Can't decide on joinery

[Scott Bell]

Hi folks,

This is my first post in this community. I'm a new woodworker, too. The final push to get me going was the project on currently working on. I’m designing a canopy for my 75 gallon aquarium.

The canopy will be able to open in a couple different ways. One way will just open the front portion of the hinged lid (for feeding time), and the second way will be able to open the whole lid up and out of the way (for maintenance).
Think of the hinged lid as kind of an “L” rotated 90 degrees clockwise. One hinge will be near the intersection of the “L”, but set a little further back, so that the piece can be opened and rested on the long part of the “L”. I’ll probably just use some kind of continuous hinge in this location.
The second hinge point will be at the end of the “L” and will lift the whole lid up on some kind of chest lid hinge. I haven’t decided on hardware for the hinges yet…
BUT, my question is… what kind of joinery would y’all suggest at the intersection of the “L”?
This lid will be opened multiple times a day, so it would have to be able to put up to some abuse. I plan on using 1/2” stock so that the whole canopy is not too heavy, and can be removed by one person in a pinch.
I’ve included a sketchup model (render) of the canopy, minus the lid…

thanks for reading!!

[Jamie Buxton]

Joinery answers usually depend on the material you're using. You mention 1/2" material, so I'm guessing you're using plywood, not solid lumber. For plywood, I generally use butt joints. I often use biscuits to help position parts during glue-up. To reinforce that short L at the front, I'd use some small triangles of plywood on the inside of the joint. The triangles would reach back to the piano hinge. Instead of just a half-inch of butt-glued joint trying to hold the L stiff, you'd then have several inches of stuff holding the L stiff -- much better.

[Jeff Bratt]

Have you worked out how both hinged pieces will move when opening them? Opening the whole top like you've described sounds a little awkward. Have you considered having the two lids be separate, the front piece hinges down in the front, and the top piece hinges at the back like you described?

Just my 2 cents... Also, make sure to use hinges that won't rust in this high moisture (+salt?) environment.

[Scott Bell]

Well, thanks for the quick responses. I appreciate it.

Yes, i had planned on using plywood. I like the idea of using the triangles to reinforce the L. I have plenty of scrap around already that could accomplish that. I had planned on using scrap to reinforce some of the corner joints of the shell already... glue block style. As far as the hinge setup, I had thought about this (and excuse the crude paint mock-up!):


So the front part would fold back onto the top of the other piece. Ideally i could rotate that front piece 270 degrees to lie flat on it's back. Ideas on a hinge that could do that? I'd probably have to move the first hinge closer to the corner then, i'd imagine. Then the back set of hinges would just fold the hole thing up, a little more than 90 degrees.
If i split the pieces to have the front fold out and down, instead of up, it would restrict my access to the tank, and the view to see what's happening. I'll definitely look for some rust resistant hinges. Probably just some stainless steel ones.

I'm open to new ideas though, so please if anyone has an idea, share.

Thanks for reading!

[Jamie Buxton]

..So the front part would fold back onto the top of the other piece. Ideally i could rotate that front piece 270 degrees to lie flat on it's back. Ideas on a hinge that could do that?...

If I understand your plan correctly, the front hinge needs to go 180 degrees, not 270.

[Jeff Bratt]

So the front part would fold back onto the top of the other piece. Ideally i could rotate that front piece 270 degrees to lie flat on it's back.

I'm not quite sure what your 2nd drawing shows...
Your piano hinge will only rotate 180 deg. The bare hinge can rotate further - but once you attach it to pieces of wood, rotation will be limited to 180 deg.

[Scott Bell]

If I understand your plan correctly, the front hinge needs to go 180 degrees, not 270.

I'm not quite sure what your 2nd drawing shows...
Your piano hinge will only rotate 180 deg. The bare hinge can rotate further - but once you attach it to pieces of wood, rotation will be limited to 180 deg.

Yeah, y'all are right. In the drawing i'd only be able to rotate it 180 degrees. I was just dreaming of a way that i could install a hinge to rotate that piece 270.

[Jeff Bratt]

There are hinges that can move 270 deg - euro-style door hinges, and some for entertainment center "flipper" doors. It looks like most are made for 3/4" material - maybe you could find some designed for 1/2". And some come in brass, maybe stainless too... Something like these could work if your front door piece is flat, not L-shaped.
http://www.rockler.com/product.cfm?page=259
http://www.hardwaresource.com/hinges...abinet+Hinges/