So I had a go at my first 2D curve snap fit design. Once complete I exported the curve models to a dfx file to be laser cut from 2mm plywood.

The DFX file is available for download free - linked above.

Surprisingly it worked out perfect first time which I wasn't expecting.

So using regular wood glue I assembled the pieces and used fibreglass tape to hold everything in position until the glue had cured.

I first gave the whole hood a primer coat before attacking it with black gloss. Once the gloss had 24 hours to fully dry out I sealed the inside of the hood and lid with fibreglass resin, at the same time I placed a plastic tab in all 4 corners pinned in with fibreglass cloth sealed as one. These tabs will slot into the tank and hold it in place.

Next the lid needed hinged.

The aquarium light I'm using is a water proof IP56 light from a Aquaone hood. I needed to cut out a hole exactly for the light to pull out of the back to replace bulbs in the future.

The hinge screws I just used hot glue over and put a blob on the ends. The turtles cannot possibly reach these but "just in case" they cannot cut themselves.

The plastic light cover I hot glued in place then when set used hot glue again to seal it. Now the light is isolated from internal hood moisture.

With the hood in place and the light offset it provides a bright and dark side of the tank for the turtles pending their mood. The hood provides an additional 15cm / 6 inches of height at the back meaning I can gradually raise the water level to provide more swimming area and still have plenty of room for the turtles to get out of the water on the platforms.

With the lid on the hood closed all the light is refracted into the tank itself one way or another but with the light off the tank is much darker than normal which is beneficial to the turtles rest pattern.