The first thing I did was sculpt my bio helmet. I took a foam head you buy at any craft store, a party mask, and some sculpting wire, to fashion a base. It wasn't perfect by any means. I'm sure there are better ways to go about it than how I did.
Now that you have your base, you need to sculpt. Use oil based clay, that way it doesn't dry and you can work on it for as long as you need. Start off with a base, then start carving into it. I highly recommend watching some videos on youtube to get you started. Also, have plenty of reference images nearby.
Continue to refine and sculpt until you are happy with it, or you run out of time (like me!).
From here on out, I used this video to make my mold. He has a series of videos for making a bio helmet, including sculpting. Unfortunately, I didn't find his stuff until after I was ready to mold. When molding, I recommend you pay close attention to the ratios you need to use for the silicone. I messed mine up the first time so my first layer didn't cure. I was able to mix the second layer into the first and get it to cure the second time around, though. I used this silicone for my mold.
Make sure you make your silicone thick enough. I did not. Therefore, my final mold didn't cast as nicely. Also, let it cure completely before moving on to the next step. Watch the video and follow his instructions. After the silicone, you need to make a plaster case around it. I mixed my plaster according to the directions on the bag and it was too thick. It wanted a 2:1 ratio plaster to water. I recommend starting with a 1:1 ratio, and adding more plaster if needed. It worked, but wasn't very easy to work with. Also, don't forget the burlap pieces for stability.
Let this dry completely. Now, you are ready to cast. Because my silicone wasn't thick enough, it pulled away from the sides and I had to clip it in place. This caused a few minor deformities in my final pull. I'm lucky it worked. To cast, you need resin. I used casting resin, but the video used regular resin. I bought my resin before watching the video. Rookie mistake. If you go his route (which I recommend), ignore the following paragraph.
If you went my route: It was a bit difficult getting the resin right. First, the resin and the catalyst are sold separately if you buy them at Michaels, so don't forget your catalyst. Second, I recommend working in small batches, because it gels, it does not thicken. So you have to spread it around while it's smooth, and therefore you have a lot of pooling. I worked in 1 ounce batches (my face is small, therefore my helmet is small) and used 15-20 drops of catalyst per ounce. I also leaned my mold all around so the pooling would happen all over the place, and I wouldn't have thin spots.
Make sure you do plenty of coats, so it's thick enough that it won't break. Also, do not up your catalyst too much or it will crack as it dries.
Now, to pull the cast, be very careful. Work in small steps. Loosen the resin from the silicone all around your mold. Eventually, the silicone/resin will pop out (or at least it did on mine). Then, simply peel the silicone off the resin. I did not use mold release, and had no problem getting my mold out of the cast.
I highly recommend tinting your resin. I had to paint mine black to be able to see what needs sanded.
I'm going to finish the tutorial here. All that is left is sanding and painting. Also, mine luckily fits snugly on my head. If yours doesn't, you will need to devise a way of keeping it on. I recommend a headband and magnets. Good luck!
Until next time, keep cosplaying! Any questions, comments, or requests, leave them below!Instagram