Can I cut and replace a section of a silicone mould?

[johnojodo]

Hi Everyone
As the title says I'm wondering if I can cut a section off a mould and remould that section?

I've spent some time on a 3d printed helmet then moulded it, It wasn't till I did my first pull I realised the file was very wrong so I started to cut and shut with fiberglass and bondo adding a load of weight to the front of the helmet.
So I'm thinking if I cut the problem sections off (Jowl and under ear sections) Put the remaining section back onto my moded pull and re mould the exposed section. Will this work or is my cheap A** flogging a dead horse?

Thanks for any help
Ed

 

[PoopaPapaPalps]

I've always had iffy results doing this. Unless the mold will tightly hug against the positive, you could get away with cutting and replacing sections of it if you're careful, but in my experience, there is a greater chance of this leaving another seam.

 

[ChickenHaunt]

You can definitely try it, but expect to have to do clean up work on the castings, because it's not going to be a perfect join.

 

[propninja]

You would be better off making a new mold. if you try to reseat your part into the mold and don't get a perfect seal, the new rubber will leak in. I've tried it more than once and it never works right. What you can do is to cut or grind up the old mold and use it as filler. It will be worth the added expense to make a new mold, and you'll get better results.

 

[johnojodo]

Thanks for the replies guys, big help ... new mould it is