat (3 lbs)

Brand New! Rock hard finish for all of your outdoor (and indoor) foam projects. This stuff is super tough. It is not sandable. Has a rough stone feel when dry. It can be troweled smooth, or brushed to make a super rough finish.

-Adheres to polystyrene foams.
-Forms a weather resistant surface.
-Easy to mix. Just add water.
-Covers Up to 300 square feet.
-Use above or below grade
-Apply with paintbrush or trowel.
-Paintable
-Fireproof
-Many decorative surface textures can be created.
-Soap and water clean-up.
-Try adding Boost fortifier. (will not work with Bounce)

  
http://hotwirefoamfactory.com/-026-Exterior-Foam-Coat.html 

Vejam os dois Links acima com vagar, são uma fonte desta e de muitas mais dicas...

Aqui está um vídeo ilustrando a aplicação destes produtos na Esferovite:

...E como se tudo isto não fosse o suficiente para vos pôr a cabeça à roda com múltiplas ideias, aqui vai a ùltima dica, a Ponoko agora corta...
Styrene!
Por enquanto só em 0,5 mm de espessura, atenção, podem agora fazer milhares de coisas com a precisão do Laser!

Styrene – May Material of the Month

The white knight of model making

Styrene, or as sometimes it likes to be formally addressed – High Impact Polystyrene Sheet (HIPS) is one of the most ubiquitous plastics around, even though it’s too humble for most of us to pay any notice to.  Like PETG, it’s commonly used in food packaging, where it’s thermoformed for specific applications. When it comes to laser cutting, fabricating components for model making is where this material truly shines.  Prefab laser cut model kits are already available for the likes of railways, trucks, aeroplanes and buildings.  Styrene’s properties make it an excellent material choice for these applications.  While it doesn’t cut as precisely as acrylic, it is easily sanded or scored with a craft knife, which is perfect for leaving sprues (little “bridges” of material) to hold parts in place.  Partially laser cut parts can be easily snapped off the kit sheet and sanded back for a clean edge.

http://blog.ponoko.com/2012/05/01/styrene-%e2%80%93-may-material-of-the-month/