Does anyone know the difference between the two: pastillage and gumpaste?

I have seen the same work done with them. Pastillage is used more in latin american countries and gumpaste here in the US.

any thoughts?

Pastillage is made more for structures. You must work quickly with Pastillage.

With gumpaste you can work a little slower and the gums that you use to make it..or gelatine makes it more pliable and flexible so it will take the silicone impressions better.

There are more technical differences, I'm sure someone will post them.

The Pastillage has a shorter drying time. Gumpaste can and will absorb more ambient moisture, therefor more chance at droopiness.

Pastillage is better if you live in a humid climate because it is more resistant to moisture. Basically gumpaste is an American invention and pastillage has been around for centuries in England and the United Kingdom where it is used widely over there. You can make your own pastillage if you want. I have a recipe posted for it in the recipe section forum. Pastillage also from what I have read airbrushes extremely well.

you have to 'seal' pastilage before you paint it...with a little bitty water on your finger..quickly go back and forth and it seals the pores on the sugar piece.

I learned a great recipe from ROCCO from Las Vegas and don't know where I placed it...he uses the little coffee creamer cups to measure one of his ingredients..lol