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Plant Tank Setup Project
Do It Yourself Canopy

by Doug Valverde <75051.160/>
Date: 21 Feb 96

This portion deals with how to build your own canopy. There are a million and one variation on this so certainly you can do things different if you desire. This is the eight canopy I've built and each one gets better and better. At the same time I upload this I will be uploading another file on canopy building that I wrote about a year ago and never uploaded. The earlier method is truthfully easier, this one IMO has a more smooth professional look.

Often if you make a mistake here you can simply turn the wood over and put the mistake on the inside of the canopy. The fish won't care. <g>

But on with the story.....

There are a few options on how to top your tank. In another file I'll get into specific lights and types, but before you build a hood or canopy you need to have a good idea what you want. Fluorescent for example run cooler and thus require less headroom then do the hotter burning MH bulbs. In my case I intend to ultimately end up with 4 VHO bulbs and two MH bulbs, so I have to plan for room, cooling, and headroom. MH needs to be roughly 12 inches above the water and in a position it cannot be sprayed with water.

The options are suspended lights, wall mounted lights, a hood or box enclosure, and a full canopy. I'll skip all but the last. Suspended lights usually come in prebuilt pendants, or you can build a simple box to hold them. Likewise I hope all of you can figure out how to make a wood box and simply lay it on your tank. So I will concentrate on building a canopy.

Considering this the sides of my canopy will be 12 inches tall. On canopies I have built in the past I have used 6 inches and 8 inches to accommodate fluorescent bulbs.

Next you need to consider the top. How do you want it to open. I like mine to open in two different places. One a smaller opening to accommodate feeding, and gravel and tank cleaning, as well as plant maintenance. Or in other words I need an opening big enough to fit my arm through and have some room to move. The second opening is so that I can get in and change bulbs without having to take the top off. I'm lazy and would rather design a hood that is easy for me to work with, so I think a bit of thought as to how to accomplish that makes life easier.

I am not a cabinet maker, nor am I good at working with wood. In fact my only credentials for his type project is I ain't paying for commercial units, and I am patient. I have built 3 hoods (by this I mean a box almost that contains lights and sits on the tank, or is suspended) and five canopies so far. If you wonder and look at each of them in my house you can tell the progression from first to last, with each getting a little more polished.

You will almost have to have some tools. A screwdriver (drill or cordless drill/screwdriver being better.) A keyhole saw (jigsaw being easier). A mitre saw (lot of table mounted options if you want to spend the money). You can use screws or dowel pins to hold it all together. This time I am going to try dowel pins because I do not want screw holds to show. If you would rather try screws, which is easier, you will need to decide you really like the look the screws have when they show, or you will need to countersink them and fill them up with wood filler, wood putty, wood caps, or something similar. I've never been able to get it to where close observation didn't immediately reveal the screws so that is the reason I'm trying dowel pins. Ain't never used them so we shall see. I did go down and spend $18.00 to get a jig to help align the holes for these.

You also need to consider how you want to finish the canopy. I have no choice. My wife demands stain and varnish. As a result I need to get a very good grade of lumber. Paint, formica, or tiled finishes require lower grades of wood and with the latter two plywood is acceptable as long as it is for outdoor use. Never tried formica, but I think I will give it a shot next time.

I did just get back from the lumber store with my wood for this. I used an extremely scientific way to decide what I wanted. I live in a rural area so yall city folks may have better choices. Previously I have used poplar, which I liked because it is so easy to work with. Also used white pine which was fine as well. But this time I am using Aspen, due entirely to my new scientific method. I could have used pine, but that would have meant going to the outside warehouse and is a big hassle so it was excluded. That narrowed my choices down to cabinet quality woods that the store has inside. My choices were mahogany, oak, aspen, or something else I can't remember at the moment. Mahogany was expensive and they did not have the lengths I needed. Scratch mahogany. Oak was more reasonable, but they did not have 1" X 12" X 6' or 8' so it was excluded. Same for the other wood I can't remember. So I decided to use Aspen.

So I bought 3 1" X 12" X 8' boards, and one 1" X 16" X 5' board. To fit on my tank using wood of this thickness the front and back boards must be 52 inches, and the side boards 26 inches. This is to allow clearance around the trim. I want the top to overhang the sides by one inch all the way around so that gives me a top width of 28 inches. This will be two pieces so one will be out of the 1" X 12" boards, and one part 1" X 16". The larger piece will contain my lights. As such it will be a box in a box. The inside will have wood sides and a plexiglass bottom so the light can shine through. It will also be mounted with two muffin fans and will be weatherstripped to reduce moisture.

