Materials:
1 x 2 (for top section) Length dependent upon tank size
1 x 3 (for side section/frame for non-secured lids for use with most lizards) Length dependent upon tank size
1 x 4 (for side section/frame for secured lids for use with snakes) Length dependent upon tank size
* You want the 1 x 2s & 1 x 3s (or 1 x 4s) to be as straight as you can get, no bows or curves in any direction.
1/8-inch Plexiglass
Window Screen
½-inch hardware cloth (optional – used for reinforcing strength of window screen. Recommended for use with snakes)
½-inch Wire Staples/Nails (small fence-type staples/nails)
1 ¼-inch finish nails (I used 3D-bright finish nails) Aprox. 50 – 60 nails
1 ¼-inch screws (wood or drywall) Aprox. 8
3/8-inch x 1 ½-inch nylon coarse thread hex bolt - Quantity: 2
One drill bit & tap set for 3/8” – 16nc threads (3/8”-16nc tap and drill bit #0)
Small “T” brackets or “L” brackets - Quantity: 2
Wood Glue

This particular top is for a standard 55-gallon tank but I’ll try to avoid confusion by not mentioning particular measurements. Simply measure your own and go from there. I recommend leaving the trim pieces on the tank for use in securing the lid as mentioned in the instructions below.

Side Frame:
We’ll start with the side frame, the frame that goes around the sides of the tank.

1. Measure the length of your tank and add 1/16-inch. Cut two 1 x 3s (or 1 x 4s) this size. Example: If the length of the tank measures 48 inches, cut two 1 x 3s at 48 1/16 inches long.
2. Measure the width of your tank and add 1/16-inch, PLUS, two times the thickness of your 1 x 3s (or 1 x 4s), which should be aprox. ¾”. Cut two 1 x 3s (or 1 x 4s) this size. Example: Tank width measures 11 inches. Add 1/16-inch = 11 1/16 inches. Thickness of 1 x 3 is ¾-inch. ¾-inch x 2 = 1 ½ inches. Total length of 1 x 3 would be 12 9/16 inches.
3. Glue & nail the side frame together, keeping the boards as straight and square as possible. Test-fit it before the glue sets up so you can flex the boards if needed in order for the frame to fit on the tank.

Top Frame:
Use the dimensions of the side frame you just made instead of the dimensions of the tank itself, this way the outer edges of the top section will be flush with the outer edges of the side section/frame.

1. Cut two 1 x 2s the full length of the side frame.
2. Cut three 1 x 2s the width of the side frame, MINUS 3 inches (two times the width of your 1 x 2s). This allows the width of the top section to sit within the two lengths of the top section, offsetting the joints of the side frame.
3. Determine the size of the screened area you need to rest your dome(s) on top of. For instance - for this particular top I used an 8-inch dome so I made the screened area approximately 9 inches long and the width of the 55-gallon tank, minus the widths of the 1 x 2s, fell close enough to the same size. If your cage is wider than 12 inches you might want to reduce the screened area by adding wider boards or more boards to the width of the screened area.
4. Cut a 1/8 – 3/16-inch wide groove (typical thickness of a circular saw blade) ½ inch deep down the center of the thickness of the two 1 x 2 lengths. Due to the radius of the saw blade it was necessary for me to cut my groove from point “B” to just past point “A” to ensure that the plexiglass would seat properly within all four grooves. Putty over-cuts as needed.
5. Cut another 1/8 – 3/16-inch wide groove, ½ inch deep, into two of the 1 x 2s that were cut for the width of the top section. You can cut this groove from one end to the other; both ends will not be exposed.
6. Secure pieces 1 – 4 to the side frame with both wood glue & finish nails. Place the very last piece in position while securing the others in order to ensure a good fit, however, don’t secure it until after you install the plexiglass in the grooves. You’ll need the “T” brackets or “L” brackets to secure piece #4 to both of the length pieces 1 & 3. Secure from the underside of the tank top so it’s not visible.
7. Measure the distance between pieces 1 & 3 and then add ½ inch. This is the width you need your plexiglass to be. This allows for approximately ¼-inch play on both sides of the plexiglass and can be helpful if things aren’t exactly square.
8. Set the final, unsecured piece of the top section in place and determine the length of the plexiglass needed. Add 1/2 inch, just as in step 7.
9. If you’ve never cut plexiglass before I suggest letting the DIY store you purchase it from cut it for you. It’s worth every penny of it. If you want to tackle it yourself I’ve had better results from scoring it several times, using a straight edge and utility knife. Lay the scored line along a good straight edge and snap it. This can be tricky when working with long pieces. Having someone hold the main part of the plexiglass and another do the snapping helps.

