Flex Watt Mfg says NO to foil/aluminum tape

Radiant heat panels are fairly different from heat tape in that aspect. They use radiated heat, rather than conductive heat if I am not mistaken, hence the name radiant heat panel. Then there is heat convection, which is what many of us use for our incubators when we install DC fans to spread the air around. Head dispersal by flow of liquids (air included) is convection.

Originally Posted by stevek

Robert any issues with it wearing out from the tubs going over it?
Do you cover the top of the tape with it?
Have you ever tried to remove it from the tape and is it a sticky mess?

Thanks for the reply.

The heat I use duct tape on is back heat, so no issue with wear. I did cover the top of the tape with it, no problem there. I have not tried to remove it, but I'm sure when I do it will be a sticky mess...though the sticky mess should be easy to clean off melamine when the time comes.

Mike do you put the kevlar tape on the bottom of the flex watt and over the top, or just to hold the flexwatt down on the sides?

Thanks!

Originally Posted by btbutler

No you are fine, don't worry . If you arent touching the conductor of the heat tape with the foil tape, it would be next to impossible for the heat to transfer in the foil tape, except for the radiated heat that comes off from the tape, which wouldnt be much. The main type of heat that you are trying to get out of heat tape is conductive heat, which is why you have the heat tape touching the tubs in a rack system. If the foil tape is not directly touching the conductors on the heat tape, there will be little to no conductive heat transfer, which would mean that you couldn't create hot spots. Is some of the foil tape going to be affected by the radiated heat off of the tape, yes. Is it going to be in temperature spikes of 10+ degrees, no. You may have a spike of somewhere around a couple of degrees. If you touch the plastic edges of flex watt, you will notice it doesnt get anywhere near as warm as the center conductors. This is because metal is an excellent conductor of heat, and plastic is relatively poor at conducting heat. Hence why we insulate houses with fiber glass and styrafoam. Generally speaking, if it is a poor electrical conductor, it is a poor heat conductor. Vice versa. Good heat conductor, good electrical conductor.

My tubs slide across flexwatt and aluminum tape every day. It hasn't worn in the last couple years and only produces a light lead colored dust that easily wipes away. This dust does not appear to come from wear. Aluminum tape doesn't leave a residue behind when removed and is more dependable with temperature fluctuations. Duct tape will decay over time and dry out unfortunately, which is weird because its the worst thing to use on ducts.

If you install your flexwatt correctly, you will not be shocked. Everytime you use a piece of heat tape, there are four connections you have to seal, two for the wires and the two on the opposite end where you cut it.

Originally Posted by stevek

So I'm curious as to what "others" here use under their flexwatt tape, to secure the sides of their flexwatt tape, and on top of the flexwatt tape (if anything).

Want to reflect as much heat upwards toward your tubs?.....The Mfg says using a foil tape on the bottom creats a "heat sink" and actually draws heat downward to be absorbed to whatever the tape is attached to. He recommended using a sheet of rigid insulation (like blueboard) that is made not to absorb heat.

Missed this part, the only thing under my flexwatt is melamine. The fact that heat rises and often takes a path of least resistance, it rises just fine.

I use the aluminum tape on the three sides that do not have the wires. It's just my theory, but I think letting it breathe will reduce hot spots and help the heat rise rather than heat the shelf. When it's taped flat against a surface, it can't help but to directly transfer the heat below, at least to some extent. Allowing a vent on one side seems to keep the shelf cooler.

Nothing goes on top of the heat tape. With proper periodic inspections, it should be fine a long time with tubs rubbing on it. I examine mine once a month.

*Off topic - duct tape is a name that was adopted over time...the original name of the product was duck tape. Today, you can find products labeled either way.

If we're going to go with what the manufacturer says (I've just been waiting for a chance to point this out, lol, but haven't wanted to start a new thread to do it) Calorique heat tapes should not be placed vertically (think back heat). That bit of info is listed somewhere on their website - the warning about foil tape is there, as well - I think it was in the section about floor warming.

I've previously used Aluminum tape on flex watt. I just made sure the cut ends were electrically insulated before covering them. I was never shocked by my flex Watt.

Here is a question: What is the difference between a layer of aluminum tape on the flex-watt compared with it being glued to Galvanized steel panels like the heating elements in professional rack systems like Freedom Breeder and ARS.

One other thing I have done, which has signifigantly increased the heat in the tubs on a back heat setup, is made an aluminum frame for 4" heat tape (5"x48"x1") and taped the heat tape to one side and bought 1" thick insulation board. I cut and packed this into the frame I built and sealed with aluminum tape. This was great for redirecting the heat towards the tub.

So Nick, you're flexwatt is sandwiched between aluminum and insulation board?