It is crucial to get a thin glue line when making TEM cross section samples, so normally a clamp is used to press the samples together during curing. Several types of clamps are available commercially, however almost all of them have a big disadvantage: the pressure cannot be adjusted. Basically there are two types of clamps. Type 1 is a small vise that uses a screw to press the samples together. There are two problems associated with type 1. The first one is that usually the viscosity of the glue decreases during the initial stage of curing, so even if you had tightened the screw hard, the sample could still get loose because the glue becomes thinner as its viscosity reduces. To get a thin glue line with this type of clamp, one has to keep retightening trje screw when the clamp and sample is being heated.