Welcome back to this series on making a foam helmet from a very simple pattern. Part 1 of this series, Getting Started, can be found right here.
Now that the two pieces of the band have been joined together with Barge contact cement, it is time to shape the band. Because I am using rather thin foam, it could just be bent into shape and the edges glued together, but I would rather put the shape in the band itself. Therefore, I heated the band with a heat gun.
When the foam is warmed, it softens and can be easily formed. When it cools again, it will retain its new shape. When you are forming your helmet band, be sure to remember that your head is not round. Heads are oval shaped. Hold the foam in the shape you want it to be as it cools.
I want a nice smooth curve around the entire piece. That means paying close attention to the ends of the foam strip. It is easy to curve the middle of a long strip, but not put the same curve into the very ends. If that happens the helmet will not look right when it is sitting on your head.
To help with this, I decided to go ahead and attach the ends of the band together. You can do this because it is foam and so will bend. I want to make it look like the attachment is made with a small sheet of metal riveted on. For that plate, I used another piece of foam cut from the 2mm thick foam sheet.
Creating the attachment like this is also great if you need to slightly readjust the size of the helmet after you have made the band. If you need to make it a little larger, the attachment piece will cover any gap and no one will ever know. I made the attachment piece a little shorter than the band is tall because there is still the top of the helmet to be attached.
A helpful hint to follow when you are cutting from a pattern is to cut the line off the material. Otherwise what you cut out will be larger than the pattern. I use a rather thick black Sharpie marker to draw my lines. I don’t want to add the thickness of the marker line to the shapes I am cutting out – especially if they had been precisely measured.
I attached the band with its back plate using Barge cement. I use the same technique of applying the cement to both sides of what is to be attached, allowing it to dry until tacky, applying a second layer if necessary, and then pressing the pieces together firmly.
Then I use the cement to glue the plate to the back. I also realized that I can make the joint on the side stronger by reinforcing it with another piece very similar to the backplate, but this time putting it on the inside of the helmet. No one will notice that it is there.
Once you are at this stage you can pick up the helmet and look at it to see where the band needs additional shaping. In my case, it was certainly near the joint. If the band is not too hot, you can let it cool on your head to get the perfect shape.
If your heat gun has a “cool” setting as mine does, then you can speed the cooling of the helmet by hitting it with cool air while it is on your head.
See you for Part 3.