k so i broke down and bought another dang glue gun! $5 at home depot for the small "crafts" version btw. another $5 for a 25 pack of glue sticks.
the pre-existing frame and this insulating/reflecting material we had left-over from installing our floors. i was planning on building a dog "house" out of it but this project had priority!

close up of the material. the bottom is the white part and looks like very thin foam. top is much thinner aluminum foil

the entire gluing down was a pain in the neck. i did plan on regular aluminum foil to cover the bottom but turns out we ran out of it beforehand. i should have looked for a spray-on adhesive. would have been done in 5 minutes rather than 40.

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light tryouts edition 1!
the lights i had in mind:

the results:

i was not impressed. thats 3 strands and still pretty weak.
next competitor: some lights i had laying around:

in this pic they are the bunch of lights at the bottom. brighter but not apparently so in person.

final contestant for the night: our house christmas lights!

much better brightness but they're encased in a plastic "icicle" housing. in other words they're directed in one direction and its not the right way. i could break off the icicle and perhaps then it'd be bright enough but that'd ruin these pretty expensive lights.

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so glued on shiny material. failed to find decent lighting. will be looking for more lighting options this week. will look into those LED light strands that are the LED's themselves.