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06 Mar 2013 - 11:0498270
Fiberglass Pepakura or Expanding Foam?
So I'm currently working on making Screaming Mantis from MGS4:

I'm going to start working on the Helmet portion soon and I have two options for going about it but I'm not sure which would be the best so I'm basically putting this here to pick other peoples brains really.

The two options I am toying with are:

a) To make a Pepakura version out of cardstock and then fiberglass this. I currently have a file for a daft punk Helmet which is similar which I will need to modify to make it more exact but it's close enough.

b) Use expanding foam to sculpt a base then add finer detail in either clay or two part epoxy resin.

I've heard if I use technique A and I fiberglass on the inside I can directly rotocast the helmet but I can only use this mould once whereas with technique B I can make a silicone mould and use this multiple times if I stuff up my rotocasting

Also it's worth noting that Fiberglassing is new for me but so is expanding foam so this is the other dilema. I've used Pepakura and clays before though

Thanks in advance for looking - any thoughts on this would be greatly appreciated even if it's just personal experiences

Last edited by gaming_goddess (06 Mar 2013 - 11:09)
06 Mar 2013 - 21:3498351
I can't give you much advice (you've probably been to all the same prop and armour tutorials I have XD) but it might be worth looking at Xae's Briareos costume:


as he did that with hot glue and layers of latex which is another option that might work for you ^^

07 Mar 2013 - 00:2098383
Yeah xaerael always documents stuff so well. I do have a lot latex and hot glue lying around from another project so might give that a shot!

And yeah been lurking RPF a lot so getting lots of details from there


11 Mar 2013 - 10:4898758
I'd go in another direction and probably try heat-formed plastic. It depends a bit on how you're planning vision out of that thing! I would look at a clear thermoplastic sheet (you can get them at a lot of larger art and model shops) and motorcycle visor tint sheet to get the colour - that way you'd be able to see through the full helmet (if darkly) although you risk your own face being visible through it too, but you could use a balaclava to cover everything but your eyes underneath it.

I haven't thermoformed the stuff myself, but I know it's what Tab used on his Crystal Siegfried armour, so it's definitely possible, and I believe he only used a heat gun to do it - so no fancy equipment needed.

If you have other ideas on seeing out of it (and I will DM you later about that) I'd honestly take a look at doing it out of Plastazote and PVA, like TheKillingDoll's Priss armour. It's also heat formable and you can make it look nice and smooth, plus it's friendly to work with.

Xae would tell you to avoid fibreglass like the plague. He tells everyone to avoid fibreglass like the plague. It's not friendly stuff at all and you need really good Personal Protection Equipment to even consider using it safely, so look into every other simpler and safer method first >_<

12 Mar 2013 - 10:5598809
Cool I will avoid the Fiberglass. I wasn't very keen on the idea of Fiberglass because I've heard it's nasty nasty stuff but I kept seeing it pop up in build tutorials that I was kinda intrigued by everyones fasination for it

I love the idea of using tinted thermosetting plastic. I'd not even thought of that. I used wonderflex in the passed and had a bad experience with it because I burnt it. I think it's more to do with the fact that my heat gun was way too powerful for it. I also had the same problem with Plastazote but I've been planning to buy a new heat gun for a while so as long as I'm careful I can avoid that Especially since I've seen all the wonderful things people make with it - I mean I attempted using it a long time ago as well so all the new stuff I've learnt should help.

And I don't mind my face being seen - it's a better option then the ones I had thought of. So far all I could think of was having the helmet flip up like it is after the boss battle for most moving about. Then having it pulled down just for the masquerade and having small eyeholes that you kinda pop out. I will get looking for some visors that might be a good base on eBay and if that doesn't yeild anything I'll get heading to a good arts and craft store near me

Thanks for the help

13 Mar 2013 - 21:4698951
Fibreglass is a lot of glue. Having used it a bit, it's okay in a well ventilated area with gloves - but get a book on it to be properly safe with it (mixing things wrong is a bad idea; think a more complex epoxy with very specific measurements).

The fact you might want to make more than one means yeah, use this as a last resort, since if something goes wrong when making the final piece it'll be starting from scratch doing a mould (one reason I'm avoiding it for my current costume).

You can get reusable moulds that work with fibreglass things, but just need hardier material. Helmets are a pain though.

14 Mar 2013 - 12:5498983
Thank you for the advice. Something more complicate then Epoxy sounds out of my league to be honest. Unless its a 1 to 1 ratio I mess up so this is just another reason to avoid fiberglass by the sounds of it so thank you for the advice.

20 Nov 2013 - 19:39109213
Sorry to bounce an old thread, but this thread comes quite when you google "fibreglassing expanding foam" so for anyone else that arrives here:

Just tried it and you can't.....the resin melts the foam. This was with the foam wrapped in cling film and then heatshrunk, so fairly (but clearly not entirely!) well sealed.

Back to the drawing board...shame because expanding foam is great for making simple shapes with

20 Nov 2013 - 20:27109215
Quote markvr:

This was with the foam wrapped in cling film and then heatshrunk, so fairly (but clearly not entirely!) well sealed.

Anything plastic tends to get taken out by resins, I do resin work frequently and left a plastic spoon in a disposable cup for stirring on the side, I came back to it the next day with a bit of resin in the bottom and the spoon was melted, so cling film is pretty much doomed upon contact.

My dad recommends Visqueen (http://www.visqueenbuilding.co.uk/) because it doesnt stick to the fiberglassing, you could wrap whatever it is, even in strips and place it over the top. Also try doing your mix at 1% activator. It'll take longer to go off and harden so leave it well alone, especially in this colder weather. But it should help you out.

Last edited by Angel Tear (20 Nov 2013 - 20:27)
21 Nov 2013 - 19:10109226
Cool thanks for the info, might try wrapping it in aluminium foil next time I think, because I'm a cheapskate and already have some but thanks for the heads up.

07 Dec 2013 - 14:06109457
Just like to chip in my 2 cents as I've worked quite a bit with fibreglass in the past.
In terms of expense, it's not cheap but it's not expensive either. You wouldn't need to save for it, but you wouldn't want to waste copious amounts of the stuff.
In terms of using it, it comes in several parts:
The actual fibreglass material. It comes in sheets and can be cut to the size needed. It's important to note that it isn't kind to bare skin so gloves and long-sleeved shirts are recommended. It's classified as an irritant, but you don't need specialised protection - household items would do the trick.
The fibreglass resin. Has one heck of an odour, so either working outside or in an extremely well-ventilated area is highly recommended.
The catalyst/accelerator. Once mixed with the resin, darkens in colour and begins to solidify. This stuff doesn't last long once mixed. Depending on the recommended mixture ratio (I've always used 1:100) you have about 3-4 minutes before it becomes completely solid.
For this reason, it's important to use disposable equipment, as whatever's coated in the fibreglass will be virtually unusable afterwards.
It's something that does take practice to get good with. However, the foremost advantage of fibreglassing is durability. Whatever you use it on will be solid as a rock. People can smash into you, you can drop it on the floor, you can leave it to get crushed at the bottom of a suitcase etc. and it'll survive no problem.
I picked up my first fibreglassing kit in Halfords for a fairly reasonable price which included all the above plus mixing syringes and containers.

Procrastinate Now. Don't put it off!
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