OK I am getting ready for my next cake decorating class. It's Wilton course 2, and I have to make gum paste adhesive. Since it's a Wilton class I will be using the Wilton recipe (1 tbsp meringue powder, 1 tbsp water). I am wondering how long it will keep if I place it in an airtight container and keep it at room temperature and how long it will keep in the same container, refrigerated. Any thoughts or suggestions? Thanks! :)

AUse your gumpaste to make the adhesive by breaking small chunks of gumpaste and put in the water. The water will dissolve the gumpaste. You don't have to wait for all the gumpaste to dissolve to start using. It will start to smell after a couple days. The first night of class the instructor should be showing you this part since the first night you work with fondant/gum paste flowers. The rest of course 2 is royal icing flowers.

AWhen I make Gum glue I put 2 tsp of Tylose in a small jar (a clean babyfood jar works well) then pour 1/3 - 1/2 C boiling water in. I then put on the lid and shake vigorously, venting occasionally. I then let it rest with the lid on loosely for at least 5 hours.

I don't think that an egg glue is strong enough for gumpaste. Good Luck!

I agree about using bits of gumpaste.  I keep dried scraps in a small ziplock bag to make glue with when I need it, and make a small fresh batch every time I need some.  Takes only a few minutes to dissolve if the bits are small enough

It's great that you're all trying to help, but none of you have answered the original questions!  I would, but I have no experience of this so can't answer, sorry!
 

AFrom my initial post you know that I don't use a meringue glue but I'd make it fresh each time if I did.

Maybe I'm behind in the times but I have never heard of mixing merengue powder with water to make glue. I doubt it would be strong enough. I, like everyone else that replied, use either gumpaste dissolved in water or tylose mixed with water. Those will last a couple of weeks in a jar in the fridge.

I've heard of making them from gum paste and water and also meringue powder and water. After reading some of these comments I'm leaning more toward using the gum paste.

The suggestion are right on.  Even plain water will glue GP to GP.  Once mixed together (water/MP) it will keep at room tmep about 1 week.  It depends on how warn that room temp is :)  The warmer the less days it will keep