Making an Acrylic Aquarium
Types of acrylic: There are 3 types that are of concern to us: 1) Extruded All come in clear as well as tinted varieties. Clear Cell Cast acrylic is the type most suitable for aquarium building. It is also more expensive than the other varieties. You can use extruded for smaller items like HOB items. The standard sheet size available with most dealers is 8' x 4'. Sometimes you may find a 10' x 5' sheet, Clear acrylic sheets are of different thickness: 1/8th inch, ¼, 3/8, and ½ ". The thickness required is determined by the height of the proposed aquarium. As a general rule tanks up to 12" high can be made with ¼" acrylic; up to 18" with 3/8" and up to 24" with ½". The huge public aquarium windows are made with specially laminated sheets up to 4" thickness each. Length and width do not affect this calculation. Of course practically speaking the ¼" acrylic is more flexible so your cross supports must be spaced closer together and there have to more of them to prevent bowing in very long aquariums. If you can pick up a couple of pieces of acrylic from a dealer to practice on you will be able to perfect the technique before working on the main tank.
This is a new piece of acrylic with its backing paper
Backing paper being peeled off
The backing paper is there to prevent scratches. It is better to just peel enough off to expose the edges for joining. Once you have made the tank you can peel it all off. The edges should now be prepared. They may have ridges from cutting or minor fibers which can easily be removed by drawing the blunt edge of a hacksaw blade over the edge in one direction a couple of times, and then gently sanding the edge, thus:
Removing acrylic splinters by running a hack-saw across surface
Smoothing acryclic edges by lightly sanding
Unprepared edge
Prepared edge
Do not sandpaper so much that the edge becomes rounded -that will give you a weak joint later. Factory cut edges are the best,. So when you get your acrylic and are marking out the cuts plan your base in the center so the sides will have one rough edge towards the inside from where the base was cut, and one good edge towards the outside which was factory routered. This factory edge will form the joint with the base. Like wise for the two sides which will form the width-use the good factory cut sides to sit on the base. Of course if you get your acrylic cut at a professional facility you won't need to worry because all the edges will be superb. (Generally sign board makers have the equipment to cut large thick acrylic sheets).
Try and get some scrap acrylic and practice the solvent application technique like this:
Place the base piece flat on equally sized wooden planks. The edges to be joined should not be in contact with any surface otherwise when the solvent melts the acrylic it will weld it tightly to whatever surface that the acrylic is in contact with and which will never come off!
Another view
If you are not careful here your whole tank can be marred by a nasty pattern.This was a solvent spill.
Note how a solvent spill has ruined the surface appearance of the acrylic
And this a piece of paper - got incorporated into the acrylic!
Note paper inadvertently fused with the acrylic
. Now get some 5 ml syringes. They are the most comfortable to hold.. Needles should be 18 G , otherwise they will get clogged. Of course there is nothing better than all glass syringes of the 'Glass Van' brand, if you can get them any more, that is. Hypodermic needles are beveled and the beveled edge must be facing away from you and turned into the joint where you are applying the solvent. This is the edge:
Beveled edge of needle MUST be facing
This is to get direct flow into the joint and will prevent the solvent fro spurting on
to other areas. Once you have taken up the 5 ml of chloroform in your syringe place the
needle tip against the edge at the end further most from you and draw the needle back
towards yourself to end at the edge nearest you while applying gentle steady pressure on
the plunger. A thin stream of solvent will be ejected into the joint and you will see it
being immediately sucked into the joint by capillary action. This is called solvent
welding. Do not move the two pieces now, and do not apply more solvent.
Solvent welding with a hypodermic syringe
After 4 hours the edges will be solidly welded and will reach full strength in 48 hours. So my method is to do one side every day. Sequence of sides: There are many methods and I will describe the one which is the most reliable. I join up the sides to each other, one by one, till I have a rectangle. I then lower this over the base making sure that the best prepared or factory cut edges are resting on the base to be welded.
Step1. Lay one long side over many small lengths of wood so that the end just juts out over the last plank and position the side piece over it , like in the photo one below:
Photo one I made those two jigs to hold the vertical piece in position from the stainless steel backs of two broken computer chairs and screwing them to 2 large wooden blocks- crude but effective. Below in photo two is a close-up of the same edge:
Photo two Note the joint overhanging the wooden plank. This is to prevent anything sticking to the joint. Now run solvent down the edge with your syringe, as in photo three.
