Below is a shot of the bottom of the plane showing the DT or dethermalizer system.
Starting at the right side is a Badge Timer (purchased from Starlink Flightech Models currently selling for $19 (price includes a DT spring). A 3 pack of DT springs are also sold separately for $5 Both can be found at web page: Starlink Flightech Models/badge-timers. To make the system, I use upholstery thread I purchased from Walmart. It comes in various colors so I use the least conspicuous color depending on the tissue color.