Making visor mold for vacuumforming, when helmet part is ready?

[Teacherinspace]

What would be best way to proceed with this:

My astronaut helmet base looks like this (opening has to be trimmed at least 1,5cm wider):


I would need to make mold for this kind of buble visor: (Image ESA/Alisse)
Visor is not perfectly rounded.

I think I have to craft this visor from foam or similar over this helmet and take mold of whole thing. Then use this mold for casting real visor mold from plaster or something similar. Or is it possible to use hardened foam visor directly as a mold for vacuum forming? What you think?

Any tips or ideas are very wellcome!

 

[8 perf]

What kind of shape can you get by blowing up an ordinary balloon inside? If it will work, cover it with plaster for a negative mold, then cast in more plaster for the inverse, sufficient use of release agent between layers of course, that should give you a decent buck to vac form off of.

 

[Teacherinspace]

This might actually work:confused

Any other options?

 

[Teacherinspace]

Balloon does not work. Even larger ones wont fill hole completely since it is very tall and partly rectangle. I probably have to spray urethane foam over the opening and carve visor from it.

 

[Teacherinspace]

I have (luckily and for great relief since huge frustration and disappointment was near) found a new company that can do main visor (clear buble visor part) pull for me. This company is in another country and shippings will be expensive. I have only 4 weeks left so everything has to go right in first time.

I will appreciate all ideas, help and answers you can provide.


Visor material will be Vivak (PETG) 2mm thigh. Mold cant be higher than 8".

I live in middle of nowhere in Norther Europe and I cant get all supplies easily. I have plaster, polyurethane foam, blue dense insulation foam boards, and polyester body filler (PP100). If I need something else, I have to order it online.
Visor shape is rougly drawn here. It is not part of a sphere. It is more like buble towards front.

What do you think: Is it possible to make good mold from these supplies or should I get something better.
How would you proceed? I probably have to do this next weekend...

 

[sandy11]

you can glue the insulation foam together to the thickness that your visor should be then cut and sand it to the shape that you want then seal the foam with white glue before add fiber glass resin then vaccum form the visor when you get the mother mold smooth enough.