   * Be careful when scoring plexiglass. It’s easy to put too much weight on the utility knife and moving too fast, causing it to jump over the edge of the straight edge and slicing thru a finger or two. I laid the top of my index finger wide open the first time I tried it.

10. Install the ½ inch hardware cloth to the underside and then stretch & staple the window screen over it to reduce nose rub injuries on snakes and some lizards.

11. Drill small vent holes in one end of the plexiglass. When drilling plexiglass, it will melt or crack if you’re not careful. Drill the holes in small steps, applying just a little bit of pressure but not forcing the drill bit thru. Remove burrs from the holes with a utility knife.

12. If you want a secured lid mark point “E” as shown, in the center of the width and ½ inch below the bottom of the tank’s trim that goes around the top.

13. When drilling holes for taps the feed rate (drill pressure) and speed can greatly affect how loose or tight the threads in the wood will be. By the same token, not holding the drill straight, at a perpendicular angle, can also affect hole/thread size. It’s better to drill in steps instead of trying to drill the hole the final size in one shot. The hole will be larger, possibly too large for the bolt, if drilled in one step. I suggest reading up on “drilling and tapping wood” with a Google search before attempting this. Drill & tap your hole for the nylon bolt and repeat on the other end of your new top.

    

Sand it, stain it, coat it, or whatever you want to do to it. Just remember to keep VOCs in mind when choosing what to do to protect it. Kingsnake.com’s “Cage & Habitat” forum has many posts about wood treatment.

There are several modifications you can do to have a more appealing or professional-looking top. One thing is to miter all corners. A little putty here & there can make a difference, too. As you can tell I didn't put forth a whole lot of effort in this top since it was just a temporary situation that I needed it for. For those of you with concerns for the well-being of the Burmese Python pictured in the tank, it was only temporary, but I appreciate your concern for it.

Have fun!
HappyHillbilly
(Mike)

I used 1 x 3s instead of 1 x 2s for the end pieces of the side frame to allow more room to install the nylon bolts for securing the top to the tank. Follow the instructions above & make the neccessary modifications to make this top. I'll line out the procedures for installing the nylon bolts.

1. Mark the end pieces for the location of the center of the hole to be drilled as shown in the photo below. Be sure to allow for 1/2 the diameter of the final hole size, making sure that once the nylon bolt is installed it will be just slightly below the bottom of the trim that goes around the top of the aquarium.

   Example: The trim on my tank was 1 1/4 inch high (or wide). I measured 1 1/4 inch down from where the top sits on my tank and then added half of the diameter of the 3/8-inch nylon bolt, which was 3/16 of an inch. I then added another 1/8-inch to make sure I stayed below the trim.

   

2. Drill a pilot hole. - When preparing to tap threads you should drill your holes in increments and not try to drill just one hole and then tap it. This keeps from making the hole too big or small for the tap.I only drilled one pilot hole (aproximately 3/16-inch in diameter) because I wanted my threads to be a little loose so I could hand-tighten the nylon bolts. I strongly suggest practicing drilling & tapping a scrap piece of the same size & type of wood you're using for the top. You can slightly overbore the final hole by moving the drill bit around a little while moving the the bit in and out of the wood. Definitely practice this so you can see how tight or loose you want the threads to be.

   

3. With soft wood you can just go ahead and drill the final hole size now. For a 3/8 x 16 coarse thread bolt the final drill bit size is a #0 drill bit. Drill your final hole and then tap the threads. They make a tap tool for use with taps but I couldn't find mine. As soft as pine is you can use a wrench like I did in the photo, just be sure to keep the tap straight when getting it started.

   

4. Install the nylon bolts. If needed, you can run the #0 drill bit through the holes a few times, slightly moving it in a circular motion to enlarge the hole & reduce the tightness of the threads. You need to keep the drill/drill bit straight when doing this or else it will just wallow out one end of the hole.

Catch ya later!