Gentle heat

[bryverine]

I currently have a lightbulb as the heating element in my tarantula closet. Originally i was considering a large tank of DI water with heaters to gently heat the area.

What would be the drawbacks of doing a sealed/closed system something like this:

I'd be worried that:

1. sealing with silicone and thermal expansion could be an issue if I don't leave a bit of room for an air pocket.
2. Melting/softening of the plastic. Generally soda bottles are PET and have a glass transition temp of 150°F. I'd prefer a milk type jug but they're made of HDPE and its much softer...

Thoughts?

 

[viper69]

Experiment somewhere where you aren't afraid of a fire, or melting plastic. Expansion due to heat would be my concern, be it gas or liquid.

 

[The Snark]

Thermal expansion is always an issue in a sealed system.
PET and HDPE both lose plastic properties with repetitious heating and cooling, becoming brittle.
Better option is glass of course, preferable Pyrex. Best would be tempered but we are talking lab glass at about the price of gold.

Alternative would be ceramic or cement. They act as thermal batteries so temperature will remain at a more constant level. The down side is thermal batteries can be a beast to dial in.

Keep in mind with purely resistive elements a typical household light dimmer can control the heat output as desired. Most are good for 15 amps - 1600 watts.

 

[StampFan]

If you can put a space heater on for an hour a day heating the "closet" with decent insulation you may be okay for the rest.

How cold is the closet at its highest and lowest? You always have to start there....