How to craft anything from fiber glass composite

Hi, everybody.
I wanted to test and show you a very promising technique of attaching tin miniatures together. Unfortunately, both my Infinity starter pack and materials I've ordered for this experiment are still travelling to my post office. So this time I will show you something else.
This summer I was attending a huge LARP event dedicated to Warhammer FB universe as a dark elf, for that I've crafted several druchii helmets. This post describes the full technological process with some photos. You can use the same technology to make any parts of your larp or cosplay costume, or enything else that should be relatively lightweit, be able to withstand some mechanical punishment and have a more or less complex shape.

Tools and materials:
polystyrene foam - same you would use for terraing crafting;
double-sided adhesive tape (non-fabric);
sanding paper;
utility knife;
foam cutter (optional);
light fiberglass fabric (about 50g/m2);
fiberglass matt;
epoxy resin with hardener;
polystyrol resin with hardener;
a lot of basic cheap paint brushes;
mold release wax;
scissors;
respirator;
electric drill;
electric jigsaw;
a set of m4 nuts and bolts;
utility gloves.



You start with a master model. Glue sheets of foam together with double-sided adhesive to get the needed thickness. It would be easier to cut the rough profile of your design out of every sheet before gluing them together.

Cut a rough shape of your helmet using a foam cutter or a knife. Finish the shape with a sanding paper. Take measurements.

You can take papier-mâché samples to try it on before going into serious business with resins. Just wrap your foam model with a stretch wrap to protect it from glue.
Continue cutting and sanding the model and making measurements until you are satisfied with the result.

After that you must cover the model with one layer of fiberglass fabric and epoxy resin to protect the foam from a corrosive polystyrol resin. Attach your helmet model to a horizontal sheet of foam, prepare prepare a mixture of epoxy with a hardener and apply fabric just as you would do it with papier-mâché. Try not to leave any air bubbles, remove them with a brush or a special metal roller. Use a respirator and gloves when working with fiber glass and resin.

After the exoxy has completely hardened, polish it with a sanding paper. Now start applying the mold release wax. Put one thin layer on the whole model, then give it an hour or so to dry. Then repeat.
You need 6 or 7 layers of wax. If you want to achieve a fine glossy surface of your helmet, you have to polish the wax. I have failed at that. Anyway, it is not necessary at all. Then hou have to set up a separator. The model has a complex shape and it will be impossible to take a complete helmet out of the mold that is made of a single piece. That's why we need to make a mold of two halves. That's why we need a separator - something that will split the model into two halves and give us a possibility to make every half of a mold separately. Unfortunately I don't have a photo of it. Imagine something like this:

This is the trickiest part. I've took a side picture of my model, traced it's contour and sent it to my friend who cutted it for my out of plywood with a cnc laser. Then I used my Dremel to fix the inevitable distortions and attached it to the rectangular base of the model. Your separator can be as thick as you want, it doesn't matter, but you shoud install it in such way that one of the sides precicely coincides with the middle crossection of your model. Of course you should also cover this side with several layers of mold release wax.

After the separator is installed and the wax has dried, you can start making a mold. Start with the side where your separator is waxed. Here you can make another step that I've skipped in my process - apply the gelcoat. It is the special substance that will make the inner surface of your mold homogenous and (if you have polished the wax - glossy). I've skipped this step because I've found it difficult to cover the waxed model with the gelcoat, it just didn't want to stick to it. Perhaps, I've been doing something wrong. After the gel-coat has dried you can start applying the fiberglass matt with a polystyrol resin. Polystyrol resin is not as hard as epoxy, but it is three times cheaper, that's why I have decided to use it for my project. Cut your matt into long strips and apply them to one of the halves of your model. Use the same approach as with the papier-mâché: apply some resin, put the fiberglass on, smear some more resin on top (fiberglass must be completely soaked with resin), remove the bubbles, repeat. In this case you will need 5-6 layers for a sturdy mold. Work quickly and never mix more than ~150 mililiters of resin, it hardens really quickly. When you're done, wait for an hour, remove the separator and apply several layers of wax on the edge of the mold that touched the separator. Wait for it to dry and make the second piece of the mold. After an hour take a drill and make holes around all the "seam" between two halves. Then remove the halves from the model. The result should look somewhat like this:

Now cover the inner surface of the mold with several layers of wax. Be careful, don't leave any uncovered spots. Then screw the two pieces together with bolts and carefully fill the seam with wax. After everything dries, you can start making the helmet. Here you also can use the gelcoat if you want to have a perfect glossy surface, I didn't. Cut the matt into long triangular stripes and start gluing them inside the mold as you did previously during the creation of the mold itself. Four layers will be enough (I think I used a 300g/m2 matt).

After half an hour you can take the helmet out of your mold - just unscrew it and take apart. Use the jigsaw to cut the excess fiberglass and cut the visor out.

Remove the wax from the helmet with solvent. Now you can cover it with enamel paint and add highlights with an airbrush.

You can reuse the mold to make several helmets, just be careful with waxing and don't let any dirt get into your mold.

And be precise with your measurements. I was very afraid of making them too small, as a result they were too big :)