@suomalainenolio The mirror has to be convex. If it's flat (or worse, concave), it won't bounce the light "out" toward the dish. It would bounce straight back toward the flash.

@PEARLPHOTOS This is the 3' Creative Light Octabox. I don't want to go much bigger than 3' with a speedlite because it will start seriously diminishing it's effective range. And 3' is pretty big, especially for my purposes.

Shoud the mirror or reflective surface be flat, convex or concave ? Haha hope google translater gave me right words xD. when i watch other videos like this , someone but flat , other convex and etc..

sand area down before applying the silicone. and you can smooth it with washing up liqud/soap.

Regular aluminum downspout? Cut it a little longer, about an inch. Tin-snip the corners down an inch then flange all four sides to 90 degrees. Drill the flanges to the base so the holes line up. I'd say use eight (two per side) real short 1/8" nuts and bolts. Maybe get a piece of sheet rubber traced to the hole as a gasket to block out light. By the way, this is awesome. Compliments to the chef.

You should make more and sell them on ebay :P id buy one!

@calebkerr17 Thanks