So far here are my costs:

(3) 1" X 12" X 8' Aspen Boards $19.00 each $57.00 total
(1) 1" X 16" X 5' Aspen Board $19.00 each $19.00 total.
(3) Full Offset Series 4000 Hidden Hinges $17.00 Pair $34.00 total.
(3) Brass Cabinet Hinges $4.99 Pair $9.98 total.

All other miscellaneous wood parts I will use I already have, and are scraps from other projects. As I actually cut and assemble the hood I will mention them and what I am using, but as they are interior pieces and can't be seen they are very inexpensive.

(1) Dowel jig (include dowel pins) $18.00
(1) Mitre Box (for large pieces of wood) $25.00 **You don't need these, but it makes it easier for me to get the razor straight cuts I want with it, and I can't talk my wife into that nice $500 table saw I want. <g>
(1) 35mm Drill Bit $19.00 **Used only with hidden hinges, otherwise is not necessary.
(1) 3/32" drill bit. For starting screws N/A I already had.

Other tools I already have, so the above is all I had to buy. I will be buying a piece of high temp glass in the near future, but will not do so until I order my MH bulbs, and as it does not affect cabinet assembly I'll skip it for this files purpose.

First thing is to determine dimensions. You need to know the thickness of your wood. I use 1" thick wood, which is really 3/4 inches. You have to have two sides so you must add 3/4 inch twice, or 1 1/2 inches to the length of the tank. The length of the tank must be measured including the trim that goes around the top of the tank. To this measurement at the 1 1/2 inches previously mentioned (remember this figure is dependent on the wood you use and what it's actual thickness measures.), and then add an additional 1 inch. This is to allow for the wood swelling, and for minor measurement errors.

The sides are easier. It is the width of your tank, including trim, plus 1 inch again to allow for swelling.

As an example my 120 gallon tank:

The length of the tank, including trim is 48 1/2 inches. So I add 1 1/2 inches to accommodate the width of the wood on both side pieces. That gives me 50 inches. To that I add 1 inch, so the total length of the front and back pieces is 51 inches.

The sides are simply 24 1/2 plus 1 inch for a total of 25 1/2 inches. Both pieces will be cut using a metre box so the cuts are as square as possible. The particular metre box I have is somewhat of a misnomer, it is not a box, but rather a mount that clamps on the wood and an arm that firmly holds a metre saw in place. This way I an not limited as to the width of the wood I want to cut. Many metre boxes can only accommodate wood up to 4 inches.

You can simply use a skill saw or jigsaw or just a handsaw to cut the pieces, and it will work fine as that is what I have done on the rest of the canopies I have built. This one I just want to look really professional when I am finished and I know I can get more precise cuts this way.

After I complete the cuts I will attempt ot figure out how to use dowel rods to fasten the sides to each other. In each corner I will also use a 2 X 2 cut 10 inches long. These pieces will accomplish a couple of things. It will brace the corners making the entire assembly much more rigid, and they also will allow the hood to sit on the top of the tank with 2 inches covering up the trim on the tank.

Got the lumber, 1 X 12 Aspen cut to the appropriate lengths. For this purpose I used a metre box and back saw. (More on this in one second.) This particular box has an arm that holds a back saw, or a regular hand saw, but the wood does not have to fit into a box so you can accurately cut larger boards. This was the first time I tried this approach, but what I wanted was a more square cut then I had been able to do using hand held power tools.

This approach did work well, although was a pain. A back saw is designed to make nice smooth cuts, and this it did well. Unfortunately it is slow and does not make cuts as quick as a regular saw.

However, I did get all the wood cut and the cuts were neat, clean, and square. So far so good.

Next as I have mentioned I decided to use wooden dowel pits to fit the canopy parts together so I would not have to concern myself with screws or anything else showing. So for the first time I set up a jig I bought especially made for this purpose, and away I went. First joint was perfect. So on to the next joint, and this is where I made mistake number 1 of 3. I moved over to another corner, set up the jig, started drilling my holes for the dowel pins. Got three out of the five holes I am using in each corner drilled, when I realized I drilled the wood on the wrong dang side. No big deal, messed up one piece. So here comes mistake number two.

