Uh-oh...
Are asking about a sprue "paste" or "putty", where you take little bits and melt them with solvent? If so, then I'm not helping you much, since we're talking about two different things.... Sorry about that...
I don't make a "mix"... I lay sprue "rods" down into the openings that need filling, then add the glue.... After that, I just sand to shape..