Produced, engineered and mixed by Jay Ruston (Anthrax, Steel Panther), Grandpa Metal features guest appearances from some of metal’s finest including Brendon Small (Metalocalypse, Dethklok), Scott Ian and Jonathan Donais (Anthrax), Corey Taylor (Slipknot), Gary Holt (Slayer, Exodus), Jeff Pilson (Dokken), Alex Skolnick and Chuck Billy (Testament), Al Yankovic, Pearl Aday, Johan Hegg (Amon Amarth), Joe Trohman and Patrick Stump (Fall Out Boy), The Damned Things, Michael Starr (Steel Panther), Jacob Bunton (Mars Electric), Rob and Aiden Cavestany (Death Angel), Steve “Zetro” Souza (Exodus), Kim Thayil (Soundgarden), Phil Demmel (Machine Head), Ron “Bumblefoot” Thal (Guns N’ Roses, Asia), and the late Jill Janus (Huntress).