casting molds of plastic/rubber/fiberglass parts? anyone done it?

[Zsolt]

Hey Chris,
Here is a good how to article with photos about reproducing an original 
part in fiberglass.
http://www.hotrod.com/howto/60478/
Cheers,
  Zsolt

JordanVw at aol.com wrote:

>im looking to reproduce a rear wing/spoiler for a vw that is no longer being 
>made (rear spoiler for the vw mk1 cabriolet).  i have found an original  but 
>the owner doesnt want to sell it, tho he has granted permission for me to make 
>a copy.  the spoiler is not mounted, and is a black rubber/foam type spoiler 
>like those used on the A2 jetta or audi 4000q, and looks similar.    i was 
>thinking of reproducing it.. the finished product does not have to be done in 
>rubber/foam, it can be done in plastic or fiberglass, whichever is easier to work 
>with.  what is the best way to make a mold, without damaging the original?  
>and what is the best bedium to cast it in?  fiberglass?   anyone have any 
>experience with this?  
>
>thanks
>
>  
>