Advice for molding/casting 3d printed FO Stormtrooper armor

[Jonnyboy0121]

Hi all,

I've been working on a suit of custom sized 3d printable First Order Stormtrooper armor. I derived the model from ripped game model file posted here on the RPF.
I've been doing a lot of work on the geometry to get it smooth and printable, and also breaking it apart to fit in my 3d printer's build volume. Here is the original post:

http://www.therpf.com/showthread.php?t=242693





What do you think of the fit?



The 3d printing, bondoing and sanding of the printed pieces is pretty straight forward for me. I have a couple of questions about specifically molding the 3d printed armor.

I printed the pieces fairly thin (1/4 inch) to save material and for it to print quicker - but should I have made it thicker so I could slush cast it thicker?



I'm thinking maybe if I just modeled in a return edge or lip all along the armor edges I would still save on material but have more of a lip for my mold. So something like this:



So to sum it up, if I want the armor to be a certain thickness when cast, do I need to make sure my printed armor is that thick as well?

Has anyone tried casting the back yoke in one piece? From what I understand, the Anovos suits separates into two parts with an adjoining strip of plastic. Then you bondo and sand down the seam. I heard this causes a lot of cracks. I was wondering if I could kind of slush cast the back piece in one go, sort of overlapping the plastic as it's curing. Something like below, where each different color represents a new batch of plastic I work in and then let mostly dry before moving onto the next section.




And finally, I have seen other prop makers use 3d prints for vacuu-forming. How do you derive a forming buck from a 3d print? I've considered vacuuforming pieces but I assume any ABS printed parts would deform in a vaccuform table as well.

I appreciate any advice!

 

[bookface]

You could just add a lip to your print using apoxie sculpt or something similar. Your idea for slush casting the back yoke would also work fine, some people do do larger casts in stages, though I would suggest just using gelcoat/fibreglass.

 

[Jonnyboy0121]

Thanks for the tip, bookface. I just looked up gelcoat/fiberglassing the pieces as I was unfamiliar with the technique.

Is there any significant disadvantages or advantages to making it out of gelcoat/fiberglass as compared to slush casted resin?

 

[bookface]

Well there's a couple of different materials to fibreglass with, polyester or epoxy. Polyester is cheaper, but it smells very strongly and will shrink slightly when curing. You can avoid any real issues with this by not leaving the gelcoat for too long before laying the mat or cloth on it. Epoxy is more expensive and will murder your moulds, especially if there's any undercuts, but has virtually no shrinkage and not much odour. You will either need fibreglass mat specifically for epoxy resin, or the woven cloth. You should still use a respirator with either though.

As compared with slush cast resin, it will be lighter, stronger and probably cheaper to make, but with a fairly steep learning curve.

 

[Jonnyboy0121]

Okay, cool. I actually did a bit of research on it as well. I've worked with bondo fiberglass and resin before and the technique doesn't look all that dissimilar after the gelcoat. And I actually like how easy the gelcoat looks. My main concern is toxicity of the finished pieces. Are they safe, say if I make a helmet using those materials and I'm breathing and sweating in it? I could imagine using something like Rondo to seal it but I wonder if there's a common approach otherwise.

 

[bookface]

Gelcoat is simply a thickened fibreglass resin, it's no different to using bondo/rondo. This is how I make all my helmets, once it's cured, it's cured.