He was the youngest of the five children of hoop-maker John Saunders, and started a career in paper-making while in his twenties, becoming partner in a paper mill in 1840.
At the Irish exhibition of 1853 there was special mention for his "specimens of paper ornamented with a water mark, showing gradations of light and shade".
and the watermarks attracted many banks as customers, and made T. H. Saunders & Co important suppliers of postage stamps and banknotes to many countries in Europe, the British Empire and South America.
The technology for this had been invented by William Henry Smith,[2] and the design was created by "thin brass plates upon the bottom of the mould".
As a supporter of the Shaftesbury Society which promoted ragged schools, he set up reading and writing classes for children from his mills.