GitHub Media on Headband Production
This link has the photo's and video on the various approaches to the headband production Head Strap Documentation
Every person will find a different technique and length that works for them, as the elastic varies in thickness and stretchiness.
The end-users will have different sizes and preferences, so, giving them some ability to adjust the elastic themselves is the nicest option.
If you are unsure about getting the right length for the different elastic widths, stretch, and attachment type, then test fit the elastic until it feels comfortable and secure on your head. Then add the additional ability to adjust up and down from your fit.
Length varies between visor versions due to the change in design, other users have found an approximate guide for length:
Verson 1.2 Elastic is approx 25cm long for a single strap and 50cm for a double-length
Verson 2 Elastic is approx 30cm long for a single strap and up to 60cm for a double-length.
- The present length suggested for the elastic distributed by ShildsUp is about 45cm
Adjustment and Attachment to Lugs
Button hole elastic is easiest, as you only have to cut to length and fit to lugs, adjustment is built into the elastic.
For all the other types of elastic: cutting slits, tying, or looped end are some of your options of attachment and adjustment:
For thin 6mm elastic, it might not have enough strength, so doubling the length and folding over the elbow in the frame (as shown in video) then tying a knot at the back seems to work well.
For 12mm thick elastic, you can fold over 2cm at one end and sew a loop or staple the fold and attach to frame lugs. You can try cut slits in 12mm, about 1cm long, at least 1cm back from elastic end.
For thick elastic 15mm and above, the same options of tying and folding elastic onto frame lugs, however cutting slits at least 1cm from ends (with additional slits above and below your fit for adjustment) might become increasingly preferable the thicker the elastic is.
If you choose to cut slits in thicker elastic, you can leave extra length to cut a slit above and below your head size slit to give options to the end user. Some elastic types might fray when slit, but most are fine and require less handling and effort than sewing loops, but if sewing loops works better for your elastic type, then do what is comfortable for you.
Store unused elastic using a repurposed filament spool.