Insulating Pad

[philosofool]

I want to make a simple insulating pad, about 12cm x 12cm, that velcro to the outside of my fermentor over the probe of my stc-1000 temperature sensor. It should be durable, unharmed by water, and provide enough insulation to keep the probe at beer temp as heat works through the stainless wall. Ideas?

 

[snackson]

Little bit of bubble wrap? A sponge in a ziplock bag? Cheap and effective.