# Constructing Aquarium Accessories With Acrylic Part 2



## Dataseeker (Sep 3, 2006)

A number of cast acrylic components such as these hinge units are available from sources like the ones listed below. They include pulls, handles, and small squares which I show below. These hinges are designed with a raised land along the bottom for cementing. You need to avoid having cement run into the pin portion of the hinges. Guaranteed to give you a bad day. You also should not have anything against the edges being used as a joint such as a positioning weight. The cement will find its way under there for sure.










After gluing all the pieces in place the light fixture is tested for fit.










Front access door is tested.










Small squares are available from the same source as the plastic hinges.










I use these as stops on the bottom of the cover to keep it in place on top of the tank. Guide marks are placed on top with masking tape then the squares are cemented on the opposite side as shown here.










Finished top is put in place on the tank.










Light fixture is put in place to test final fit.










Set up details of the tank itself will be posted in the Aquascaping Forum.
Plastic sheeting and components can be purchased from Plastic Tanks, Plastic Buckets, Plastic Bottles and Labware, DVD Cases - United States Plastic Corporation ® 
Sheeting, cements and supplies can be purchased from Plexiglass Sheet & Plastic Supply for Industrial Plastic Sheet, Rod, Shapes


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## heineken357 (May 25, 2006)

Nice work but wont the light make the acrylic bend? I did somthing like that last year with some thick acrylic I got from home depot, After a few days the lights made the acrylic warp.


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## onemyndseye (May 12, 2006)

".... make the acrylic bend?...."

I had this thought too.... I think its acutally the acryllic "soaking" up water that causes it to bend not the lights per se.

Maybe Dataseeker can ellaborate for us  Excellent posts on working with acryllic none the less  And that stainless framed tank is KILLER!

-Justin
One Mynds Eye


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## Dataseeker (Sep 3, 2006)

The Coralife compact fluorescent fixture I am using comes with an acrylic lens covering the lamps. It is considerably thinner than the 3/16” material of the tank cover. Acrylic needs to be heated to about 250 ° F to be bent. I don’t think heat will be a problem here. If the fixture contained a metal halide lamp, then there would be trouble. Thanks for the comments.


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## Blacksunshine (Aug 11, 2006)

hate to break it to you. But if your using the cheap regular cast acrylic the heat and moisture will make the acrylic panels warp. even in thicknesses up to 1/4". it does not need to be heated to 250deg to warp it. 
for lids you either need to use VERY thick acrylic or polycarobonate. 
Poly carb will not bend due to moisture in thickensses of 3/16" and up. Polycarb is also namebranded as Lexan. 
couple examples of lids I've made.
Here is 1/4" acrylic. Notice the slight bow. the bracing I built into it aids the structual integrity. But as time goes on it has continued to warp. eventually I will need to replace. 









Now here is the lid I made for my 10 gal. It is about half the thickness and poly carb. 

















As you can see even at this thin of material no warpage. I've been using this lid for a few months and even today it sits flush. Poly is slightly more expensive but if your using for a tank lid its very much so worth the extra cost.

Great write up tho, real good detail. I strongly reccomend people try and use acrylic and DIY for as much as possible.

**Edit** 
actually from the coloring of your panels it looks like you are using polycarb. I just didn't see the specific acrylic grade/type mentioned. and it is a very important detail.


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## Dataseeker (Sep 3, 2006)

Blacksunshine, thanks for your concerns and complementary comments.

Below is an excerpt from a listing on the website of a plastics vendor. I wonder if this is what you mean as, cheap, regular acrylic. This is in fact the type of material I have used. There two methods commonly used for manufacture of acrylic sheeting, the continuous manufactured or extruded form and the cell cast form. The cast form tends to be a little more expensive than the extruded form because it is held to tighter tolerances. You are right in that there are a number of different grades in the marketplace. Those with the trademarked names shown below generally conform to the specifications we look for in this material. Polycarbonate is a great material. Its most impressive characteristic is its tensile strength which is about ten times greater than acrylic. Interestingly though the flexural modulus or the ease with which you can bend it is greater than acrylic for the same thickness. This is why we probably don't see a lot of fish tanks made out of Lexan. Oh! and of course because it costs two to three time as much. It can be worked with the same tools and cements used for acrylic.

Acrylic does absorb water to a small degree. .3 % from what I see in various specs. I would not expect that with one side being constantly exposed to water and the other not, that the cover will remain straight as a die. I also do not expect the resulting warping to be that great. I have used this material before over tanks and trays and not had a problem. I do not expect heat to be a problem with this fixture for the reasons stated in a previous reply. The material shown in my post is slightly tinted green. I was fortunate to have a relative that managed an acrylic fabrication plant and for some years provided drop-off scraps from projects that were slated to be dumped in the trash.

Thanks again for your feedback.

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ACRYLIC SHEETS - CAST - Plexiglass
Acrylic (aka Plexiglass, Acrylite GP, Lucite, Acrylite, Optix, etc.) is an amorphous thermoplastic which is optically transparent, unaffected by moisture, and offers a high strength-to-weight ratio. Acrylic offers high light transmittance and can be easily heat-formed without loss of optical clarity. Prolonged exposure to moisture, or even total immersion in water, does not significantly effect the mechanical or optical properties of this outstanding economical and multi-purpose material.


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