How Would I Go About Scaling an Entity?

[Henchman128]

Hey, I'm wondering if anyone is able to help me with a lua issue I'm having.
I have an entity created, with physics.
I want it so that when it is created, it starts at a size of 1 then scales to a size 3 times as big over the course of 3 seconds.
(Everything below is under my ENT:Initialize() function.)
[lua]self:SetModelScale( self:GetModelScale() * 3, 3 )[/lua]
Unfortunately, this doesn't do anything, and I'm told that the issue is that my entity has physics, so I tried sleeping it.
[lua]local phys = self:GetPhysicsObject()
if( IsValid( phys ) ) then
phys:Sleep()
self:SetModelScale( self:GetModelScale() * 3, 3 )
end[/lua]
Again, no result. The weird thing is, if I set the duration of the scale to be 0, the entity scales properly. The takeaway from this is that the entity only scales on the first frame it is created, I can't seem to figure out how to have it scaled over a specified duration.
Any and all help is appreciated.

[Henchman128]

Bump.
Maybe there is another entity that someone could share with me as reference which performs this task?

[whitestar]

math.approach should do the trick for 3 seconds?