how can I build a 20 gallon or bigger cage

for what? Leopard Geckos? I would take a look around and see if you can find some pics of others enclosures and see what kind of things you think you want to include and then from there ask more specific questions...

__________________

Building an enclosure is going to be guided by what you intend to keep in it. If it is for a tropical critter, the enclosure will need to be moisture-proof. If it's for a desert critter, that may not be a factor. A ground dweller will need a completely different set-up from an arboreal reptile.

What do you intend to put in it?

at 20 gallons, it may be easier (and cheaper) to just buy a tank ready made.

__________________
My name is Liz
Do what's best for the animal, not what's best for you.

i have a leopard gecko that is about a year and six months and I already have a 10 gallon cage, also the gecko is about 7-8 inches long and he is starting to look cramped in there, so I was whating to know how could I make a 20 gallon cage for it? i wasn't really lookin to do anything fansy with it

then you could go with repti-carpet for the floor, water dish, moist hide, food dish?, and somethin for it to climb on (nothing to steep).

__________________

ah, we are talking about the stuff IN the tank? not the tank itself?

__________________
My name is Liz
Do what's best for the animal, not what's best for you.

i am talking about the tank its self and my other question is my leo has something that looks like sand grains right on his mouth (not in is mouth or outside his mouth, right between) and I was wondering if that is a problem

seriously, i would just buy a 20 gallon tank. or if you want a bigger one and can't afford it, try finding a used one on craigs list or something. I find used ones there super cheap.

Any particular reason you want to build one instead of buy one?

__________________
My name is Liz
Do what's best for the animal, not what's best for you.

why don't you just buy a 2 gallon tank.. It is alot easier then building one