It’s a rod heater. For making carbon materials, this has turned out to be one of my most useful tools. When coating paper or making tissue, it’s a pain to have to constantly refresh a tube of hot water to keep the coating rod hot. Often the rod is too cool or the temperature is inconsistent. The hottest water rises leaving the bottom of the rod cooler. All in all it makes for a tedious session
It was simple enough to build. The key component is the heating element. It is a simple electric beverage heater you can get at Ace Hardware. The heating element is stuck through a hole in the black rubber end cap that is attached to the end of the wye fitting. Epoxy glue keeps the hole in the end cap water tight. The wye keeps the element out of the way of the metal rod. The switch obviously turns it on and off.So, for about 20.00 and a couple of trips to the hardware store I was able to make a fully electric rod heater. The only things it lacks is thermostatic control. Maybe I’ll add that feature for v2.
The rest of the pieces are PVC pipe and fittings to suit the dimensions of your coating rod. I’ve found that 2″ pipe is more than adequate, but I like the transition to the larger 4″ at the top as it makes the heater easier to fill and the rod easier to grab. The only other price of interest is the base. That is a PVC toilet flange. The wide base allows it to stand upright wherever I want to use it.
To give the heating element a head start, I fill the tube with hot water from the tap and turn it on. However, it will heat a tube of cold water in about fifteen minutes. I keep a check on the temperature of the water and simply turn it off at the switch when I want it to cool a bit. It can make the rod too hot. When I am coating a sheet of Yupo for tissue, a rod that is too hot can cause the Yupo to buckle a little. One thing to remember is to never turn the heater on and pour water on it. The thermal shock will cause the element to break and you’ll be headed back to the hardware store for another heater.