So I decided to cut another piece and get on with it. But you know how I mentioned above the back saw was kinda slow. Well the metre box said it would work with a regular hand saw so I decided to try it. Well it did cut quickly, and I am sure had I been cutting a smaller board it would have been fine, but as is it was not stiff enough and when I got through the cut was curved, not square. So scratch another piece of wood. Tried again and finally got it right, but not before I used a piece of wood that was slated for the canopy top.

Mistake 3 was minimal. When you use a dowel pin you have to drill matching holes on each piece of wood. On the board which will be the back of the tank I drilled one hole too deep and it went through the board. As it is the back and will never be seen, it was not major, but I mention it only so if some of you decided to try this method you will be forewarned.

I finally did get everything drilled correctly and fitted the lower portion of the canopy together. Perfect! Corners are neat and square and the wood exactly fit together.

In the meantime I planned everything I wanted to do, and how I was going to accomplish it. I want each corner braced, so I bought 1 X 1 pieces of wood. Each will be cut exactly 9.25 inches. This will be fitted to the top of each corner. These then will hold the corners rigid and at the same time provide a stop for the canopy so when I slip it over the tank it will stop with two inches overhanging the tank, completely covering the trim of the tank.

I also had to consider I plan on adding MH bulbs, so in preparation I want a subcabinet (think I just made that word up) to hold the lighting. I also still wanted to add some supplemental strength and rigidity to the canopy. So I bought a 1 X 8 piece of wood which will run lengthwise inside the canopy, 14.5 inches from the back. When I add the MH lights I will drop in a piece of glass into this subcabinet to protect the bulbs from any type of spray. For now it is just going into place. My top will be two pieces. The back piece is 16 inches wide (really 15.25). This piece will use hidden hinges (them sucker's ain't cheap. $17.00 for two hinges, and then I had to buy an $19.00 drill bit to mount them.) These are self closing hinges and will pull the back of the canopy down tight when it is not open. Purpose is to let me have free and easy access to the lights for changing. Normally this portion of the hood will be closed.

The front of this portion will rest on the 1 X 8 piece that runs the length of the interior of the canopy.

The front opening of the top will be 11.25 inches wide (1 X 12 lumber). It will also have cabinet hinges and will rest on the crosspiece. This is the portion of the hood that will normally open for feeding and cleaning. However, should I ever need it I can raise both front and back pieces and have total and free access to the tank, without removing the canopy. Same with changing bulbs, a problem all of my previous canopies share. Once every six months I got to take the entire canopy off to redo the lights. Not this time.

For the canopy top I will use a 1" X 12", and a 1 X 16" board for the two pieces. Each is cut 1 inch longer then the front pieces so they will overhang 1/2 inch on each side. They will also overhang the front by about 3/4 inches so I can open it simply by lifting up on this lip.

As I've mentioned I have build several of these before, with each one getting better then the one before. If you will allow me, I'll admit my past mistakes and tell you how to avoid them.

One of the mistakes I made a long time ago was to cut the wood where the sides extended out to where the front is, and the front fit in between the sides. This left the joint in front of the tank. Big mistake. With the high lighting we often used you would get these nice bright beams of light in your face when you looked at the tank. Not good. <g> So be sure your joints are on the side, not on the front. Looks better too.

So now for the biggest trick of them all. Sand Paper! In previous canopies I have bought all different kinds of wood, including some pretty expensive woods. The better quality wood had a nice smooth surface, so I figured sanding was not important. WRONG! If you are going to paint, or stain and varnish the wood, you must must must sand it first, regardless of how smooth the wood feels. Otherwise you will be forced to put 8 million coats to get a smooth finish. For sanding I start with 100 grit paper and end up with 220 grit, with 150 or 180 grit in the middle. The better you sand the fewer coats you will need and the better your finish will be. This includes the inside you will never see, but for different reasons. (See Note at end of page).

So let's talk inside for a moment. Heck you can't see it when the top is closed, so what's the big deal? One you want a highly reflective You've got a few choices on the interior and what you use is up to you, but do not neglect this part. If you leave it bare wood you will have problems with warping and swelling. So no matter what surface I want to end up with I always prime and paint the interior. I use a high quality exterior epoxy paint. Normally oil based, but this time I've given high gloss epoxy latex paint a shot, mainly because of clean up time. I've used this same type paint on my house in Tampa (when I lived there) and it worked well. Hopefully it will work well for this purpose too. But having said that until I am sure I still recommend oil based paint as it has stood up to the test of time. So your first course of action is to sand. Hand sanding works just fine. In my old age I've gotten lazy, and as I am redoing this house I have detail sanders, belt sanders, orbital sanders, and rotary sanders hanging around. So first I carefully sand what will be the interior with the grits mentioned above. Once I have a silky smooth surface, it's time to paint. First a coat of primer. Then at a minimum three coats of epoxy paint. I always use at least three and sometimes four to get a real slick surface. A lot will depend on the paint you use. Best I can tell you there is very carefully follow th wood, not wood to paint, or paint to paint.)

