Flashpoint Question

I am making a mixture of the following:
50% Isopar L (flashpoint = 142F)
50% 3-Methoxy-3-methylbutanol (flashpoint= 154F)

These 2 solvents appear soluble in each other at this ratio.

The flashpoint of the mixture is consistently lower than either of the
solvents alone (typically around 136F).

Is there an explanation for this or am I having a problem with my flashpoint
machine (closed cup).

Thanks for any help.

Jeff


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