A 12 oz tiki torch should last between five and six hours. Sadly, there is no eternal flame for backyard fires. Even solar-powered lights will fade after 10 or 12 hours. Be prepared by stocking up fuel. Don’t try to concoct your own “emergency” fuel with rubbing alcohol or other chemicals. Leave it to the pros. DIY modification of the torch to try and get more life out of the fuel can result in dangerous fires, ruined torches, and horrible, horrible parties