Reptile & Amphibian Forums

How much of a gap should I have between the wood bottom and the plexiglass? Could I just put a thick bead of silicone and then set the plexi on top and that would be enough of a gap?

Thanks so much, everyone on here is always a big help especially for us brainless builders who bite off more then they can chew..

Don't know exactly what you are describing but I'll assume you want to heat through acrylic? Well, it may be problematic. When you heat acrylic with any heat pad where the surrounding area is much cooler, the plastic can warp. May not be much of a big deal. I've heated acrylic boxes that way and the bottom did bow up a bit, but so what.

There are wonderful ways to heat cages these days w/o Flexwatt believe it or not. Depends on the species kept and other factors of course, but Flexwatt isn't the only way, especially when you are dealing with a single cage.

And why an acrylic bottom? Expanded PVC is available and a better choice for heating with an undercage heater, if I am understanding correctly what you are trying to accomplish.
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Mark

Im heating a wood cage that is 4x2x2 for a small boa.Im using a ceramic heat emitter and a piece of 11x24 inch flexwatt.
I dont want to cut any holes in the wood bottom so I was making a slightly raised platform to put the flexwatt under.
Plexiglass is just easiest because they sell it in town.I dont know where to get the expanded pvc stuff, I imagine home depot would have it and cut it for me??

Cut it to fit the entire bottom, put the flex under that and siliconed it in? Ive seen people use linoleum or tile but Im pretty sure they routed out a breathing space for the flex.

OK, I see what your goal is. I have opinions of course!

First, lets talk about other methods. Turns out that a radiant heat panel or an additional CHE will do the job for you, without needing Flexwatt.

What I have found using CHE's and/or radiant heat panels is that the end result is very much like Flexwatt - the snake's mass is warmed, rather than the air (although of course in a closed cage the air temp can rise due to any type of heater.)

And contrary to what many believe, bottom heat dries out an animal just as much if not more than radiant heat from above. I actually see better humidity levels using CHEs and RHPs compared to undertank heat.

So here is a suggestion: Have one CHE (like a 30 or 40 watt) on one end of the cage, and then have another (like a 60 or higher) for the other end or the middle for the main basking area. Using 2 CHEs in a large cage is better than one single ultra hot CHE. You must use a controller. If you put the probe under the higher wattage CHE, the lower wattage CHE will always be cooler. Have both CHEs plugged into the controller. I recommend any proportional controller for this - less headache.

If you still want to use Flexwatt, I recommend the expanded PVC, often called Sintra. You can get it at sign shops or order online (shipping is often high). Sign shops often have scraps or else they will order it for you. They can cut it to size too, although it is the easiest plastic to cut - easier than acrylic. You can carefully score it (use a metal straight-edge as a guide) many times with a utility knife, then bend it to break it, or you can use a saw, or just keep scoring over and over with the knife until it breaks thru.

As far as air space - overrated. Flexwatt can't get too hot if the heat is conducting to a mass, which in this case is the PVC and snake. Of course you need a temp controller. If you can, get the lower wattage Flexwatt - the 17inch wide stuff - as I think is is about 20 watts for a 17x11 piece, vs 20 Watts for the standard 11x11 stuff sold. That is nearly 1/2 the watt density for the 17inch wide Flexwatt. I think the Bean Farm has it. A bit safer than the 11 inch for enclosed areas. So, I wouldn't worry about air space when using the reduced watt density Flexwatt. Its funny that people always say to use an air space, then you look at all their racks and cages and there is negligible air space to speak of. It is one of those regurgitated pieces of advice that everyone says but almost nobody follows perfectly. PC for sure.
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Mark

I tried to do whjat you are saying,lay a bead of silicone and put plexi on top. Doesn't work. Atleast not for me. I used a 11 x 23 Ultratherm and 1/8 plexi. The plexi warped and pulled up when heated. Maybe 1/4 would work with an adhesive caulk.

ive had issues with plexi warping like mentioned and i wasnt even heating directly. my cages have doors that are made up of no more than a plexi glass pannel, and with an ambient temp differance of not even 10 degrees the inside expands alot more than the outside causing it to bow quite a bit, now im my case not a huge deal that just makes hard sometimes to put the doors back in (taking them out is easier), but i alread have changed my design for the next set of cages.... again this is just ambient air temps, i can imagine it being alot worse when heating the plexi directly
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-Stephen-

0.1 Fiance (Babe)
1.0 rotwiler/chow (Boomer)
1.0 norm corn (Jake)
1.0 col redtail boa (Switch, formally known as Dixie)
0.1 ball python (Bella)
1.1 Brazilian Rainbow Boa (Torpaz & Saphira)