Hi
Im new at this, having made one uni-mould and one putty-mould before this.

i have a beaten plastic underside panel on my car that i was hoping to create a mould from.
As i have not been able to source a mint piece, this is what i have to work with.

Underside (facing away from the mould)





Side facing the mould



So i was thinking of taping and gluing it back together.
To cover the holes, where the plastic is gone i figured i could use some sort of backingplate, and fill it up with plasticine.

Any advice appreciated

Thanks guys.
I decided to start with another piece from the underside that is not broken, it got some damage, but its easily sorted.


Since the part has several large gaps i tried using expanding foam, has anyone tried this?


As you can see i have started cutting the foam and the plan is to use the uni-mould system.
I have ordered lots of stuff from EC, Flash tape included.
And i recon i can cover the "swiss cheese" with this tape and then cover the whole part with tooling gel.
The problem is that the EC package hasnt arrived yet, so the question is, is there anything else i can cover with?
I got

The reason i tried expanding foam is that i found it to be to much hassle with cutting polypropyleneboards to fit everywhere.
I got #8 mould release, and lots of plasticine, maybe a thin layer of plasticine to cover up the foam holes?
As you can see the part is in a bit of a rough condition, so i am prepared to sand and polish the mould once its done.

Any suggestions appreciated!