Flex Watt Mfg says NO to foil/aluminum tape

Originally Posted by R. Eventide

I have been mostly referring to thermal conductance, not electrical conductance, since we're talking about heat, and Al tape is thermally conductive:
http://solutions.3m.com/wps/portal/3...6/AlumFoil425/

Plus, the tape is extremely thin, so any overlap will be insignificant in terms of causing hot spots.

Couldn't have given better proof of this point. Good post Krystal!!! Everyone should read the info given in the link. All of the things listed by 3M are things we are looking to achieve by using heat tape in combo with aluminum tape. As stated in my earlier posts, just don't touch the electrical conductors with the aluminum tape, and you will be fine.

I'm looking at a concrete board meant to go under tile to sandwich 11" heat tape between. It seems dense enough to be a good thermal conductor but I'm worried it might be impregnated with a lot of fiberglass for strength and be a better insulator than I think. Can't imagine it would conduct electricity though.

Here's what I think is a partial solution. Got myself some plastic hardware cloth 1/2" grid. This can go on top of the heat tape and the tubs can slide over this. This doesn't solve the issue with the old style racks where the tape bows up. The tub height space btw tub top and the shelf above it are too small to allow the addition of this plastic hardware cloth under the tubs, at least on my rack.

I'm an idiot. I like it simple. Can we use the aluminum tape under the heat tape and cover the entire heat tape on top except for the end where we connect the wires and the other end where we cover with electrical tape? Simple question, simple answer, yes or no, please. Thanks Ron

Originally Posted by RonzRoyalz

I'm an idiot. I like it simple. Can we use the aluminum tape under the heat tape and cover the entire heat tape on top except for the end where we connect the wires and the other end where we cover with electrical tape? Simple question, simple answer, yes or no, please. Thanks Ron

Realistically, don't put it under your heat tape. It will cause a heat sink at the bottom. Putting it over the top you can also do, just watch for rub on the heat tape. Then yes make absolutely sure that the aluminum tape isn't touching the conductive leads, as well as insulating the ends with the plastic connector covers and electrical tape.

Thanks Brendan, I had aluminum tape under and over, but not touching the ends. Because of all this, I put painter's tape under and on the edges of the top to hold it down. I'm gonna change the top back to a.t. without touching the ends. I didn't think anything was wrong with the way I had it, but reading everybody elses comments, I changed it.

I hate just having the tubs slide over the flex watt on my old style racks where the flexwatt rubs against the sliding tubs. I can't help but think covering the flexwatt for protection with anything will trap heat. So is the general opinions here that aluminum tape on the top of the flex watt is OK, but below is not?

Originally Posted by stevek

I hate just having the tubs slide over the flex watt on my old style racks where the flexwatt rubs against the sliding tubs. I can't help but think covering the flexwatt for protection with anything will trap heat. So is the general opinions here that aluminum tape on the top of the flex watt is OK, but below is not?

Because of the high thermal conductivity of the aluminum tape, you would be drawing some of the heat out down to the bottom if you had the aluminum tape on the bottom. whereas if you just have it on top of the tape, you are creating a protective barrier from friction from the tubs, as well as creating a heat sink on top of the tape, which is where you want the heat to be right? Touching the tubs. Exactly. This is why it would be ok. Wood/melamine has a low thermal conductivity and would not create a heat sink on the bottom of the heat tape, whereas the aluminum tape is very thermally conductive and would most definitely create a heat sink.. To express the idea of what is more thermally conductive, stick these three objects into a cup of either boiling water or ice water

-a pencil (wood)
-a straw (plastic)
-a nail (metal)

make sure the tops of each are sticking completely out of the water so you can touch them with your fingers. let the objects sit in the water for a few minutes. you will find that object made of metal is going to be very close to the temperature of the temperature of the water itself. The wood and the plastic really wont be anywhere near the temperature of the water. you may feel some temperature change in them, but it wont be much, and this is because they are non thermally conductive materials. Metal is very much so thermally conductive (i.e. aluminum tape.)

I always use foil tape and have never had a problem. just make sure were you attach the wires you wrap it in electrical tape. I put down the flex watt and completely cover it with foil tape, and it works great and saves your flex watt from wear. Just stop the foil tape short of the connections.

yeah I always silver soder and tape my ends well.