What kind of materials should you use when constructing a reptile cage? This question was posed to me once by someone wishing to build their own reptile cage. They were particularly asking about pine and cedar as they had heard these were no good. But it did raise the question about what are the best materials.
All-glass, tubs, melamine cages, screen cages, there are many different types of housing systems for herps. Take your pick, depending on the adult size of the animal, how much room you have to spare, and how much money you are willing to spend!
Aquarium tanks: Good choice for keeping snakes under 6 feet, amphibians, turtles, and basically anything requiring a swimming pool or some humidity. If a screen top is used, there will be enough ventilation to keep a sand boa or leopard gecko or any desert animal in it. If higher humidity is needed, the screen top can be partially wrapped with Saran wrap, and the tank can be treated as a tropical garden; put soil in it and plant some plants to raise the humidity!
Viewing is unrestricted, the tank can be easily cleaned, it will not get scratched, and temperatures are easier to maintain. They are very cumbersome to move around, especially big ones, or fully-loaded ones. They need to be on a solid table or stand and if you do want to move them, the stand will need solid castors. Many lizards such as water dragons should not be kept in glass tanks, as they do not understand glass and will continuously ram into it. Tanks should not be considered for chameleons; cages are better.
Plastic/Rubbermaid tubs: The feeding trough sizes are great for turtles! You can half-fill them with water, pile rocks in a corner for the basking area, put a lilypad or two in it, and have your own indoor pond complete with turtles! For the more common sizes, the sweater boxes and shoe boxes, any non-aquatic herp can be kept in them. In fact, these are used in breeding racks and in households with too many herps to be able to have the amount of tanks/cages to keep them all in. Not good for arboreals, as they cannot climb. Perfect for use during the quarantine period prior to introducing a new animal to an established collection. These restrict viewing, and are generally limited to hatchling animals. Good to use as an emergency/isolation enclosure.
Melamine cages: Melamine is the stuff many countertops are made of. They resist moisture well, so rotting is usually not a problem. They're easily cleaned as well. Custom-made enclosures are sometimes made of melamine, and you can build furniture-quality enclosures yourself. These can be made to fit a leopard gecko or a fully grown green iguana. With a glass front, these enclosures hold humidity incredibly well.
Wood [plywood] cages: Same as for melamine, except much cheaper and easier to work with. Both enclosures, if ordered from a custom builder, can cost a great deal depending on size and material.
Screen cages/Reptariums: Excellent for anoles, chameleons, light-bodied snakes, and young water dragons. The major disadvantages are that the largest size is only 29" x 29" x 72", humidity is very difficult to keep up, and strong animals could knock them over or even move them. This is a great idea for an easily-transported cage for small animals.
MDF or craftwood: Same as for Melamine but also much cheaper. Good for use in combination cages ie Melamine base with MDF sides, back etc. It can be painted, has good thermal properties and if used in conjunction with a coating material such as Contact, will hold humidity well. Excellent to work with and has a smooth finish. You can also use thinner sheets as it retains its rigidity. Some people recommend wearing a mask when cutting or routing MDF as it can be dusty.
Pine or Cedar: Neither of these timbers should be used to construct a cage. Making the whole reptile cage from the pine or cedar has potential health problems for the animals. These woods emit aromatic hydrocarbons that can damage the health of the animals and cause various symptoms. There is probably little issue using as the woods in framing, as the wood has often dried out a lot and released much of the volatile material, or at the very least, the rate at which it is released is very slow.
It also is recommended that you do not use pine or cedar as a substrate. Pine and cedar wood shavings used as substrates have a very high surface area and so the hydrocarbons are released much more readily, making them potentially toxic, especially as the animals like to burrow and immerse themselves in their substrate material.
PVC Tubing & Mesh or Plexiglas: These materials make excellent larger cages for animals such as monitors, larger snakes, chameleons and iguanas. They do tend to lose a bit of heat but any large enclosure will require some effort to maintain a higher temperature. Lighting at the top and some at the sides (if needed) will create a sufficient heat gradient. Short of building a large frame with glass and a large door, this is the most economical way to make a larger enclosure if you do not have woodworking tools.
Overall, if you want to construct your own cages for most reptiles, you are probably better off using plywoods, melamine and MDF types of materials for most of the cage. There does not at this stage seem to be any identifiable health issues caused by these materials. Another benefit with these materials is their insulating properties. Glass is not a good material for most reptile cages (except aquatic species) as it loses heat rapidly. Many glass terrariums have an open top with no seal and this also causes a high heat loss. This means the glass cages are more expensive to heat if you use certain types of heat sources.
The front of the cage can be sliding glass, Plexiglas or a constructed glass door. A pine, oak or similar timber frame at the front will give the cage a more professional and decorative appearance.
If you paint your cage, remember to let it dry out for a minimum of 2-3 days to release as much of the volatile material from the paints. 5-7 days would be even better.
It is a good idea to make the base of a wooden reptile cage from melamine and use Silicon to seal around the edges, to prevent moisture penetrating the melamine or plywood sheeting.
There are hints and tips on applying Silicone in the "How to Build Reptile Enclosures" booklet.
A base of vinyl flooring can also be used if you are concerned about water penetration into the timbers. Be sure to seal it with Silicon and seal the holes where temperature probes are passed through.
You can also coat the MDF or plywood interiors of the cage with 'Contact', a plastic sheeting with an adhesive backing, in any colors you like, before you assemble the cage. This will remove the need to paint the cage inside, reducing fumes, and also provide a water proof seal for the MDF or plywood. Contact comes in a range of colors and is very easy to apply cut and apply.
There is much to be gained from building your own reptile cage. It is good fun and will give you, as a reptile owner, a great deal of personal satisfaction. Before you do go out and purchase a reptile, take some time to research what is the best sort of cage for your pet. You should be aware that many reptiles will grow considerably over time and you may have to build a number of cages. Good luck and enjoy.