# Wood box instead of aquarium?



## oneshot (Mar 5, 2010)

It seems the prices of aquariums skyrocket when they get over 55 gallons, so I was wondering if I could just build a box out of wood, put pond liner in, make a full glass front that would screw on, and make the top out of glass for the lighting and feeding?

I also envision cutting a 3' X 3' hole in a wall in our house (interior wall, between the foyer and the living room) and building a double sided viv. Could trim it out all nice. But I digress.

Seems like it would be sooooo much easier to customize, for example drilling glass requires a special drill bit, etc.

Or am I missing something?


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## Pumilo (Sep 4, 2010)

It's been done. People make REALLY big aquariums out of plywood with a glass front. Usually instead of a pond liner though, they will use fiberglass resin or just marine epoxy. Google Plywood fish tank.
Doug


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## Owlbassboy (Oct 9, 2010)

Yeah go with fibreglass resin mate, the wood could sweat and rot behind pond liner.


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## angry gary (Dec 9, 2009)

put an ad in your local penny saver or want ad magazine and craigslist saying you are looking for an aquarium over 75 or 125 or whatever and say what you are wiling to pay. you would be surprised at the amount of response you will get. i put an ad a while back asking for 55 and bigger and said i was willing to pay 50 cents a gallon for the nicer tanks. i was swamped with calls.nothing like picking up a 55 gal tank and glass lid for $25.

AG


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## the_deeb (Apr 21, 2008)

Pondliner is feasible and is probably the cheapest method, but there are better ways to seal the wood. It'll be easier if it's going to just be a vivarium because you don't have to worry as much about the pressure and weight.

I built my tank out of plywood (see link in my signature for lots of construction details). 

The DIY tank building section here: DIY Tanks - MonsterFishKeepers.com has lots more examples.


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## the_deeb (Apr 21, 2008)

I wrote a pretty long thread on the MFK site reviewing the pros and cons of some of the various methods of sealing a plywood aquarium. I've pasted it below in case you find it useful. 

*1. Two part epoxy paint*
The most commonly used and reliable epoxy paint for plywood aquarium builds is Sweetwater epoxy available from Aquatic Ecosystems : Aquatic Eco-Systems: Koi Supplies - Sweetwater® Epoxy Paints, 1 Gallon
It is completely non toxic when cured and has good adhesion to plywood. This epoxy paint has solvents mixed in and is only 65-72% solids. The solvents mean that it ships as a hazmat product and will let out strong, toxic fumes while curing so a well-ventilated workspace is essential when using this product. It also means that it has a nice consistency and is very easy to work with and apply. Sweetwater can be used as a stand-alone product for waterproofing a plywood aquarium. While several members have done this successfully, others have reported that leaks have developed after long periods of use due to stress fractures forming at seams or pinholes due to falling decor. It is therefore important to have a well built structure when using this product as excessive flex could potentially contribute to leaks. Silicone will adhere well to Sweetwater so when sealing a tank with this method you should first apply the Sweetwater and then silicone in your viewing panels.

Epoxy paint summary

Pros: Easy to apply, available in a range of colors, silicone will stick to it making window installation easy.

Cons: Toxic solvent requires hazmat shipping and well ventilated workspace, does not add structural strength to a build, potential risk of failure in an inadequately supported tank with excessive flex.

*2. Fiberglass resin with epoxy paint top coat*
Reinforcing a plywood coating with fiberglass is an excellent way to add structural strength to the build and impact resistance to your coating. The cheapest way to apply fiberglass to a build is to use fiberglass resin to wet out the cloth. Lightweight fiberglass cloth and fiberglass resin are available from online vendors and are also generally easily found in “big box” stores like Home Depot and Lowes in the US e.g. Shop Elmer's Gallon Fiberglass Resin at Lowes.com

Fiberglass resin is generally polyester resin and requires a small amount of hardener to be added as a catalyst. Effective application of fiberglass takes a little skill but is fairly easy to learn with a little practice. It is important to avoid bubbles in the fiberglass layer which may ultimately pop under water pressures and compromise your seal. Polyester fiberglass resin is fairly cheap but has a very strong smell and requires a well ventilated workspace. In addition, it is not sufficient as a standalone waterproof barrier coating and will leach out chemicals into your aquarium water. Therefore, you must finish a fiberglass resin coated aquarium with a non toxic, waterproof topcoat. Sweetwater (see previous section) is an excellent product for this purpose. Using Sweetwater over a layer of fiberglass overcomes most of the potential cons of Sweewater alone.

