Attaching shells into a printer's tray
Though I've posted before to the Remodeling Forum, I'm new to Crafts, so hope I'm asking this question in the right place :-)
I would like to display a collection of seashells by placing them in a wooden printer's tray, then hanging the tray on the wall.
What is the best way to secure the shells? Since there will be no glass cover over the tray, I really do not want them to come loose and fall out. I'm thinking some kind of adhesive, but not sure which; there are so many types! Would a simple glue gun work? I don't want the glue to be too obvious so as to distract from the seashells.
The link shows a picture of what I want to make.
Thanks in advance for any advice you can give.
Here is a link that might be useful: Printer's Tray with seashells