Charlie et al,
Sometimes reinventing something can be a good thing, especially if it goes awry and something profound comes out of it. Most times though it's just ignorance of the fact that it's already been done before. I seem to be an expert in the latter category...,
After a little thought I remembered something I posted a long time ago on this website several predecessor versions ago.
For a great texture paste try mixing Grahams Rock Hard Water Putty with white glue and a little water to thin it to the right consistency for your application. This can be anything from a clay like mud to a thin coating. Use a textured roller to get a stippled effect; a sponge for an uneven stippled effect. Adding graded sand can yield interesting textures especially after letting it setup a little and then washing the surface with a wet sponge. I've made some great looking columns for a model of the Temple at Karnak with this method. Didn't even have to wash with a base color as the water putty was perfect as is.
Anohter great combination is to use old water based house paint as a mastic base. Especially if it's white and it's partially dried up. That's the best as most people will want to throw it away. You can use water putty, plaster and other base thickeners to do the same as above. It makes a pretty good adhesive for paper mache and if it's the right color you won't have much finishing work when your done. Scorpio has already started down this path with his mixing acrylic paint with PVA glue.
In fact that's really what's involved here. Your looking for fairly low cost adhesives that are compatible with paper. Adding things like plaster and water putty adjust the viscosity and working qualities for the application at hand.
How to apply the paste as a rivet is now in the hands of Charlie who has gallantly been nominated and auto-inducted into that post. We'll all be expecting a full report on the progress you've been making within less than a week or so...., We're depending on you now...,
There...., that should be enough to keep you off the streets at night. Instead you'll be doing strange, unusual but constructive things late into the night....,
Remember to tell the unbelieving, "Did I tell you that's it made from paper?"....,
Best regards to all, Gil
P.S. Nice light box Leif. Think I'll make another one along those lines...,