Better way to cut visor carefully?

So i'm thinking of buying/building a vacuum form table to make helmet visors. To do that i assume i need to cut the visor out perfectly.... Problem is that i am not so good at cutting out visors so well as i usually cut right down the middle or if i try to cut it precisely i still end up missing the corners or have to cut a little in the middle of the visor to cut the curve edges. Sooo my question is what are better technique to cutting a visor good enough to look good when it get vacuumed formed?

I'm still new to props, all i have right now to cut is a dremal with some basic cutting blades.

Thank you in advance for your help.

Simple: don't cut the visor out. Assemble a new one, make sure it's supported and rigid, and then vacuum-form that instead. Assuming you're not making your visor a half-inch thick, the plastic you'll likely be using to vacuum-form a visor form from will be flexible enough to offset any slight intolerances between the visor port and the finished piece.

You could even export the model to a 3D modelling program and create a model just for this purpose - if you'd like, I could take a half-hour at some point to do this for you.

You will still have to work on the visor if you want to use it for vacuum forming - or either it'll break apart under the pressure.
So, you can cut it just on the sides after hardened, and then still work on it, add missing details, etc.
Or like Chernobyl said - make a new one.

You also have to take into account that you can not just cut the visor out of pep'd and fiberglassed helmet and then immediately vacuum form over it. Because the vac former is pulling down over the piece, you need to fill in/block off the sides of your mold/buck. Otherwise the plastic gets pulled over and then under what you are trying to vacuum form over becuase of the under cut. This picture is an example of an ODST visor mold/buck that shows what I mean:


The mold/buck extends all the way down to the table on all sides. That is the only way to ensure a proper pull that will also allow you to remove the plastic from the mold with no worries.

I guess i will try to cut it out slowly and be as precise as i can possibly be then fill in the imperfect cuts.The helmet is 3D printed from dutch props. So i could use that cut out visor, but i would have to reinforce the bottom like making the visor into a block almost?

delta6020 said:

I guess i will try to cut it out slowly and be as precise as i can possibly be then fill in the imperfect cuts.The helmet is 3D printed from dutch props. So i could use that cut out visor, but i would have to reinforce the bottom like making the visor into a block almost?

Click to expand...

You can work on the surface of the visor however you want.
You just have to make sure you'll fill the underside of it fully with foam or something that will withstand the pressure. Depends on how many times you want to use it.