For the Mama's Who Know About Hodge Podge...

I love Mod Podge and have used it for years. (Check out my groovy switchplates!)

No, not stinky. And while it's easy to use, there are some things to consider (which I've learned the hard way, so maybe this will save you a bit of heartache)
~~Let your layers dry before adding another on. You want "deliberate wrinkly", which will look fine, not 'saturated wrinkly', which will look like grandma's old newspapers left out in the rain and dried-- deep, heavier wrinkles where the layers are trying to dry and heaving a bit.

~~If your canvas has a color, use a fixative/sealer first. Applying MP directly onto some colors will moisten them again and the color will smear everywhere.

~~If you need something to be flat on the surface you are applying it to, carefully apply MP on the back of that piece, then use a brayer to smooth it. (a brayer is a sort of roller with a handle, meant to keep things flat and even)Then apply the top coat if you choose.

Don't forget that MP comes in Glossy and Matte. I use the glossy for more handled-items (like switchplates) and matte for things like candles. Also, don't forget to seal your work with a clear spray varnish, or it can be damaged.

More info than you might have needed-- have fun! (Also great fun for your kids while YOU work-- give them glass jars and tissue paper-- have them decorate the outside, then stick a tea light in. Voila!)

You have a number of different options:

- Shellac

- Gesso comes in several different finish types (transparent matte, transparent semigloss, transparent gloss, and opaque).

- Fixative

- Mod Podge

In school... we usually used Gesso or Shelac for the kinds of things you're talking about.

All hodge podge is is Elmer's glue with water... Equal parts. And yes, it works like you are describing though I haven't done it on canvas. Great idea!

I think you mean "Mod Podge" but I've never used it to be able to answer your questions. I'm interested to learn though.

I've used Mod Podge for years now. I am highly sensitive to fumes...& yes, it bothers me as a permanent marker does. School glue is pretty much the only product which doesn't trigger my allergies. :)

Mod Podge is great....& has worked on every single one of my projects. This past Christmas, my daycare kids made wooden ornaments. We used Mod Podge to cover the ornaments with scrapbook paper, & the moms loved the gifts!

When I was a kid in elementary school, we'd make collages on many kinds of objects. And all we used, was slightly watered down Elmer's glue.
And it lasts.

Canvas... if it is not stretched first, will then stretch (taut) when put onto a frame. Then, the collage you applied onto the canvas, may not "stretch"... because the glue is already dried on it (or shellac or whatever you used).
So, the collage, may crack sort of.
Imagine, putting clear fingernail polish on a cotton knit. Then let it dry. Then stretching it out on a frame. That clear finish will not stretch. After it is dried. Or the canvas, will pucker, in all the wrong places.

Anything glue like or shellac like, can be used as an "adhesive" clear coating, for making collages.
But some things, if applied too thickly, will "yellow" when dried. But some people want, that effect.