After the interior has dried and cured you can now sand the outside. First sand any and all drips you may have as a result of painting the interior. Next sand the entire exterior. If you chose to use varnish you will need an exceptionally smooth finish. I started with 100 grit, then 150 grit, then finally 240 grit before varnishing. After the 240 grit, as I am using water based varnish, I used a wet rag to moisten the wood and let it dry. Then I resanded again with 240 grit sandpaper.

I should mention that the canopy is not assembled at the moment, but is in pieces. Reason is it let's me get corners easier. I'm using a quick drying water based satin finish polyurethane. Nice thing about water based finishes is their quick drying time. This particular one dries to recoat in 45 minutes. That allows me to do all the varnish in one day. Not to mention everything is water clean up.

In between each coat I'll sand with a 400 grit sandpaper, and will use six coats total. After the final coat polish with a 600 grit sandpaper.

The varnish takes three days to completely cure so it will not go on the tank until then. In the meantime tonight I'll put hinges on. Soon as it is cured I'll toss my VHO lights on it. Later I will be adding more lights, but that is a footnote and does not affect assembly or use.

I used a jig saw to cut the back panel for my overflows and incoming water. Tomorrow I'll also drill several small holes in a circle to provide a vent for my fan. To make that look even I'm going to use a compass to lightly pencil in several concentric circles, the largest circle being the diameter of my muffin fan. I'll then use a protractor to draw intersecting lines so it will look neat. Not real sure why I'm bothering as it will be on the back of the canopy, and unless someone manages to squeeze their head in the two or three inches of clearance between my wall and the back of the canopy they won't see it anyway.

The hidden hinges were much easier then I thought to install. I'm not sure I'd recommend the hidden hinges where costs are a big factor. For the length and weight of the canopy top I needed three hinges. Naturally they come two to a pack, and each pack costs $17.00, or $34.00 total for the hinges, then I also had to buy 35mm drill bit to drill for the cup these type of hinges use. The drill cost $19.00. For me it was worth it. I've built several canopies now and will undoubtedly build more in the future. I wanted the back portion of the canopy to be hinged while looking like it was fixed. Also, to me, the directions were a little awkward. What I finally did was measur 1/4 inch bite on the cabinet), to attach these to the corners where they will come 2" from the bottom. These serve two purposes. One to make the hood more rigid, and two to become the stop for the canopy. Thus the canopy will overhang the tank by 2 inches, completely covering up the trim, but still giving me 9 1/4 inches of room for my lights.

The final things I will do will be to add more lights and more fans, but this is not material to the actual building of the canopy.

The main thing on building this type of canopy is to measure carefully. Paint can be stripped and repainted. But if the wood is too short you cannot stretch it back to shape. I've built complete canopies in under three hours, excluding varnish and painting, so it need not take you forever. This one took me longer then most, mainly because of the dowel pins. Being unfamiliar with their use I was very slow and careful. If you have the patience though I highly recommend these. You end up with nice tight corners and no screwholes.

Best thing is if you take your time and be patient you end up with a cabinet that looks as good as those costing hundreds of dollars more, but you get the satisfaction of having built it yourself. Plus with a little thought you can design it to be far easier to work with then anything you will buy.

As always, if you have any problems send email to me and I will do my best to provide the answers.

Note on Sanding

>> #: 581350 S13/Aquatic Plants
    22-Jan-96  04:32:12
Fm: Carl Gustafson 73707,41
To: Doug Valverde/Staff 75051,160

>> If you are going to paint, or stain and varnish the wood, you must must
must sand it first, regardless of how smooth the wood feels. Otherwise you
will be forced to put 8 million coats to get a smooth finish. <<

One trick when using a water-based finish on your project -- after the final
sanding, wet the wood, and let it dry. This will raise any grain that would
absorb water from the finish and swell. Once dry, sand again with the final
grit, and you will get a much smoother finish.


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This page was last updated 29 October 1998