Tank Building 3/2/05 I've been reading your DIY tank building FAQ's and trying to get a grip on all the info you have. Call me dumb, but I am getting really confused about different materials and plans for tanks.  I am looking at building a smallish freshwater aquarium, 42" (L) x 24" (W) x 36" (H), by the sounds of it out of glass - this seems to be favoured above acrylic.  <depends on where you live and your material costs, but yes... for most aquarists - glass is easier and cheaper to get, and far easier to work with (less tools/skills needed)> For these dimensions, I calculated the volume to hold 150 gallons or about 570L total. What thickness glass would you recommend, I was thinking 1/2 to 3/4 inch maybe... <1/2" is not thick enough without engineered bracing to do a 36" tall tank. Go thicker, or laminated, or with a four-sided capture> ...and joining it all with silicone. Also, do you think I would need to use different thickness for the sides and base?  <its common, helpful to use a thicker base, and/or silicone in reinforcing strips along the bottom> If there is any other helpful info you can add it would be much appreciated. <I strongly advise you to practice on smaller tanks first. And make no move until you've bought yourself a nice, cheap copy of the "Living Aquarium" by Crescent Books (see used at Amazon.com). This great book includes step by step instructions on a variety of tank building styles/materials> Thanks for all the info on your site, it has helped heaps with many many other questions. Cheers for now, Brenton <best regards, Anthony>

GE 100% Silicone I Hi There, <Howdy> I have seen several posts on the Internet saying this can be used as aquarium sealant. The company seems to be saying that it will only work with them under 5 gallons. Have you used this silicone on larger tanks? Thank you, Mike <This is exactly the same material as is used to make all sizes of tanks. I have used it on glass tanks of hundreds of gallons. Bob Fenner>

Silicone DIY - 2/12/03 Hi, I was just wondering if anyone could recommend an aquarium safe silicone, or how to tell on the container? <play it safe and order an aquarium brand silicone like Perfecto. For the few extra dollars, you'll have peace of mind knowing that it is non-toxic unlike most DIY store brands (anti-mildew...  anti-fish!)> Thanx as always, Jesse <best regards, Anthony>

- Silicone Help - GREAT SITE!!! <And good day to you! JasonC here...> I was wondering if the is any specific technique to applying silicone to seal pieces together? <Don't skimp on the silicone, and the neatness of the whole thing is up to you.> I'm planning to put in Plexiglas baffles in a 10 gal. all-glass tank (being used as a sump) and also contemplating on building a corner overflow out of Plexiglas (not to mention drilling a hole in the bottom of my 55 gal. all-glass tank). <Well, you might want to investigate overflow designs first, and make sure you have all the tools you need - a router comes to mind. Next, spend some time at this link: http://ozreef.org/diy/#OVERFLOW - this will get you on your way for building an overflow. As for drilling the tank, I'd take that to a glass shop and have it done there.> I don't want to jump in and just do it, without professional advice, and end up having a leaky tank... or worse. Any advice on this matter would be greatly appreciated. <As long as asking for advice, see if you can cram a larger tank in there - a 10 gallon tank is ok, but likely it will only add about five gallons to your system volume... more water is always better.> Also, any recommendations on better/cheaper/sturdier material or material combinations (other than Plexiglas) would be nice. <Any sturdy acrylic will work - color is probably not important. Consider finding and visiting a large plastics shop where they often have a bin of cut, scrap pieces which can be had for pocket change. Will save you from having to buy a sheet of material.> Thanks a bunch in advance!!! Loyal WetWebMedia surfer Iona <Cheers, J -- >

Tank Construction Greetings from Arizona, <Hello from sunny Southern Cal.> I've searched the net high and low, and I still feel "lacking", perhaps you could answer this question for me. Can Acrylic be "bonded" or make a water tight seal with Plywood? (can I use screws/bolts in the acrylic?) <Mmm, not "bonded" at the molecular level as in melded to other sheets, but can be drilled, bolted, nestled in a bed of silicone... best on a flat panel with a cut out if using wood for the structural component> Here's my situation - I'm constructing a Plywood Tank and I want to insert either an Acrylic or Glass front. Current Dimension - 96"L x 30" W x 24" H (approx 299 Gallons) Plywood Thickness - 3/4" AC Grade Plywood Glass Thickness (IF USED) - 1/2" Plate Acrylic Thickness (IF USED) - 1" (do you think I could go THINNER HERE??) <Mmm, half inch would bow too much for my liking, appearances... 3/4" should be fine... if supported all along the face of the viewing panel> Waterproofing Agent for Plywood - Epoxy Paint Waterproofing Agent for Glass to Wood - 100% pure Silicon<e> Waterproofing Agent for Acrylic to Wood - 100% pure Silicon?? <Yes, 100% silicone sealant> I'm still in the planning stages, but I want to make the "right" choices the FIRST time. I know the differences between Glass/Acrylic and I think I would rather use Acrylic in this situation, but COST is a factor and so is the "waterproofing issue". <I understand... and have made many such tanks over the last three decades> Ohhh one last comment/question. IF I use acrylic, would you recommend that I attach a sheet of Acrylic or Wood (maybe 3"-4" wide) running the length of the tank on TOP of the Front of the tank for added support for the Acrylic front?? <A good idea, yes, drilled, screwed about every four inches... and such a brace on the back, inside sides as well.> Thank you in advance for any advice you might give!! Soren <Please contact me if you have further questions, concerns. Bob Fenner>

