Veneers and surface checking question

[KingwoodFan1989]

On my current project, I'm complementing the Brazilian Cherry (main wood) with some Pomelle Maple veneer I got from Veneer Supplies. Looks great, although it's a massive pain to flatten. One of the pieces of veneer had been flattened between paper towels and some particleboard shelving for about 24 hours and then was clamped between two other pieces of shelving for a couple days or so. The other piece, I flattened and then about 36 hours later, I decided to bookmatch and edge tape the veneers. I noticed the veneer, at least the more recently flattened piece, still felt a little bit "cold". I got a pretty good edge and taped them together, and then I glued them and some backer veneer (plain Maple) to a piece of Baltic Birch. Although the backer had some spots that got a little bit "scrunched" off the surface (by like a 32nd or so---didn't use cauls for the backside on that glue-up---big mistake), in general everything adhered great and I only had to re-glue the corners and one odd spot on the edge. 

However, I the veneer being cold was of concern to me. I e-mailed Joe (the owner of the supplier) and he said usually that means it's not dry yet and that if glue holds it in place while it dries, it can lead to checking. I did notice that after 24 hours of being glued to the panel, the seam between the two veneers started to develop a tiny hairline crack between them, which has showed up in a couple other places along the seam after I brought the panel indoors to dry (hopefully) quicker. The veneer feels dry to the touch now and I don't see any checking. However, I'm still somewhat concerned. I'm gonna wait a little bit longer after flattening before gluing the other panels, and if it does start to check, I have extra veneer. However, I LOVE how this glue-up turned out on the main face, and I'd feel like it'd be a waste to have to toss it. How long should I wait before cutting the necessary rabbets and installing the panel in its place on my project? Once it's there, I can't remove it if it starts to check. Is there some set time period within which it will start to check, or is it probably good now if it feels dry but hasn't checked? I can use a little bit of wood filler or sawdust to get rid of the hairline gaps that have shown up in the center joint line, but I need some insight into how checking works.

Thanks!

[KingwoodFan1989]

Hate to double post, but does anybody have answers to my questions here? I'd like to know more about this.

[FS7]

Hate to double post, but does anybody have answers to my questions here? I'd like to know more about this.

For starters, I'd recommend a moisture meter to make sure you're working with materials of similar moisture content. That's also the way to check whether your veneer is actually dry or just feels that way. In my experience most wood feels dry unless it's completely soaked with preservative (like wet PT lumber), but "feeling dry" can cover a pretty wide range of moisture content.

Essentially you are waiting for the veneer to reach its equilibrium moisture content. It will continue to check until it reaches that. If you are looking for a way to cover that, consider a small inlay along the seam with a contrasting wood. 1/4" square dowels work well for this purpose. If installing the panel prevents you from doing this, then wait. 

The simple answer is to get and use a moisture meter to monitor the MC of your veneer. If it's changing, it's still moving, so let it go and don't fix anything until it's reached equilibrium. In the future, don't work with it until it's reached equilibrium (and this goes for everything, not just veneer).