Wing Mika Mika and hooker and Colin Hokianga each scored twice, and stand-out players included stand-off Hayzley Robson, contributing a try and landing seven of his eight goal attempts, teenaged fullback Tyson Johnson, who also scored a try, and second-rower Boy Waaka.
In the other game, Phoenix, down 16-12 after having first use of the wind in their game, threatened to go into the lead with a converted try just after the break, and again when they bounced back from Outkast's reply to lead 24-22.
But that was effectively the end and Outkast found the gates wide-open in a last-quarter attack which suggested a real threat to Tamatea, given they were without Peniasi Tokakece, who is expected to be available for the final after returning from a short rugby Sevens trip to Sri Lanka.
Kevin Oli scored three tries for Outkast, and a trio of Fomai whanau contributed a combined 34 points - Ausage with a try and nine goals, Neria with two tries, and Tafita with one.
Outkast's second team missed out on a Reserve grade final when beaten 30-26 by Hastings, who in league's big day at Bill Mathewson Park next Saturday will meet Omahu Huia, 56-26 semifinal winners over Bridge Pa.
In the women's grade, Seals beat Omahu Huia 20-4 on Saturday to secure a match-up with Tamatea women.