I’m considering making a tank using plexiglass or acrylic. For my application, I want to build a sump to fit in my aquarium stand. I believe that my dimensions are going to be something like 24l x 12w x 16h (which is about a 20g tank). I plan on only putting about 6-8 inches of water in to start since that is the optimal range for the skimmer. I also figure that, if for some reason my power shuts off, the water level in my 55 is only going to have to drop about 1/2 inch if that much, so the sump is going to have to hold about 1 1/2 gallons of extra water, or around another 1" of water. So at the very most, I don’t expect the sump to be much over 1/2 full.
Does anyone know how much it matters if the tank is made of extruded or cell cast acrylic? I have read a little bit about the different types of acrylic, and it seems like in extreme pressure situations, like in 30" tall tanks there is the chance of the extruded acrylic’s seams not binding together correctly and failing, where that is a lot less likely using cell cast acrylic.
Also, because I don’t care about scratching or clarity of the walls of the tank, if I decided to use plexiglass, are there different types that I need to be aware of? I can’t seem to find anything saying there are different types.
Any recommendations on how to bond either the acrylic or the plexiglass together?
From what I’ve read extruded can become brittle over time and have less strength then cell cast, also it doesn’t have near the clarity (like you mentioned) as the cell cast.
I’m not even sure if I used cell cast or extruded on my overflow, but it seems to work fine albeit it hasn’t been up and running for very long, but again like you I didn’t care much for clarity.
As I said in the other post my plan was to bond with PVC cement (or all purpose cement) and then go back over the seems with silicone to help create the water tight seal, I have no idea if it is the best way (ended up bending), so hopefully someone with more experience can chime in.
I don’t see where it is more brittle over time or anything like that. The only problem they really talk about is if you use fast drying solvent cement’s to bind your seams, they have a chance to fail or not seal completely.
Ok, first, Plexiglass is simply a brand of Acrylic. It is the same material. For the extruded vs. cast, I have read to always use cast, but I am not 100% sure why here. I do KNOW that PVC cement will not bond acrylic. For that you need an ACRYLIC solvent, not a PVC one. You can buy them online, look for “Weld-on” brand products.
Ok, I spoke with a couple of people from Plastikote. They supply the acrylic and Plexiglass to Lowe’s. Both people I talked to said that using extruded Acrylic is more than enough for an aquarium. The only thing he recommended was going to a little thicker piece than you would use for cell cast. He felt that up to 13" you may want to use 3/8" acrylic as opposed to 1/4", from 13"-24" he would use 1/2". The other thing he said is that, regardless of what type of acrylic you use, you want to make sure you get a specific solvent that does not dry too fast. He recommended the use of a Weld-On product, but was not sure which it was. I am assuming he means the Weld-On #4, since that is what I have been seeing most people building their aquariums out of. He also said that I should call one of our local plastic distributor’s and see what they recommend for use in an aquarium. He could not recommend anything specifically. He just said to make sure it was a 2 part solvent cement. The idea is that the longer it takes to dry the better. If it dries too fast it will not create a perfect seam and it is possible that it could fail. But he said, that is possible with any type of acrylic.
The other thing he said is that over the last 10-15 years, the technology used to create extruded acrylic is much better than it used to be. The chemical reaction that they are creating produces a much cleaner and stronger piece of extruded acrylic than it used to, and that 10-15 years ago, he would have told me to stay away from extruded acrylic for an aquarium.
So, take that as you will, but it doesn’t sound like it really matters much for building a sump. It’s only important if you want a piece of acrylic that won’t scratch easily, and that is where Cell Cast acrylic is better than extruded.
I went on a plexi tank building splurge about 7 years ago. i used whatever i could find at lowes, Kaufman glass or HD. I ve had some of those tanks in continuous use since then, no problem. even with my poor glue job. still hold water. one is a 40 breeder size. 36x18x16 high. thats about as high as you want to make using 1/4 inch acrylic. and you should use a lip around the top to frame and stiffen the sides. GARF has some nice calculators and DIY pages on building one.
i buy the glue, WELDON 3 or 4 the thin stuff in a can, and WELDON 16 the thickened stuffin a tube and the hypo needle bottle applicator at Kaufman glass, on Quigley, near the farmers market.
I will call Kauffman Glass first thing Monday morning, but are you able to buy sheets of acrylic from them? And does anyone have any idea how much a 3/8" sheet of cell cast costs from them? As of right now, I am looking at spending right around $100.00 from either E Street Plastics or Delvie’s Plastics to build a 24l x 12w x 16h. I figure that will do me just fine for right now, and in time I have a 10gallon glass tank that I could probably use as a fuge once I get the nerve up to cut a whole in it.
I know that I could probably get away with the other acrylic, but Lowes only sells it in 1/4" and since I am going 16" tall, I would feel better with 3/8".
Is the Weld-On #16 a must have? or could I pick up some aquarium epoxy from Lowes to seal the corners? I already ordered the Weld-On #3 from Delvie’s along with my black acrylic sheet that I will be using as a background. Went a little overboard on the background, but I like the idea of the acrylic back there as opposed to either painting or using a sheet of the aquarium background.
Weld-on 3 or 4 is a must but do not use aquarium sealant as it is just silicone. Most of the places you mention might cut the acrylic for you and then you would only need to pay for that. Don’t forget top bracing.