Sculpting domino roach burrows?

[Betta132]

I want to try to make a 'burrow' system out of something hard, maybe clay, that I can put up against the glass of a domino roach enclosure. My hope is that I can provide small, dark spaces, accessible by burrowing, that the nymphs will come into where I can look at them. Maybe with a cloth covering over it most of the time. I'd have it solid on top and on parts of the sides, so that the roaches could come up from underneath or in from the open parts of the sides. 

Any ideas what I could use as materials? I need something that won't dissolve if water gets on it, can have coco fiber embedded into it to make it match the environment, and is easy to sculpt. Some sort of dense foam, covered in grout? Maybe a clay I can harden easily in an oven so it won't dissolve if the substrate around it gets a bit damp? 

Alternately, is there a wood that I could carve into the right shape? Maybe a piece of mopani that I can cut tunnels into and try to make it look like a rotting log? 

Is this even worth trying? Any clue if they'd go into it? 

[stanislas]

Interesting approach. Although I think the nymphs will prefer to burrow in substrate such way that their body is in contact with the material. So no hiding in empty spaces, no matter how small. But then again, I don't know for sure. 
It would be a good thing to try this! Let us know if it works! If so, using red light and a camera could enable to watch the nymphs 24/7

Material? Perhaps hardwood is a good option. Or cork bark? Clay ass well if you have the equipment to bake it the proper way.
I would not use resins mixed with materials, unless you are absolute sure that there aren't trialing chemicals in the construction. 

[Redmont]

I would suggest using excavator clay its for reptiles that make burrows. This isn't the best idea for dominos they don't make burrows, they just dig in the soil, i Believe glow spots make burrows, this would be a good idea for desert hairys and death fainters   

[nepenthe]

I recommend dental plaster, hydrocal, or ytong.  The first two are liquid so you can make a mold of your burrow and pour around it, or you can carve into it after it cures (be careful, they're very brittle when cured). I think ytong is bought as a solid so your only option is carving into it.  You can also buy premade ytong burrows: http://www.ebay.com/itm/Formicaio-Antnest-Antfarm-Gasbeton-Ytong-/263166520536?hash=item3d45f26cd8:g:qoUAAOSwB-1Yrn73

[Bufo Bill]

I would go for excavator clay as above, but again this set up may not be suitable for Dominoes. I have also built burrows using this system of peep holes and found it to work well for burrowing spiders and scorpions, it's well worth a go. 

All the best  from Bill.