Taking seconds and putting it in time form help?

So I'm trying to take a time in seconds ex: 120 and turn it into 2:00, I keep getting crazy results though.

function splittime(length) --magic rite
    local seconds = tonumber(length) 
    local minutes = 0 
    local hours = 0
    for i = 1, tonumber(length) do
        seconds = i
        if i >= 60 then
            seconds = seconds - 60
            minutes = minutes + 1
        end
    end
    print("Hours: "..hours,"Minutes: "..minutes,"Seconds: "..seconds)
end

OUTPUT: Hours: 0 Minutes: 205 Seconds: 204 --Not sure how long it is but it's definitely NOT 205 minutes