You can indeed heat Acraglas or other epoxies to thin them. This is especially helpful in cold weather, but heating also accelerates the curing time. Not usually a problem in cool weather, but a fast epoxy might actually kick over faster than you can get it where you want it. Hotter is faster and too hot will actually degrade the epoxy. If I need longer working time, I will thin with lacquer thinner or denatured alcohol, sometimes warming a mixture thinned a bit with either solvent. I have always wondered how much thinning with solvent degrades performance after final cure.
