Trying To Duplicate A Canopy In Vacform

[Supertom]

OK fellas, I really need your help here.  I have a clear canopy that I'd like to modify.  Unfortunately I can't risk destroying the original and I'm having hard time getting my hands on a spare.  I'm thinking that I could make a mold out of the canopy, reshape it the way I want then cast my vacform out of that.  Does anyone have any idea on how I could do this?  I was thinking of packing the inside of the canopy with some self-hardening putty like Milliput, then taking it out and using that as the mold.  However I suspect the putty will stick inside the canopy.  Is there anything you might suggest to use as a release agent?  I was thinking cooking spray or baby powder.  

So, any ideas?    

[Scooterman]

Perhaps covering the inside with Bare metal foil or plastic wrap?  After your mold hardens, the foil or wrap should let it pop out without harming the master.

[HOG]

I find a quick wipe round the inside with vaseline or similar with a q tip/ cotton bud releases milliput when set. Add a piece of sprue into the milliput when soft as a handle/leverage.
Remember though that the inside of a model part can be a totally different shape to the outer due to casting thickness etc.
If possible pack the original with bluetac and a small rod and put in fridge to set. Make a small frame to hold some clear sheet. Fix your original into a table vice and smear with the vaseline. Heat the clear sheet with a hairdryer or better yet a hot air paintstripper and when floopy push over the original.
This may give you a useable copy slightly bigger than the original or a basis to fill and sand as required to remould.
Hope this helps
Gary  

[Orne M]

Coat outside/inside of canopy with vaseline, pack it with modeling clay so it can be handled without cracking, then press the canopy parts into warm modeling clay to make impression.  Multiple impressions can be made.  Clean the vaseline off and store the original or use it.  Plaster or resin can be poured into the impression(s) to make masters.

[Brian da Basher]

Wow vacuform? That's waaay to elegant and complicated a solution for me. I'd take the canopy, make a mold out of modelling clay and then cover the outside of the mold with foil and simply smash-form copies.

Let us know how this comes out!

Brian da Basher