No not at all, that's why I like using CA so much. You just can't let it sit around. Never do more filling than you can file flush and sand within about a half hour otherwise it gets harder than the surrounding plastic and becomes hard to work. I use a medium thickness CA and accelerator. Wait about 5 seconds after you hit it with the accelerator, wipe it off with a tissue and start right in with the needle file. The faster you start, the softer the CA is, and the easier it is to take off with the file.