Fiberglass resin + epoxy paint summary

Pros: Relatively cheap way to add structural strength and impact resistance to your build, epoxy topcoat is available in a range of colors, silicone will stick to it making window installation easy.

Cons: Fiberglass application requires some practice and skill, toxic fumes in the resin and paint require well ventilated workspace, fiberglass resin is not sufficient as a stand-alone barrier coating.

*3. Two-part marine epoxy resin*
There are many different brands of epoxy resin available but only true two-part marine epoxies should be used for plywood aquarium builds. These epoxies have a long established and successful history in waterproofing wooden boats. They differ from epoxy paints in that they are 100% solids. Several brands are available but some tried and true options include:
West Systems 105 (one of the more expensive): WEST SYSTEM | Epoxy Resins and Hardeners
US Composites (cheaper option): Epoxy :*Epoxy Resins and Hardeners
Max ACR (newer, relatively affordable epoxy being marketed specifically for aquariums): http://cgi.ebay.com/EPOXY-RESIN-AQUA...item4831f75a83 (search for the seller “polymerproducts” on ebay)

There are many other marine epoxy brands out there that you could use but these three cover the spectrum of price and have all been successfully used in waterproofing plywood aquariums. Marine epoxies come as a resin and a separate hardener that have to be mixed in a precise ratio. It is best to use slow hardeners when sealing a tank with these products to give you a longer working time and better penetration into the wood. The West Systems use guide is an excellent resource to learn how to properly use marine epoxy: WEST SYSTEM | Use Guides
I strongly recommend reading every section of the guide before beginning to work with these products.

Marine epoxies can be used as a standalone product to provide a completely waterproof and non-toxic coating for a plywood tank. However, they are fairly brittle when cured and can be susceptible to stress fractures at seams and damage from impact which will compromise the barrier coating. Please see http://www.jonolavsakvarium.com/eng_...t/article.html
The best way to avoid these issues is to incorporate a layer of fiberglass cloth into the epoxy resin. Epoxy resins can be used to wet out fiberglass cloth in much the same way as polyester fiberglass resin but offer several advantages. There is not strong smell, the cured resin layer is completely waterproof and non toxic and is slightly less brittle than polyester resin. With the exception of cost, epoxy resin is an all around better option than polyester fiberglass resin. As discussed above, wetting out fiberglass cloth does take a little practice but with a little skill is an excellent way to add significant structural strength to your aquarium.

When used with thickening agents such as colloidal silica, marine epoxy can also function as an excellent adhesive, particularly for slightly loose joints or joints where you cannot deliver high clamping pressure. It can therefore also be useful as a waterproof adhesive during the construction and assembly of a plywood aquarium.

Silicone will adhere well to epoxy resin so waterproof your tank first and then silicone in your glass viewing windows. Epoxy resins can be tinted if you want a colored coating but will usually still show some wood grain. Sweetwater epoxy can be used as a topcoat if solid color is desired.

Two part marine epoxy summary

Pros: Can add significant structural strength to a build, particularly when used with fiberglass. Minimal smell. Effective standalone waterproof barrier layer. Silicone will stick to it making window installation easy.

Cons: Expensive, can suffer from stress fractures if used without fiberglass on an inadequately supported structure.

*4. Pond Shield*
Pond Shield is a 100% solids two part epoxy resin available from Pond Armor Pond Armor - Non Toxic Epoxy and Polyurea Pond Liners and Sealers It is different enough from the marine epoxies described above that I thought I should give it its own section. Pond shield is non toxic (so no Hazmat shipping is required). It has practically no odor and is safe to apply indoors. Pond shield is an extremely thick epoxy which can make it somewhat challenging to work with. The black pond shield is the thickest and has a consistency slightly thinner than honey. It can be thinned slightly with denatured alcohol to make it more workable, but thinning also increases the risk of not getting the required thickness in a single coat. One 1.5qt kit of Pond Shield claims to cover 60sq ft at 10mil thickness. For many applications a single coat is sufficient to get a 10mil coat that is completely waterproof.
Pond Shield is best suited to waterproofing well-supported structures with no flex. If you have any concerns about the integrity of your seams it is best to fiberglass them to prevent the formation of potential stress fractures. Pond Shield is ideal for sealing concrete tanks. While it adheres to wood it adheres even better to concrete so one option when using it on a plywood tank is to first line the inside of the tank with Hardiboard. If you instead choose to apply it directly to a wood aquarium it is best to first do a light wash with 30-40% alcohol-thinned Pond Shield to get better penetration into the wood and follow this with a single coat of unthinned, or very slightly thinned Pond Shield.
In my personal experience I have found that the thick consistency of Pond Shield can make it challenging to work with and results in several areas that require touching up after the initial coat. Careful inspection and touch up is critical to the success of using this product.

