Can someone tell me what is the difference between CMC, Tylose, and vegetable gum and gum arabic?

CMC and Tylose are the same thing. I think Tylose might be a brand name. They are a chemical compound used to thicken gumpaste and other things in cake decorating (I'm sure you already knew that last part!). I don't know about vegetable gum. It might be the same thing as gum arabic, which is a plant-based substance that is used for about the same things CMC/Tylose is. It's the more traditional ingredient (my mom used it in things when I was a kid, but I only came across CMC when I got into cake decorating seriously a couple of years ago), but it's about twice as expensive as CMC and not nearly as easy to find nowadays, although I'm sure it's fairly easy to obtain online (what CAN'T you get online?). Some recipes state that you must use gum arabic (or gum tragacanth, which MIGHT be the same thing, but I'm not sure!) rather than CMC, but mosty they're interchangeable. HTH !

The gums traditionally used to make gumpaste are all vegetable gums. Tylose is a brand name of CMC powder. The technical term is carboxymethyl cellulose and it a chemically altered plant cellulose. Gum arabic comes from the sap of an acacia tree. Gum tragacanth comes from the sap of a few different plants.

They all do the same thing in slightly different ways. I prefer CMC (tylose) as it dries faster and the resulting gumpaste is a true white where gumpaste made with gum arabic or gum tragacanth has a dull hue to it and it takes much longer to set up.

Thank you, thank you, thank you, lilmissbakesalot! I love this site, because you learn something new every day!

No problem at all. I remember when I was just getting into caking and it was all greek to me.