ROTJ Sintra Helmet Build

[Malurus2000]

Greetings, fellow Star Wars enthusiasts!

This would be my formal introduction to the boards, but I'm not quite the stranger. These forums have helped immensely thus far in my ROTJ build.

However, what I am struggling with is my helmet build. I have made the grave error or brave move in making it from sintra board. Thus far I am proud of my work (possibly because the difficulty and patience I have thus far put into it), but right now it's just what I'd call a base. I am wondering if there's any advice you guys could bring to this predicament.



Here's what I have so far, the base of the bucket. As you can tell, there's a bit of tape on the interior and at the brow of the T-visor. This is only a temporary fixture until I can get some proper bonding material. The original brow broke, so I placed on a second one to keep stability and for more completion.



A different perspective on the replacement brow, you can see it's on a different layer. I doubt it will interfere enough where I have to revise it, as the brow and other pieces should be protruding later anyways.





It doesn't show up too well with the res, but on the right cheek here there's a tear. I'm hoping it'll mostly be covered up or that the primer will help cover it if it interferes with the cheek.





The back of the bucket, as you can tell, needs to be cut so as to carry the vents. I plan on doing that LAST so as not to compromise the stability of it as is.



The bucket's round, I'm not sure if it should be or more oval shaped.



Lastly, the two cheek pieces aren't exactly symmetrical, I'm hoping when I take out some of the interior tape it'll fall into place (and maybe hit it up with the heat gun again).



As you can see, I have no dome, earpieces, or cheekbones. For the dome, I was thinking of taking a half-ball foam from Walmart or something of the sort, then shaping it, do something about the texture like filling it up with E-600 glue, adding the dent, and hollowing it out. The dome is my primary concern, I don't want to make a sintra dome and use bondo on it. Any other ideas on a dome that can be worked and have the dent added to it?
For the earpieces I am quite stumped on what I should do.
As per the cheekbones, I do have pieces for it, but I'm not sure they'll work, and might have to remake them into a better shape. I also don't know when or how I should attach them.

Any help would be appreciated, thanks!

 

[Gregory]

I made my dome from a 10" hemisphere from the craft store, cut and reshaped etc.

 

[Grimstuff]

Yeah, I did my whole bucket in Sintra, it can be a pretty hard material to work with sometimes, but it does make for a really nice strong and smooth sculpture. You can check out my thread here if you want, though my initial assembly part is the least documented unfortunately.

What I'm seein from your pics it looks like you might have gotten too ahead of yourself in some places. You pretty much don't want to cut out the T-visor or remove the internal support skeleton until everything is already curved and stably in place, as otherwise it can cause all sorts of problems with the structure and curvature of outer-layers. The outer layers are pretty much just two big rectangles that you curve around into circles, if a big section is missing in em it can make getting an even consistent curve a nightmare.

Something that really helps is to pre-form the pieces too a little via heat-curving. Just bending them straight-up can create a lot of stress on the plastic which is where I suspect might be where those cracks came from. Heating the plastic up and curving it around a large bucket or something puts the plastic into a natural curved shape that's much easier to work with. Careful to keep the heat even through the piece though and not overheat and specific part, as it will make that part more bendy than the rest and can create a inconstant curve there too. Also Sintra is PVC, which releases dangerous gases when heated, so have very good airflow and wear a respirator if you can.

As for bonding agent, I found cyanoacrylate superglue to be the best, it bonds extremely fast and the thin stuff will seep some down into the cracks you're trying to bond. You can pretty much do spot welds with it while curving your forms together, tacking up one section before moving to the rest. Much better than slower curing stuff like plastic cement.

As for the dome and supplement pieces, dunno. You'll pretty much have to hope you can find some ball shaped thing somewhere that's the exact diameter you need. It's going to be a pretty tough build though if you don't want to use any bondo, it's pretty essential for smoothing things up and hiding seams. If you're just worried about the fumes, you could use something like Apoxie Sculpt instead which is non-toxic. It's more expensive and difficult to sand though.

 

[Malurus2000]

Yeah, I did my whole bucket in Sintra, it can be a pretty hard material to work with sometimes, but it does make for a really nice strong and smooth sculpture. You can check out my thread here if you want, though my initial assembly part is the least documented unfortunately.

What I'm seein from your pics it looks like you might have gotten too ahead of yourself in some places. You pretty much don't want to cut out the T-visor or remove the internal support skeleton until everything is already curved and stably in place, as otherwise it can cause all sorts of problems with the structure and curvature of outer-layers. The outer layers are pretty much just two big rectangles that you curve around into circles, if a big section is missing in em it can make getting an even consistent curve a nightmare.

Something that really helps is to pre-form the pieces too a little via heat-curving. Just bending them straight-up can create a lot of stress on the plastic which is where I suspect might be where those cracks came from. Heating the plastic up and curving it around a large bucket or something puts the plastic into a natural curved shape that's much easier to work with. Careful to keep the heat even through the piece though and not overheat and specific part, as it will make that part more bendy than the rest and can create a inconstant curve there too. Also Sintra is PVC, which releases dangerous gases when heated, so have very good airflow and wear a respirator if you can.

As for bonding agent, I found cyanoacrylate superglue to be the best, it bonds extremely fast and the thin stuff will seep some down into the cracks you're trying to bond. You can pretty much do spot welds with it while curving your forms together, tacking up one section before moving to the rest. Much better than slower curing stuff like plastic cement.

As for the dome and supplement pieces, dunno. You'll pretty much have to hope you can find some ball shaped thing somewhere that's the exact diameter you need. It's going to be a pretty tough build though if you don't want to use any bondo, it's pretty essential for smoothing things up and hiding seams. If you're just worried about the fumes, you could use something like Apoxie Sculpt instead which is non-toxic. It's more expensive and difficult to sand though.

Thanks for the info, this is pretty helpful.

As per the last point, I didn't mean to insinuate I was not willing to use bondo, I meant having to take a bunch of sintra triangles, bending them into the dome, and then using bondo. Sorry, I can see why that was confusing. I just don't quite know if the dent is done in the bondo exclusively or it