I never liked the idea of placing something like a velcro strip or a tape onto my 580EX flash, so I decided to come up with the following gel holder to be used for the flash and the Roscolux Swatch Book of gel sampler. Luckily, while I was shopping for a suitable material for it at a local Lowe's, I found an item that, just with one $2.97 piece, allowed me to create a gel holder as well as a straw grid snoot. But first, some finished product images:
Detachable Gel Holder & Straw Snoot Combo
Attached Gel Holder & Straw Snoot Combo
Gel Holder with Sample Gels
DIY Snoot: Severe Weather 2"x3"x5-5/8" Downspout Coupler
This downspout coupler is just perfect for a project like this, because it's as light or even lighter than an empty macaroni cheese box and yet hundred times stronger. This coupler gets cut in half about 1cm below the first (going from larger to smaller) crease, the larger end to be used as the gel holder and the smaller end for the straw grid snoot.
Roscolux Swatch Book Sampler and Self-Seal Laminating Pouches
You can also use an 8x10 laminating sheet and do several gels at the same time...