Tank building questions Hello - First let me say that you site is packed with great info. I have been reading it for days. <Wow! Glad you find WWM of use> I like keeping large fish, and they require large tanks. I have built several on my own using 2 part epoxy floor paint over 3/4 plywood and sealed 1/2" glass to the front with 100% silicone (usually GE door and window - never kitchen and bath as it is mildew resistant). <Neat, good for you> Glass has become hard for me to get a decent price so I have been working with acrylic. I have two tanks with acrylic "windows" that are leakers. The first is a 360gal with 1/2", the second is a 630gal with 1". <Mmm, I'd likely try resealing them...> I have been talking to people about this for months and I think the problem is the sealant. Silicone doesn't bond to acrylic very well. Options that I have come up with are drilling the acrylic and frame every 4-6" and bolting it in place, or looking for a better sealant. The better sealant I have found is Sikaflex. It is used on boats to seal windows at depths up to 10'. My original plan was the bolting but the acrylic shop recommended against it as it could stress the acrylic on the holes. What do you suggest? <Hmm, how tall are these tanks? I would likely drill and screw the acrylic, coating over the hardware in the tank with two-part water-proof epoxy, cut away the existing 100% silicone, let it dry for a day or two... wipe the surface down with an organic solvent (we used to use toluene, xylene...) in a well-ventilated setting... and then re-apply a nice, thick bead of silicone... maybe "feathering it out" with a plastic trowel (small ones available at Home Depot, Lowe's...). IF the tanks are only a couple (as in two) feet tall or so... Otherwise, I'm a bit nervous given the width of the wood and acrylic sheets myself. BTW, do look into used glass... especially "old glass doors" for your "humungo tanks"... sometimes these are available from companies that take down old buildings... for very little money> For sealing the wood I have been using 2 part epoxy floor paint. I have been looking at using fiberglass. What are your thoughts on this? Epoxy or Polyester resin? Should I cover the tank with fiberglass mats or just pour the resin and hardener on? <I have made many (hundreds) of tanks for science and industrial purposes using fiberglass cloth stripping (you can buy it as such... I would), and polyester resins... mix the hardener (likely MEK based) with the resin/s as instructions call for (do allow for temperature, time...) and lots of air circulation (have had the worlds worst "highs"/headaches from breathing in too much, too long... One coat, wetting the inside corners first, then apply cloth... wear clothes you really don't like, intend to keep... gloves... Have someone there to help "hand" you things...> I'm also planning a large tank of about 16' long, 4' deep (with 30" window), and 6' wide. Should I go to cement for something this large? <I would consider this approach... and gel-coated fiberglass shells, spun-cast polyethylene forms you might cut out, place a viewing panel in... Bob Fenner> Thanks, John

Re: tank building questions Thanks for the fast reply. The current tanks are 2' deep (360gal) and 3' deep (630gal). I like the idea of using the screws/bolts.  <Do apply another 3/4 sheet to the front/face of the 3' deep tank for strength/rigidity... I would drill pilot holes every six inches use 2 or if you can find them 2 1/4" brass screws, counter-sink the heads in the acrylic...> What size would I need and how often do I need to bolt (i.e. every 4"?) I think the acrylic is thick enough. There is no bowing. The acrylic over hangs onto the tank by about 5" either side. Again, Thank you for the help. John <Perhaps you should consider a career in the public aquarium exhibit design, fabrication business? Please take a look at the book reviewed here: http://www.wetwebmedia.com/afascfishpowell.htm Know you would enjoy, gain by reading it. Bob Fenner>

Custom Aquarium Bob, I am building myself a custom aquarium. It will be 100"Lx 48"H x 42". The back, bottom, and sides will be made of pre-laminated 1" plywood. All the seams will be reinforced on the outside with Steel Angles. The front, viewing area, will be a sheet of 1" prelaminated plywood with a window 92"L x 44"H and a 96"x48" sheet of glass "siliconed" to the inside of the "window". Finally there will be 3 evenly spaced 3" cross ties tying the front of the tank to the back. I am struggling with determining the thickness of the glass. Is 1/2 sufficient or should I go with the 3/4? Any insight you can give would be greatly appreciated. <I would spend the extra money on the thicker glass... Look into some of the fancy laminated brands (Starbrite for instance)... as these may be fine at 1/2", though not cheaper than 3/4" cast... Bob Fenner> Please respond to my home email address. Thanks, Mike

