Total Newb - Looking for advice on building helmet

Hello Everyone,

So I have been bitten by this bug to build some armor. So, I started doing some looking around online, and began creating an idea in my head about how I might go about the Helmet (I always like to start with the hardest part first...). I am a CAD guy and so I went to my strength and started to design a dome for the helmet. I modeled up a dome, and created a framework, that I think could be used as a type of mold. Not going as far as vacuum forming, but I was thinking I could use a heat gun and hand mold the plastic around it. I'll try to attach a picture of my mold idea.



Basically, I was going to use some 1/8" plywood to make a grid pattern (Like dividers in a box) that was cut to match the inside of the dome. I have it all modeled, and I don't think it will be too tough to put together. I guess what I really wanted to know, is what type of material should I use. I obviously want to use plastic, but I don't know for sure what type of plastic to use. Has anyone done anything like this? What was your experience and what type of material did you use? I have looked at Sintra, but I'm not sure if that would be the best material to use. Something that when heated becomes pliable and would form well over a form like this, but something that will also be durable and hold it's shape well.

Hopefully I have posted this in the correct forum, if I have not, please let me know where it should have gone, and I will pull it down and put it where it belongs.

Thanks in advance, and I look forward to hearing about your experiences,

Taltuu

look for Rafal Fett's templates.
They are easy to uses and very accurate.
I have seen very nice helmets that a had a modified plastic baseball helmet for the dome.
the bottom can be done very nicely with sheet plastic. Go to a sign shop and ask what they have for scrap.

Thanks for the input. I am using those templates. I was just hoping to find a way to do the dome, that was a little more one piece. Plus, if I can get the mold right, I could do it many times if I need to. I assume like Lay's Chips, I won't be able to make just one.

Great suggestion on the sign shop. I actually work for a company that makes LED billboards and signs, and didn't even think about sign shops. I probably should have. Great tip. Thanks

Hell, been a member for years and don't have the know how,or tools to make a bucket. That is a worthy project you started. My bucket (if I had one) is off to you. Good luck with it, hope to see a WIP soon.

If you're looking to just create a solid buck that you can mold and rescast later, then you're pretty much making a really nice slice template. Often those are filled with foam to give the majority of the bulk and then finished with bondo on top. Volpin's helm of yngol build used that method if you'd like to look more into it.

As for forming plastic around it.. ehh. Unless you do actually vacuum form it (which would turn out very well), then it would probably be impossible to manually heatpress plastic around it. You wouldn't be able to keep the whole sheet heated up at once, and what you could would probably be very warpy and want to fold over on itself. It'd work if you did it in many very narrow strips or something, but you might as well use a rafalfett or other template by that point (your model would make a nice guide for it though). Fiberglassing it would probably work best, but that will come out pretty lumpy and kinda kill the perfect shaping you've accomplished.

All in all, this would be absolutely perfect for making solid bucks you can mold or vacuum form, but if you can't do that stuff then this might be a bit more difficult of a build strategy than just using a standard template method and using your model as a reference/shape-guide.

I've tried heating up plastic by hand and forming it over a mold and it didn't work very well at all. The problem is, aside from dealing with compound curves which is an entire pain in the arse in its own right (try forming a piece of paper over the bottom of a bowl and you'll get the idea real quick), is that the plastic doesn't want to comply even with the heat gun.... and if there's no suction coming from underneath pulling it over the mold, it just won't keep the shape you're trying to achieve. You really need the combination of heat (a higher heat source than a heat gun) and strong suction.
As for vaccing, it is impossible to vacform an entire helmet in one piece. I mean, you could do it but you'd get webbing all around the helmet on the sides. Assuming you were even able to do that (which you can't, without webbing), you'd still have the issue of removing the plastic from the buck due to those cheeks being undercuts.
You'd have to vac the dome and the other parts separately (which also means 2- 3 molds depending on how you split it up). Then you'd have the fun of trying to match up the pieces in assembly, hoping they'll fit. It just doesnt work very well, which is why helmets are typically made out of resin/fiberglass. Grimm, not sure what you meant by 'glassing it being lumpy, I've seen tons of helmets in fiberglass that are perfectly smooth.

Now if you're doing a one off (or even for molding purposes), I'd recommend something like this being printed and cleaned up, rather than trying to vac it. It would be much easier, albeit still a fair amount of work with cleaning up all the print lines, etc. Then there's the task of molding of course.
Either way, whatever you decide, best of luck to you.

redkraytdragon said:

Grimm, not sure what you meant by 'glassing it being lumpy, I've seen tons of helmets in fiberglass that are perfectly smooth.

Click to expand...

I meant fiberglassing over the top of his dome template, like glassing on the outside of a mold instead of the inside. It'd work over trying to heat press plastic over it, but it'd of course need a lot of smoothing work and would oversize the dome.

Ah ok, I gotcha. Yeah, that wouldn't work very well, not really a good way to go about it. And too much sanding. There are much easier ways than that.
I think 3D printing or a CNC model would be the way to go for this particular piece.

Thanks for all the feedback guys. I was only planning to do the dome this way. I would love to build a vacuum former someday, but I do rent right now and don't have the shop I plan to have in the future. I make due as best I can out in my garage, but still not a lot of space out there.

Grim, thanks for the suggestion of filling that dome with foam and then using some bondo over the top, that would make a nice form for the Vac puller someday.

RedKrayt, I agree, it would be impossible to form the whole helmet. I was really hoping to just find a way to produce a dome that would work with the rest of the bucket. i am building a bucket from Rafal's templates right now, and was hoping to incorporate a one piece plastic dome with it. Would have been nice to have a dome that was somewhat easy to reproduce and not have all the seams. But, it's alright, I'll just take my time and enjoy the whole process..

As, I have never done anything like this before, I really appreciate all the feedback. I am having a lot of fun so far, and look forward to getting the template pieces all put together.

If you make a solid dome buck, you should be able to vac form it. It's short enough to where you won't get any webbing. Just make sure you make the mold tall enough (but not too tall) so that the plastic can draw down past the bottom of the modeled part. If you don't, you'll wind up with 'draping' and won't capture the part of the mold you want.....hope that makes sense.