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Discussion Starter · #1 ·
Niko jolted me into thinking "outside of the box" on light fixtures with this great thread: http://www.aquaticplantcentral.com/...ltra-efficient-inexpensive-monster-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.
 

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Discussion Starter · #2 ·
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.
 

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Discussion Starter · #4 ·
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.
 

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Discussion Starter · #5 ·
Hope this works would love to do something like this over my 75... how will it stay in the up position?
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.
 

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Discussion Starter · #7 ·
Do you go to blue color for the aluminium.
That place is great.
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.
 

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Hoppy,

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

--Nikolay
 

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Discussion Starter · #10 ·
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.
 

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Discussion Starter · #12 ·
Hoppy,

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

--Nikolay
It ends up against the wall, about 10 inches above the top of the tank, giving great access to the tank for maintenance.

I ended up with this design after trying to use drawer slides to make it easy to shove the fixture back from above the tank. But, I only have 4 inches clearance between the tank and the wall, so I couldn't make it go far enough back. Then I decided to also hinge it so it would slide back and then tilt up. But, that left the light shining in my face. Then I remembered the parallelogram linkage, and spent a couple of days playing with that before I understood how to optimize it. Now I think I have what I wanted - good access, nothing above the light to see, easy to change bulbs, an open tank top, and no cooling fan needed. It is a pretty cheap thing to try out, since I will use my existing AH Supply light kit.
 

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Discussion Starter · #13 · (Edited)

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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.
Sorry should have been blue collar. Has lots of misc. stuff. Like already cut plexi-glass. You don't have to buy a whole sheet. Take a long strip.
I got aircraft aluminum piece for making my brake bracket on my electric scooter.
 

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Discussion Starter · #16 ·
I found that Blue Collar place in the phone book, but I already visited Emigh Hardware. They had little or no aluminum, but lots of iron bars. I quickly found out that aluminum bars wouldn't be strong enough, since the iron was just about the right strength. So I bought a 4 foot piece of 1/8" by 1/2" weldable steel bar. That will make the 4 parallelogram links.

My wife objected to my MDF fixture box, so she "persuaded" me to cover it with oak veneer. That will likely be the job for tomorrow. I'm up to $29 for materials now, but very little else to buy.
 

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Discussion Starter · #17 ·
I made the links and the wall mount board, and assembled it for the first time today:


The first lesson I learned is that it will take two barrel bolts to lock this in the "UP" position. With only one it twists very badly, which is obvious when I look at it. But, the concept seems to work just fine. I can't photograph it in the up position now because I don't have enough hands to hold it up and take the photo too. Tomorrow I will mount this on a piece of scrap plywood to simulate the wall, then install the barrel bolts. My costs are now up by another $9, plus $15 for contact cement for the veneer and a can of Rustoleum paint for the links.
 

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I made the links and the wall mount board, and assembled it for the first time today:


The first lesson I learned is that it will take two barrel bolts to lock this in the "UP" position. With only one it twists very badly, which is obvious when I look at it. But, the concept seems to work just fine. I can't photograph it in the up position now because I don't have enough hands to hold it up and take the photo too. Tomorrow I will mount this on a piece of scrap plywood to simulate the wall, then install the barrel bolts. My costs are now up by another $9, plus $15 for contact cement for the veneer and a can of Rustoleum paint for the links.
Looking good, would like something like this for my 75. what size tank is this going on? Mine is 4'

Craig
 

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Hoppy it looks good. :D If there were something you could use other than that heavy MDF. I was gonna suggest the faux wood grain finish to match your tank trim. You would use a graining tool and 2 tone stain/paint. Sounds like you have it solved with veneer.
 

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Discussion Starter · #20 ·
Looking good, would like something like this for my 75. what size tank is this going on? Mine is 4'

Craig
My tank is a 45 gallon tank, only 30" wide (actually closer to 29"). The wider the tank the harder it will be for the linkage not to twist. If I were going to try it on a 48" wide tank I think I would put more room between the two links on each side, which requires the tank be further from the wall, if you want to raise it a significant amount. And, I would use 1" x 1/8" steel bar for the links, for more stiffness. Then I think you could raise the fixture with one hand, push the barrel bolt in place to lock one side, then switch hands and push it in on the other side to lock it. Since raising it would be for major maintenance only, it can be a bit awkward and not be a problem. Or, two people could easily raise it and lock it up.

Before I am willing to say I like this, I want to get it finished and installed. So, the "jury is still out".
 
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