Here's mine for AT115EDT. Local craft store provided needlepoint hoop for base, needlepoint fabric, posterboard, black foam sheet. I had glues, tapes, Velcro pads and black acrylic paint. Bought 90mm square of Baader Astrosolar film from Agena. Hair, feathers, guts and all for < $30.
This is going to read like it was complicated but it was easy.
That's it. Light tight w/o any leaks. Front piece larger diameter than main body to shade the scope tube. A Scopestuff.com solar shield (not pictured) shields the observer pretty well.
This shows construction. The hoop's made to secure the fabric so I cut an oversize hole @ 90mm in the fabric, mounted it centered in the bore, torqued down the hoop's fasteners, painted the fabric thickly with acrylic to stiffen it, cut posterboard circle to match hoop O.D. with final aperture of @ 83mm and stuck that to the front surface of the doped fabric (the front surface of this ring is where the film mounts), cut wide strip of posterboard to make cylinder to slide over scope dew shield and glued it to inner bore of hoop, cut strip of black foam and glued it to inner bore of paper cylinder, mounted solar film FOLLOWING INSTRUCTIONS ON BAADER ASTROSOLAR FILM WEBPAGE, cut front piece from posterboard to match aperture and glued it in place w/o restricting film, used small Velcro tabs to get final fit of dew shield to inner bore and DONE!
Here you can see the black foam makes a boss for the dew shield to seat against securely. And the Velcro discs are seen.
Note the bumpers made from the foam that keep the box lids from contacting the Baader film and keep the filter and housing from bouncing around. Cardboard was added to the inner box walls nearer the bottom to match the housing O.D. for secure fit.
EDIT - It works very well and is about as safe as you'll likely find. I secure the filter housing to the dew shield with a piece of gaffers' tape for outreach events just for extra insurance against someone fiddling with it.
Edited by havasman, 15 October 2019 - 03:35 PM.