Sharon;
What kind of equipment you invest in for dyeing depends on what kind of dyeing you plan to do after the class. For my shibori I dye large batches of silk scarves, 600g -3000g at a time in large stainless steel kettles or my small dye machine. Rignt now we are dyeing samples and I like to dye more than one at a time. I use a constant temp. bath because that is what I have that can reproduce the machine cycle.
This is a water bath with a heater controlled by a theromstat. Here is the control panel, sorry about the fuzzy pic. It has a on/off switch and a dial for the temp. This bath can hold up to 8 beakers for sample dyeing.
There is a time lag between when the bath reaches a temp. and the dyebath inside the beakers reach the same temp. I previously used a canning pot and mason jars on a burner- this requires more babysitting but is cheaper and readily available. Tien uses an electric skillet with a temp. controller from honey processors, and others used steam baths or other electric cooking devices. Some of these are pictured in the document attached to the class description which I am attaching here again. You will need a thermometer to place inside the jars to measure the actual temp. of the dyebath.
This is something we can share and learn from each other.