I made a boot dryer many years ago, super simple with PVC pipe and some elbows and T's
And some straight pipe.
A single hair dryer is plenty to do 2 boots at a time and I have ran my hair dryer for 8 hours at a time with no issues on low heat
If your temps are too high then pull the hair dryer away from the inlet of the PVC pipe by a couple inches and it will then pull in cool air with the warm from the hair dryer.
Do not over think this.
Another way is to lay the boot on the floor on it's side and lay the hair dryer so it blows into the open boot.
Adjust the distance and if you notice the air will exit the boot and you can place another boot in the path of the exiting airflow.
Yes that works also.
And some straight pipe.
A single hair dryer is plenty to do 2 boots at a time and I have ran my hair dryer for 8 hours at a time with no issues on low heat
If your temps are too high then pull the hair dryer away from the inlet of the PVC pipe by a couple inches and it will then pull in cool air with the warm from the hair dryer.
Do not over think this.
Another way is to lay the boot on the floor on it's side and lay the hair dryer so it blows into the open boot.
Adjust the distance and if you notice the air will exit the boot and you can place another boot in the path of the exiting airflow.
Yes that works also.