Photo three
Step 2 Once both end plates are attached to one side you now basically have a long bracket like structure. Carefully lift this out of the way (use more pairs of hands to prevent flexing) and put it aside for a moment. Now lay the other long side down, and invert the assembly previously made over it to form a rectangle. If the tank is anything more than 2 feet long you will have to use support in the middle to prevent sag, like below. When you position the supports adjust their height so that the edges in contact with the lower piece are just lightly resting on it so that you can adjust their orientation and line with just mild pressure from your index finger. Once the edges are lined up to your satisfaction apply solvent to edges at both ends of the rectangle just as you did earlier.
Applying solvent
Important: Determine which side of the rectangle is going to sit on the base piece and before applying solvent make sure there are no irregularities in the edges otherwise a gap will form at the corners. If you look at the picture below you will see that I have placed a heavy steel angle to keep that edge in position. This is the side that will join to the base.
Joining all sides Now the front and back are joined to the sides to give a nice, if somewhat wobbly
rectangle. Step 3 Side braces, Back and Front braces, and Cross Braces Now you have to attach the braces. If you do it later solvent will drip down and spoil the sides of you new tank. (Remember always apply solvent to horizontal edges. Never to vertical edges or the solvent will run down and will ruin the tank's appearance). Take two long strips of acrylic 2" wide and 2 shorter ones for the sides. Place them down and invert the rectangle you have made over them and solvent weld them. Do the sides first and after 4 hours do the front and back. Next day the structure will be quite rigid and strong and will sit much better on the base.
Setting the cross brace in position Put each cross brace in position, clamp it to the longitudinal braces that you glued earlier,(you can use plastic clothes clips) and lightly run a little solvent at the edges. It will hold fast in an hour. General rule is one cross brace every 2 feet connecting the two long braces.
Setting the brace in position - another view
Letting the tank dry
Step 4 - Final stage Lay the base piece on a large smooth surface( floor) over planks like earlier. The planks should be just shorter than the base so that the edges overlap all around by about 5cm. Lay the rectangle over the base and go around carefully aligning the edges with your fingers.. Once it is sitting well you might notice that there is some movement
between the base and the edges. This is because the base flexes a bit. Thicker Acrylic
doesn't flex much- this was a ¼ " piece. To counteract this and ensure a good
contact throughout put paper wedges between the base and the floor in-between the wooden
sleepers like this:
A close-up of the "wooden sleepers" or spacers
Now you are ready to weld. This time load at least four 5 ml syringes with solvent. Take the first one, make sure once more that the sides are not overhanging the edge and run the syringe like you did earlier over all the edges from the inside. As soon as one is over pick up the next syringe Do all the edges in one go. If you missed one or two patches do a second full round immediately. That's it. The tank should not be disturbed by winds, kids or anything else for at least 12 hours. Put some reasonable weight (about 10 kg total) to ensure a gap free join, AFTER you have applied the solvent.
Weighing down the top
Another view
Reinforcing the corners This is not strictly necessary, but I do it anyway. Just lay a triangle of acrylic in each corner and solvent weld it into place. Can't see the joint later anyway as it will be covered by the substrate.
Standing next to the finished product
Wait for 48 hours.( I wait a full week). Place the tank on Styrofoam and fill it slowly to one quarter. Let it stand for 2 hours and check for leaks. And so on up to the brim. If there are leaks don't worry. Mark the area with a marker pen. Drain and dry the tank and apply a line of thickened solvent along all the edges. Thickened solvent.is very simple to make. Take a small glass jar like a Byrlcream bottle, and put a few pieces of scrap acrylic in it and pour in some solvent. Agitate once in a while. In a few hours this will give you a thick acrylic syrup. Remove the piston of a syringe and pour this into the syringe. Fix the piston back and then run this syrup into the leaking area. Or better still the whole of that edge. Prop the tank up at an angle first so that the leaking edge is at the bottom of a V.
Fixing the leaks - no problem!
Finally a few points Since you will be using 3/8th " to ½ " acrylic to make your tank do not cut the material yourself. That will be the only part which will not be DIY. If you need to cut sheets this link will give you the best info: Tools Needed for Working with Acrylic Other than that you will need a packet of 5 ml syringes and 18 gauge needles. Buy the needles separately because 5 ml syringes usually come prefixed with 22G needles. One bottle of Choloroform or Methylene chloride. Unless you work in a medical
establishment, you may find Chloroform rather hard to come by, so Methylene chloride may
be your better bet.
A highly controlled substance in North
America and Europe,
o Some pieces of wood or planks of even thickness and length. o Some home made braces to hold your acrylic in place while you are running the solvent. o A well ventilated, bright room. I hope I was able to cover the topic satisfactorily.
Editor's Note - You might find the following articles useful: TOOLS FOR WORKING WITH ACRYLIC |
