Welcome to the forums
Hey y'all,
As far as caging material goes, I think most people will tell you that vinyl coated aluminum is the best. It is easy on the feet, can usually withstand higher heat and easy to clean. The smallest I've heard of is 1/8"x 1/8", but I've never actually seen it.
Next is aluminum. Easy to clean, sturdy. If your cham likes to climb cage walls (not all chams do) this may be an issue as toe nails could get caught/torn/infected if too small of mesh is used. (Wild caught tend to have a higher incidence of this type of problem as they tend to grip harder.) Here's the rub. . .1/8" may be big enough to prevent this, but may be too small to keep smaller insects in your cage (many families frown on this.) If your cage is outside, and you cup feed, larger gauge can be readily used. Smaller gauge is recommended while your chameleon is small, but will probably need a larger gauge as your veiled gets larger.
I think there are a few people getting creative like using a hard plastic material used for fish ponds. This sounds really promising and I'm watching to see how it holds up for my own future projects.
There are probably more, but I think the last option is nylon. This is definitely a valid choice, though it may tear easier and many a cricket has been known to chew through nylon. I personally believe that nylon is harder to really get clean when disinfecting.
Some people say glass, though you've got to have a really good reason to go with this. Some chameleons really get stressed by seeing their own reflections. On the other hand, some don't. My real issue with glass is that not only does it not allow for a gradient of heat for the cham to self regulate, there is no recirculation of air which sets you up with dealing with respiratory and ocular infections. Some chams might be able to deal with it, but I think they tend to do better without having to deal with these potential problems.
Again, which is best. Probably vinyl-coated aluminum. Besides that, I think it depends on you and the personality of your cham. (I am going to use 1/8" aluminum for Manga since I see him climbing on everything.)
As far as warming your water, you have many different options available to you:
If you are hand misting, I've seen people use tap water without issue. This of course depends on your local water treatment, or well water quality. If chlorination is your issue, if left open to the air, chlorine will usually evaporate off within a 24 hour period. (I prefer spring water for the most part.) As far as warming, you could either use a warm water bath of your mister or use a microwave like you'd do a baby's bottle. I've also seen people using coffee cup warmers (though I worry this would be a great place to grow bacteria).
If you have a misting system, (which I totally recommend) I have heard of people using an aquarium heater in their resevoir, or wrapping a heating blanket around it. (Again issues with the bacterial growth.) If you have questions about misting system's, the following web-site give comparisons of premade systems (so worth it), but also information on how to make your own.
http://www.chameleonsdish.com/hydration/wateringsystems.htm
Remember- Misting is not only for chams to drink. It is important for their eyes and their skin. Though some veileds will drink out of a bowl or glass, this does not substitute for the fluctuating change in humidity that is created by misting the enclosure. Regardless of whether your cham likes it, it still needs to happen. (You also can spray the screen above him so that he's not getting it in the face.)
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Here in the forum, you have a wonderful opportunity to ask questions and read previous postings on caging, food, lighting, supplementations,... Cham husbandry is one of the hardest hobbies out there. Do your homework now. Chams get sick really fast and die if you don't. Usually, by the time they show they are sick, they have been sick a while and it is an up hill battle to get to normal.
If you haven't done it already, I'd post a picture of your enclosure. Post foods, lights (types and wattage), supplementation, humidity, ambient temp, etc for critique. If you don't know how to care for bugs, gut it up and learn, because the quality of the bugs you give determines the health of your lizard. If you are a first time cham owner, this is how you can figure out if there is a problem before there is a problem. (Beware of the pet store employee that says he knows chameleons

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Good luck! I know you'll have a blast raising your little one like I have mine.
Matthew