Putting foil tape UNDER the heat tape?

I see some posts where people are told that they tape over their heat tape too much with foil tape, covering too much, and that the foil tape reflects the heat down, so that more heats up the tape itself and less gets to the tub.

So I was thinking. What if I lay down a layer of foil tape ON THE SHELF first, before putting the heat tape on top of the foil? That way, more heat will be reflected UPWARDS towards the tubs, and the heat tape won't have to run as hot to achieve the same temperature?

I got this idea because I saw some heat mats available where they include a special bag to put over it, the top being transparent material, and the bottom being aluminium, so as to direct the heat upwards towards the tank/tub.

What are your thoughts?

Also, for those of you who put the tub directly on the heat tape, when you guys say you have your tubs "touching" the flexwatt, do your tubs have raised edges or little bumps on the corners? Is the tub really "Sandwiching" the flexwatt onto the shelf with no air space? I have these tubs that have a tiny little raised edge that goes all around (not bumps or legs, like a ridge that goes around the whole bottom side), that is probably half a mm thick. Since there will be water bowls etc. in the middle weighing down I bet the middle will have some parts touching the tape too. Is this OK?

Covering it will cause the heat tape to over work and get extremely hot under.

Test it out by taping it and putting the probe on the foil tape. You will notice the surface of the foil is the desired temps, but under neath its HOT.

I didn't mean tape OVER it I meant tape UNDER it, on the shelf. But I just watched a few youtube videos, and apparently lots of people do that already so I guess its not my great new idea like I thought it was LOL!

A lot of people do put foil tape under the flexwatt, but the guys at spyder robotics recommended against doing that when I talked to them about it. The main reason not to do it was that if the flexwatt failed and melted, then the foil tape underneath would cause a short circuit in the AC line immediately. So,I don't put the foil tape under for that reason and also at my house the flexwatt was "buzzing" only when it was over metal, such as the foil tape, and apparently this was due to harmonic resonance, which happens at some locations because of the AC frequency. Just my experience and 2 cents. . . .

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Originally Posted by Steve-J

A lot of people do put foil tape under the flexwatt, but the guys at spyder robotics recommended against doing that when I talked to them about it. The main reason not to do it was that if the flexwatt failed and melted, then the foil tape underneath would cause a short circuit in the AC line immediately. So,I don't put the foil tape under for that reason and also at my house the flexwatt was "buzzing" only when it was over metal, such as the foil tape, and apparently this was due to harmonic resonance, which happens at some locations because of the AC frequency. Just my experience and 2 cents. . . .

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How about using the foil tape OVER the flexwatt on just the edges to affix it in place on the shelf? Does that cause the buzzing problem and if the flexwatt did melt would that not cause a short circuit just the same as having foil UNDER it would? Do you not use foil at all, whether under, nor above/on the edges?

I do use foil tape to hold the flexwatt to the shelf, and it does just barely cover the edges, I have a couple of friends who are very particular about the foil not covering anything except the clear plastic, but I have a few shelves that the foil is over the silver (colored) AC runners and it doesn't bother me. the whole idea of it melting and shorting out applies when there is a conductive material that spans the gap between the silver (colored) AC runners, with the conductive material running along the edges there is no contact between the two separate AC lines (hot & neutral). As far as the buzzing, when I had my issue it only happened when the flexwatt was running on a t-stat set to proportional mode, it didn't happen at all in on/off mode. , also the buzzing is a kind of rare occurrence, I'm just one if the lucky ones:D it 's a weird freak occurrence that only happens in some houses, tons of people use flexwatt over a conductive material without any buzzing. Extra note on the shorting out possibility, the high end racks like freedom breeder use flexwatt on a metal strip (I don't have one so someone who does can correct me if I'm wrong) and it doesn't seem to pose an issue. I'm just telling you the advice that was given to me regarding foil tape and flexwatt, as you saw on YouTube, lots of people put down foil tape under their flexwatt. In the end you have to choose what's best for you.

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Originally Posted by hungba

for those of you who put the tub directly on the heat tape, when you guys say you have your tubs "touching" the flexwatt, do your tubs have raised edges or little bumps on the corners? Is the tub really "Sandwiching" the flexwatt onto the shelf with no air space? I have these tubs that have a tiny little raised edge that goes all around (not bumps or legs, like a ridge that goes around the whole bottom side), that is probably half a mm thick. Since there will be water bowls etc. in the middle weighing down I bet the middle will have some parts touching the tape too. Is this OK?

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The tubs can sit directly on the flexwatt with no issues.

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Originally Posted by Steve-J

the whole idea of it melting and shorting out applies when there is a conductive material that spans the gap between the silver (colored) AC runners, with the conductive material running along the edges there is no contact between the two separate AC lines (hot & neutral).

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Hey there, thanks, does that mean that you can put the foil tape over the metal "rails" that carry electricity, as long as the foil doesn't go "across" from one metal strip to the other? Is that what you mean? i.e., there are two metal strips which the wires attach to ALONG the flexwatt, and it's ok to have foil over EACH strip, as long as there is no foil CONNECTING the strips?

You know, come to think of it, why use foil tape AT ALL?

I mean, it's metal, it conducts electricity. Other than to reflect heat upwards (when you tape under it), why do people use foil tape to affix it, and then try to avoid the electrical parts or whatnot? Why not just use a non electrically conducting tape like electrical tape etc.? Is it just because foil tape is nice and wide, doesn't melt like duct tape and is nice and shiny?

There are not many tapes as sticky and durable as good foil tape it is very good tape that is why it gets used. I have tried foil under heat tape and it seemed to work well. I am very careful to inspect the tape every month when I clean. I am have extra to replace any that is worn.

Yeah the thing is though I am researching and I see all these posts about people having buzzing sounds from their flexwatt when using proportional thermostats (while other people do the same and do not) and warnings of what would happen if the flexwatt plastic covering melted and the foil created a short etc. Granted a lot of people have no problems just like some drunk drivers never got into an accident, but doesn't mean its a good idea, right? To tape something that is electrical with an electrically conducting tape, it seems to me there should be a better reason than that it's really sticky and durable.

Someone recommended "contact paper" on a leopard gecko forum, but someone also responded with that the heat tape kept the adhesive warm and sometimes it slides. Anyone tried this?