I recently put this together for my Step-Son. The assumptions, getting a trade, (I used plumber)and 25% tax.

Career Path Hourly Start Weekly Weekly Post Tax
Plumber Helper $8.50 $340.00 $255.00
Apprentice $10.50 $420.00 $315.00
Journeyman $14.50 $580.00 $435.00
Certified ? ? ?
Pay scale chart $8.50 $340.00 $255.00
$9.50 $380.00 $285.00
$10.50 $420.00 $315.00
$11.50 $460.00 $345.00
$11.75 $470.00 $352.50
$12.00 $480.00 $360.00
$12.25 $490.00 $367.50
$12.50 $500.00 $375.00
$12.75 $510.00 $382.50
$13.00 $520.00 $390.00
$13.25 $530.00 $397.50
$13.50 $540.00 $405.00
$13.75 $550.00 $412.50
$13.95 $558.00 $418.50
$14.00 $560.00 $420.00
$14.25 $570.00 $427.50
$14.50 $580.00 $435.00
$14.75 $590.00 $442.50
$15.00 $600.00 $450.00
$15.25 $610.08 $457.56
$15.50 $620.00 $465.00
$15.75 $630.00 $472.50
$16.00 $640.00 $480.00
$16.25 $650.00 $487.50
$16.50 $660.00 $495.00
$16.75 $670.00 $502.50
$17.00 $680.00 $510.00
$17.25 $690.00 $517.50
$17.50 $700.00 $525.00
$17.75 $710.00 $532.50
$18.00 $720.00 $540.00
$19.00 $760.00 $570.00
$20.00 $800.00 $600.00