Custom Canopy (Lexan vs Acrylic)

[Daniel Bodily]

All Reefers out there,

Working on a custom canopy for my 152 Gallon tank just seeing what people thoughts on open top tanks and floating canopies are. Is there lots of water that is splashed out of the tank? Other thought on why or why not going with a open top tank?
On a side note is there any problem with using Polycarbonate (lexan) vs acrylic on tanks and sumps?
Also is there anything that is harmful to fish or corals by using Polycabonate(lexan)

I'm a custom furniture craftman and I really have not found any canopy that I like. This is what I'm building for the aquarium it is something that I have built for homes over the dinning room tables but thought it would be a great design for a canopy on a rimless aquarium

My plane on the lights is to use Kessil A360 in place of the LED lights.
Working with kessil right now to get the heat exchange and air flow right to keep the light cool.

If anyone has a better idea for lights I would also like to here it?
Thanks

Dan Bodily
Bella Rose

 

[bios]

You can do a rim in polyc. Or in acrylic and leave open the center where lights acts take in mind that some polyc stop the uv and filter many other lights lengths

 

[Daniel Bodily]

But what is the pros vs cons to rim less aquariums?
Does polycarbonate have any effect to the reefs?

 

[redfishbluefish]

My number one reason for not having an open top tank are carpet surfers. I've lost too many expensive fish to carpet surfing, and no more! If you go with a floating canopy, you might wish to include a screened top on the tank.

 

[Daniel Bodily]

Screen what kind of screen? plastic?
I don't love the idea but I also get your point.
Any other ideas on stopping fish from jumping from the tank?

 

[Lowell Lemon]

But what is the pros vs cons to rim less aquariums?
Does polycarbonate have any effect to the reefs?

I am not sure what you are asking? Are you asking if polycarbonate is okay for aquarium construction or for light lens use?

 

[Daniel Bodily]

Is polycarbonate ok for fish and corals?

 

[redfishbluefish]

Is polycarbonate ok for fish and corals?

Yes, I've used it for baffles in sumps.

 

[redfishbluefish]

Screen what kind of screen? plastic?
I don't love the idea but I also get your point.
Any other ideas on stopping fish from jumping from the tank?

Yes, plastic. Bulk Reef Supply, Marine Depot, to name two, sell screen tops for tanks. Not pretty, but keeps fish from jumping.

The other option is to pick fish that have less likelihood of jumping.

 

[Daniel Bodily]

I think that I'm using lexan on the sump and (acrylic or glass) on the tank.
I like that lexan doesn't crack when being cut and worked
Acrylic is cheaper but glass is harder to scratch

 

[Lowell Lemon]

Polycarbonate has been used for tank covers or lenses for over 30 years by my company. I use it in conjunction with acrylic aquariums as an access cover. No problems with cytotoxic leaching as a lens. Using Polycarbonate for an aquarium is problematic due to the higher rate of flexure and difficulty in making strong bonds for the seams. Never seen it used this way except as a glass / polycarbonate laminate used for bullet proof windows. I have never seen a polycarbonate tank for water use.

I would use acrylic for a canopy due to the many colors and strength of bond. Again bonding polycarbonate is problematic and few solvent welds hold to the strength level as compared to cell cast acrylic.

 

[Daniel Bodily]

I really don't like the look of the Screen its a window screen frame
there has to be something better then that on the top of the tank

 

[Lowell Lemon]

If you are going to make a sump you will have more success with cell cast acrylic instead of polycarbonate. I have never seen a product that would bond polycarbonate strong enough to make even a sump.

In a glass sump I could see a polycarbonate panel use as a wall but eventually the silicone would let go and need to be replaced at the junction of glass and polycarbonate

 

[Daniel Bodily]

Interesting my work only uses polycarbonate for airbag testing we glue it all the time and have never had a seam break

 

[Daniel Bodily]

Some fixtures are applying 7500 pounds per square inch of force on glued seams in polycarbonate

 

[Lowell Lemon]

Interesting my work only uses polycarbonate for airbag testing we glue it all the time and have never had a seam break

What are you using the two part 3m adhesive?

I am ready to learn more about plastics anyday starting now.

 

[Daniel Bodily]

I don't know what it is I will check.

 

[Daniel Bodily]

I recommend that you speak to your polycarbonate supplier/molder to discuss why this might be happening. For instance, the raw resin supplier may be adding a mold release to improve molding with polycarbonate and allow the polycarbonate to release from the metal mold easier. If a monomeric mold release is used, it can sometimes migrate to the surface and push the adhesive away from the bond line, causing interference with adhesion over time. If they are using a polymeric mold release, it cannot migrate as easily and should not have a negative effect on adhesion. Or, maybe the polycarbonate molder is spraying a Teflon® mold release every 200th shot to help the part release from the mold.


I also suggest asking the polycarbonate supplier/molder about the levels of stabilizers being used. Most stabilizers in the plastic are at acceptable levels and do not interfere with bonding. On occasion, however, the supplier/molder adds additional stabilizers to give light or heat resistance and stability to the plastic. These stabilizers can also migrate to the surface over time and destroy a bond line. To be sure, you can submit samples of the polycarbonate before and after heat aging to an analytical laboratory to run a solvent extraction on the surface of the plastic, to see if there is a contaminant at the surface, and to identify the contaminant. I have even seen contaminants like finger oil at the surface of the plastic migrate along the bond line and eventually degrade the bond strength.

 

[redfishbluefish]

There are a number of Weldon products that will "glue" Lexan (polycarbonate). Yes, it can be bonded together!

 

[Lowell Lemon]

Some fixtures are applying 7500 pounds per square inch of force on glued seams in polycarbonate

With that bond strength you should have no problem unless polycarbonate absorbs more water than acrylic. I know it is less rigid than acrylic and adsorbs more impact before breaking. That could suggest that it may require different designs to prevent bowing on longer spans. Interesting you learn something new everyday.

I made a series of protective cover for a local paper mill 25 years ago and it required bending and bonding the machine guards. I used a solvent weld the only thing I had available then. Worked great for that application.