hoppycalif

Niko jolted me into thinking "outside of the box" on light fixtures with this great thread: http://www.aquaticplantcentral.com/f...ter-light.html
So, I designed a cantilevered light fixture that is a "pendant" style, but on a parallelogram linkage. This will allow me to swing it up out of the way, but still have the light directed down into the tank, and changing bulbs will be relatively easy. I will use this with an open top tank, in place of my current fixture that sits on the tank with the front half hinged to lift up.

Today I started making the actual fixture body, from 1/4" MDF, a simple box, but with the front and back angled so I can use mylar on them to help direct the light that would over shoot the tank top back into the tank. I will use my current 2 X 55 watt AH Supply kit, and the down position of the fixture will put those bulbs about 4 inches above the water vs. the 2" height they now sit at.

Here are my design sketches, which should be understandable without notes, I think:




The parallel links will be made of 1/2" x 1/8" aluminum bar. There will be an electrical outlet in the wall mounted box that the links attach to, for the lights, with the power coming by way of a timer mounted below the tank.

hoppycalif

The body of the fixture is coming along well:



First cut out the two end trapezoidal pieces, making them identical by stacking two pieces and cutting them at the same time. Then cut the front and back long pieces, making sure they are the same length. I set my skilsaw to cut at an angle, using one of the end pieces as an angle gage. That left the top and bottom edge at the right angle. These four pieces are then glued together - simple butt joints. (Which is when I discovered the front and back pieces were about 3/16" wider than they should be, so I have to trim them later.) Finally, cut the top piece using the same angle setting on the skill saw for the front and back edges to match the end piece angles. This is then glued on top of the assembled four pieces, using it to square up the "box". (I let the glue dry from the first glueing before glueing the top on.) After a short drying time, I used cut off strips of the MDF to reinforce all of the inside corners, which is when the photo was taken.

CraigThor

Hope this works would love to do something like this over my 75... how will it stay in the up position?

hoppycalif

The fixture "box" is finished, other than painting. I used a router to trim the front and back pieces, and to cut ventilation slots on top, the used a random orbit sander to clean up the joints. The first picture shows it sitting on top of my existing hood, and the second is the "box" showing the ventilation slots.

hoppycalif

I'm sure it will work, since I'm always sure my ideas will work, even when they don't. It will stay up by putting a spacer block between the links on one side - the exact design of that I haven't figured out yet. Since the links will not be able to close, the fixture stays up.

I ordered the mylar for the front and back pieces, to make them reflective, to capture the light spillover and direct it to the tank, from treefish who, fortunately, had one piece left to sell. Tomorrow I will go look for the aluminum bars, and the electric outlet and junction box for the outlet - both being the smallest I can find.

Now, a question: you can see that I have a light fixture now that is the same oak material as the cabinet and the fake oak trim on the tank. This won't easily finish with an oak finish, so what is the best paint color to use? I'm vacillating between the off white of the wall and black or gray. The aluminum link bars can be left plain or finished the same color as the fixture.

newbie314

Do you go to blue color for the aluminium.
That place is great.

hoppycalif

What is "blue color"? No, I just visit Emigh's Hardware on Watt, where they have a nice selection of aluminum, both sheet and extrusions. I considered making the "box" out of aluminum sheet, just for the experience, and as an excuse to buy a pop rivet tool, but that seemed wasteful, to say the least. I knew I could make a nice one with MDF, so that's how I went, at a cost of $4 for the material.

CraigThor

Hoppy, to hold it up what about a slide bar latch like used on older inside doors/ restrooms?

Craig

niko

Hoppy,

I don't understand - when pushed "out of the way" the "hood" will end up behind the tank or what?

--Nikolay

hoppycalif

A latch like this?


That would prevent the links from collapsing in contact when the light is down in position, which is what positions it there. Or did I miss something? A "U" shaped one would do it, if I didn't lose it.