Attach an entity to a prop and make it keep an angle?

So I am trying to make some sort of C4 that will attach to props. But I can’t get it to place “flush” with the prop. Like I want the bomb to be locked in an angle so even if the prop is not straight it will place like this:

Now when I tried to make this by using the props angle and hit position, like bomb:SetAngles(prop:GetAngles()) but can’t get it to work. So if someone could help me on the path to getting this right I would really appreciate it. I don’t want you to send me code but to explain how I would do this.

Set the C4’s parent to the prop.

Entity:SetParent

Use the hit normal instead of the parent prop’s angles.

[lua]
bomb:SetAngles(tr.Normal:Angle())
[/lua]

You might need to do some additional rotations to that angle, but that should at least get you started.

Thanks, that helped a lot. At least got it semi-working ^^.