DIY Wonder Woman Cosplay - by Becka Noel. Step 4: Now that each foam piece had its Worbla partners, it was time to heat it up, meld together. I started with the shoulder piece, which consisted of two pieces, a large piece, which curved on and around my shoulder, and a fin, which stood up perpendicular to the shoulder. After heating up my large piece, I pressed around the edges of the Worbla to seal them together and cut it out. Then, more heat (I use a Wagner 1,200-watt heat gun)