Marine Goop Guys, I am at the stage where I am going to be bonding my acrylic baffles to my 40 gallon breeder sump. I would like to have something a little stronger than silicone as I have had a baffle come out, in the past, while using it. <More likely due to the acrylic and its bowing than due to the silicone.> I have had mixed reports that Marine Goop is a good bonding agent for this application. My question is, do you think this stuff will leach chemicals and cause any toxic stress on reef inhabitants. <I am unfamiliar with "Marine Goop", but have read several reports of various marine life showing adverse reactions to underwater epoxy. I am guessing this "Marine Goop" is something like the epoxy.> If so, do you know of any other materials the would be better for bonding baffles to glass? <Why don't you try glass instead of the acrylic? It is cheaper than acrylic and works just as well. This is one reason I prefer to use glass tanks as sumps vs. Rubbermaid tubs and such.> Many Thanks. Jeff <You are welcome. -Steven Pro>

Plexi glass glue Hi there once again, I have a question about the type of glue people use to put together plexi glass.  <Most folks use a commercial acrylic solvent... like Weld-On> I hear that the best way to glue two pieces together is to use a solvent called Methylene Chloride.  <This is a principal ingredient. Toxic, flammable, not generally available to the public.> can't seem to find it in Home Depot or Lowe's. Do you know where it might be available?  <Check with the businesses listed in your phone directories who sell or do plastic fabrication> I also wanted to ask if you know whether this solvent (Methylene Chloride) can be used to glue plexi glass+regular glass together, or is it just for plexi glass+plexi glass? <Only the latter> On another note, I'd like to thank you for responding so quickly, and for being real informative. It's advise like this, that I wish I had for everything I come across. Your help is greatly appreciated. Thanks, Hamilton, Riverside, CA <Glad to be here helping. Bob Fenner>

Building a tank (particularly coloring the back/ground) To WWM crew, I am planning on building a large tank, by my standards, (at least a 8x2x2). I was planning on building it with plywood. More than anything else I was concerned about how I should paint the inside of the tank. I was thinking about an epoxy based paint, I am really not sure which one would be safe to do this with. I would like to use the tank either as planted freshwater tank or a saltwater shark tank. In the case of the saltwater tank I am even more concerned about the material that I can use to build the tank. I do realize that I have to have no metal in the construction of the tank if I want a shark in it. But I am not sure how to put the tank together without the screws being made of metal. My other concern is the metal in the lighting system how would that effect a shark. I would appreciate any input you may have. <I would skip on using any sort of paint here. Instead, look into the colors that can be added to resins... and coat the inside (and maybe out) with a good quality of laminating type... along with placement, lapping of fiberglass cloth stripping in all corners/joints. Bob Fenner> Thank You, Ali

DIY Glass Tanks Bob I am new to your site and have looked through several of the FAQs but do not know where to post a question that you might be able to answer.  So I hope you do not mind the email.  If there is an appropriate place on your forums to post this please let me know. <Hey Stuart, you've got Gage today.  Feel free to shoot us emails with questions, there is a ton of info archived in our FAQs and many knowledgeable folks on our forums as well http://wetwebfotos.com/talk/  > I am interested in building a large tank, 94 by 36 by 48 inches high. Preferably out of glass. <Never done it myself, I am considering plywood and glass myself, GARF does not recommend making the tank taller than 36inches.> I am having trouble with the glass requirements.  Different tank builders have told me different specs, and I do not know which is needed.  One whom I am not sure I trust would uses standard ¾ inch glass.  2 others whose prices were in the stratosphere said they would use ¾ tempered glass.. <Error on the thicker heavier side.  From what I understand you cannot drill tempered glass, are you going to want drilled overflows?> So my question is; making the tank out of glass, with additional ¾ by 2inch gluing doublers, is ¾ inch glass adequate, or is tempered glass or thicker float glass needed?  3 top braces are planned.   If so would an additional steel frame around the tank be required? <Let me give you some links to some people who have more experience with this than myself. http://www.garf.org/ http://www.ozreef.org/diy/index.html#TANK  > Thank you for your time.  Any additional recommendations are welcome (I know don't build it yourself :-) )  Thank you, Stuart <No way, Go for it!  Just be sure to test outside, thoroughly.  A carpet cleaner with good extraction power is always handy.  Best Regards, Gage>

How to: build your own glass tanks    My name is A.J. and I am looking for some helpful info on building my own glass tank. <Okay>   Particularly in the aspect of placing the sides, front and back pieces on top of the bottom piece or the sides, back and front along the edges of the bottom. <I used to build these (back in the late sixties to the early seventies, with the advent of Silicone and cheap triple strength (replaced glass from companies doing such repairs) quarter inch... building the tanks on their bottoms (mainly to assure flush joints there) and the sides inside (for ease in holding all together while assembling... with or w/o wood-clamps... we used to use tape or nothing (!) on smaller tanks while assembling)> I read an article that told people to put a wooden dowel underneath the bottom piece of glass and assemble the all of the sides on the ends of the bottom piece to make sure that none of the weight would be on the bottom pane thus raising the bottom pane 1/8- 1/4 inch higher to prevent it from cracking. I am sure I have every thing else down pat except that one thing.  I would really appreciate your help in this matter <Raising or more popularly "floating" the bottom has a few advantages, mainly per the issue of how level and planar the device is where the tank will eventually be placed, filled... if you can be assured the "stand" bottom is both planar and level (I would still place a thin piece of foam under it...) then I would do away with raising/floating the bottom. Bob Fenner> A.J. Sacco