The Fact About Boiling Polymer Clay Not Myth

To start the test I used Fimo Soft And Fimo Classic, the baking temperature for the clay is 110º C (230º F) compare to Sculpey or other clay. The clay was chosen as it the curing  temperature is closer to the boiling temperature of 100º C (212º F). All polymer clay needs to be condition (ref to the image below)

On the right is Fimo Soft and on the left is Fimo Classic,
the recommended baking temperature is 110ºC (230º F)
for 30 minutes in the oven

Best way of conditioning is by rolling and folding the clay,
 the clay conditioned can stretch thinly like above.

Basic test starts from creating bead, cone shaped cross for
clay adhesion and the 1.0 mm thin strip for flexibility.

It is the same for Fimo Classic which is a better quality clay
  difficult to condition as all Fimo clays are crumby.

Preheat the water in a stainless steel pot or bowl.

Put in all the clay tests to the boiling pot and boiling it for
30 minutes.

Boiling The Clay

Removed the tests and let it cool for 15 minutes.

Observing the Fimo Soft clay after boiling shows blistering
on the surfaces of the clay strip, bead not so on Fimo Classic.

The Adhesion Test

Testing flexibility of the Fimo Soft Clay by bending the
clay strip.

It breaks easily into two pieces.

Bending the Fimo Classic Clay for flexibility test

The Fimo Classic breaks into 2 pieces.

The Hardness Test

The conclusion about boiling the polymer clay in water, will not fully cured the polymer clay, it causes blistering in Fimo Soft clay which the quality is lesser than the Fimo Classic. Although there is no blistering on the Classic clay, it does not make the clay stronger or flexible by boiling. Testing hardness of the clay by dropping the beads on the table at a height of 2.0 feet shows the beads are hard but not fully cured.