Assigning C1 to a weld not doing anything in my script?

So I have a script, and I'm trying to make a cool lightning body effect. I managed to get what I was looking for, but the meshes kind of dragged back when I moved, so I decided to try welding it and changing the C1 instead of just changing the meshes' CFrames.

My goal was to have the lightning meshes placed randomly around each part of the player's body all the while being welded to the parts, but changing the C1 of the welds doesn't seem to do anything. I do know the C1 is changing though, thanks to a print test, it's just not changing the position of the meshes.

Without Welds: https://gyazo.com/dcd1ce6203874895d51866620f16ff91

With Welds: https://gyazo.com/48944708dcb93c180b64d81ceb4d6394

Script:

-- Varaibles
local part = script.Parent

for i,v in pairs(part:GetChildren()) do
    if v.ClassName == "MeshPart" then

        local weld = Instance.new("Weld",v)
        weld.Name = v.Name
        weld.Part0 = part
        weld.Part1 = v

    end
end

-- Lightning Effect
while wait() do

    local spread = (part.Size.X + part.Size.Y + part.Size.Z)/3

    for i,v in pairs(part:GetChildren()) do
        if v.ClassName == "MeshPart" then

            local weld = v:FindFirstChild(v.Name)
            v.Transparency = 1

            if weld then
                weld.C1 = CFrame.new(math.random(-spread,spread),math.random(-spread,spread),math.random(-spread,spread)) * CFrame.fromEulerAnglesXYZ(math.random(0-(math.pi*2),(math.pi*2)),math.random(0-(math.pi*2),(math.pi*2)),math.random(0-(math.pi*2),(math.pi*2)))
            end
            wait()

            v.Transparency = 0

        end
    end
end