Acrylic/Glass Hybrid Aquarium????

I posted this at RC and only got one reply today. I'm still trying to figure out that forum. I really like this venue a lot better Feel free to tell me I'm crazy but I'm going to make one for myself no matter what!!!

I've been thinking about building my own Nano Tank, approx. 20 gal. "sump/refuge ready". In deciding what material to use, I finally came to realize that using a mix of both materials would probably work best for several reasons.

First off, my 36 gal bowfront already has several scratches on the inside of the glass from substrate getting under the magnetic cleaner. This really discourages me from wanting to use acrylic on the front and side panels of my home made tank. My other thought is the rest of the components of the tank needs holes, slots, bends and good structural ingegrity that acrylic would be best for.

My capability........

I have a well equiped shop for my knifemaking business. This includes a CNC Milling machine, lathe, a large bandsaw and several drill presses. I can cut drill and even MILL glass with diamond tooling but with my intended design idea, all machining would be limited to the acyrlic parts. Any machine work to be done on the acrylic will be a breeze


The actual tank......

Right now I'm busy as heck getting ready for a trade show at the end of the month in Vegas. This idea is keeping me awake at night, I can't wait to draw it up in CAD!!! I probably should have drawn it in CAD prior to this post but I hope I can describe it sufficiently.

My thoughts are to use 3/8" or 1/2" thick acrylic for the base of the tank and 3/8" material for the top. I know it's a bit expensive but this isn't going to be a huge tank. Using the milling machine, I would mill 4 slots in the base and top that the 4 side panels would sit in. This would accomplish several things. First it would be simple to do and provide incredible structural integrity! Second, it would make gluing and assembly very easy. No need for tape, clamps or cursing The front and side panels would be glass, the back panel would be acrylic.

The front panel..............

To me, the worst part of a glass tank is the glue seams at the corners. I was thinking that if the front panel overlapped or extended beyond the side panels I might be able to create some sort of sand blasted affect on the front panel to hide or obscure the two glue seams. This part may very well not work or end up looking like...........CRAP. Right now, it's just an idea that needs more thought. Glass is cheap, I might experiment a little on this part.

The back panel........

Since all of the through holes, overflow, and everything else would involve the back panel it would be easiest to make that black or colored acrylic. I was considering making the overflow in a similar fashion as the tank using milled slots for structural integrity and ease of assembly. I still have to work out the locations of the returns, heights of the overflow box slots in relation to the top of the tank.

Controling dimensions.....

This is the part I'm really hoping for some input on. I would like to build this so that I can easly make or integrate a hood into the design. I'm not to concearned about the exact size of the tank, at least with the first one. My goal is an ultra clean look with no visible wiring, plumping, etc., etc., etc.! From my experience up to this point, I'm probably going to have to start with the lighting fixtures and design out and around from there.

Any feedback or ideas, greatly appreciated. If this sounds like way too much work, I agree but I'm still going to build at least one for my own use!!

mogurnda said:

Do glass and acrylic expand at the same rate in response to temperature changes? May weaken the joints.

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Dave,

I kind of forgot how to read the expansion coefficient charts. From what I can see acrylic should expand at almost double the rate of glass but over a very wide temperature range. It's also very directional based on the size/shape of the acrylic. In other words with 1/4" sheet material, it would expend in length and width with MUCH more than thickness. All considered, my present tank doesn't change more than about 3 degrees as long as the home AC and heat are working. I'm sure the silicone would handle any small change in size.

Someone on the other forum mentioned that silicon adhesives don't bond well to acrylic. My test piece here is pretty **** strong. It's 1/4" thick, about 4" long and I can't pull it apart. Considering the the side panels will be set in grooves, both top and bottom, the silicon will only have act as a seal.

Well, it's still in the R&D phase!

Maybe the way to do it is to make the whole thing acrylic and LINE the inside of the front panel with glass!! :idea2:

mogurnda said:

The reason I was wondering is because I got a crack in my glass sump where the acrylic baffle abuts the glass. I may have just smacked the skimmer against the glass, but thought it might have been from expansion since someone on RC had seen a similar thing.

Click to expand...

That would be in the direction you would get the most expansion with the acrylic. It might have been the cause of the crack. I'm going to cool, then heat a 16" piece of acrylic and measure exactly how much it changes over the widest temp range I can create. I'll report back with my findings.