When I made a satellite dish out of foil tape and an umbrella, everyone asked if I could do the same with emergency thermal blankets. I decided to give it a try, along with a few other viewer suggestions of metallic spray paint and reflective photography umbrellas.
I was surprised to find that the thermal blanket glued to an umbrella actually does work! I built this quickly and not very carefully, so it could definitely be done a little better.
In addition to the umbrella, thermal blanket, and spray glue, I used the following hardware for this project (these links give me an Amazon commission):