Pond Shield summary

Pros: Completely non-toxic and odor free. Available in a range of colors. Requires only a single coat and touch up. Silicone will stick to it making window installation easy.

Cons: Thick consistency can make it difficult to work with. While it remains somewhat flexible after curing it is susceptible to stress fractures in poorly supported structures.

*5. Liquid rubber*
These waterproofing products are elastomeric emulsions that remain highly flexible after curing. While there are a number of these products available, some examples of those that have been successfully used with plywood aquariums are
Zavlar / Permadri Pond Coat (in the US) PermaDri | Pond Coat
and Ames Blue Max Ames' Blue Max Liquid Rubber Coating .
These products have minimal odor and are easy to apply. Zavlar/Pond Coat requires several coat to achieve a 40mil thickness that provides a waterproof barrier. One gallon will cover 30sq ft at 40mil thickness. The primary advantage of these products is that their incredible flexibility, which allows them stretch and resist fractures in inadequately supported structures. However, it is still a good idea to use drywall tape on seams while applying these products in order to to reduce potential stress on the coating at these spots.
Zavlar/Pond Coat will initially appear brown and will dry to a black coating. However this black coating will gradually turn back to brown after being submerged for a period of time. Ames Blue Max dries to a translucent blue color.
Zavlar/Pond Coat will not cure when applied over silicone. Similarly, silicone will not adhere to cured Pond Coat. This incompatibility with silicone is a disadvantage of these products but is easily overcome. One strategy is to use butyl rubber, polyurethane caulk or 3M 5200 instead of silicone. The viewing window should be installed first with one of these products and then the Zavlar/Pond Coat is used to waterproof the inside and paint over the cured caulk. As an additional measure of security I recommend using a small amount of epoxy to first waterproof the area where the viewing window will be installed, such that epoxy layer bridges the seam between the zavlar and caulk. This way, in the event the zavlar separates from the caulk the epoxy provides an additional waterproof layer that will prevent leakage.

Liquid rubber summary

Pros: Highly flexible coating resists fractures even in poorly supported tanks. Easy to apply. Minimal smell.

Cons: Limited choice of colors (brown in the case of Zavlar/Pond Coat, bright blue in the case of Ames). Incompatibility with silicone slightly complicates window installation.


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## vjf000 (Jun 14, 2008)

I have been thinking about doing this, using gorilla glue to hold it together with a couple of brass screws during building process and maybe a base of some plastic container like "kiss" container from kmart, build the box to conform to the kiss container as a waterproof base and using the gorilla glue to both seal the sides and adhere the coco fiber to, what do you think?


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## vivbulider (Jan 23, 2010)

vjf000 said:


> I have been thinking about doing this, using gorilla glue to hold it together with a couple of brass screws during building process and maybe a base of some plastic container like "kiss" container from kmart, build the box to conform to the kiss container as a waterproof base and using the gorilla glue to both seal the sides and adhere the coco fiber to, what do you think?


i would just use plywood and epoxy it will be cheeper and it would be hard to get gorilla glue 100% waterproof


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## vivbulider (Jan 23, 2010)

plywood tanks are a great alternative to glass and very cheep i built a 240g tank 4',4',2' for around 250


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## vjf000 (Jun 14, 2008)

i had never heard of ames blue max, and its non-toxic!


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## Dendro Dave (Aug 2, 2005)

What about truck bed liner? I've heard of people using that successfully I think...


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## jpstod (Sep 8, 2005)

Dendro Dave said:


> What about truck bed liner? I've heard of people using that successfully I think...


i have been considering it..But have yet to do it.
i currently have a 72" W x 72" H x 30" D... Cage I am looking into options for.


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