The pressure you spray at is dependent on how thin the medium is and what you are trying to achieve. You can spray model paints at anything from 10-40 psi if you want, although anything over about 25-30 is probably overkill.
The lower the psi the better control you have of overspray, but the paint must be thin enough to flow at such low pressure.
Mike
“Wisdom is the right use of knowledge. To know is not
to be wise. Many men know a great deal, and are all the greater fools
for it. There is no fool so great a fool as a knowing fool. But to know
how to use knowledge is to have wisdom. " Charles Spurgeon