wood permanently under water

[john hamilton]

I want to make a tray to contain a thin layer gravel that will lift out of an acquarium.

I thought I would use a plastic box lid cut down to size and with square section strips of wood screwed to each of the edges to form a lip to keep the gravel contained.

Since the wood will permanently be under water ( that's fresh not salt water) would ordinary pine be alright to use (since this is what I have already), or would I be best getting some kind of hard wood edging to make this tray more durable over the long term? Thanks for advice.

[Doug Miller]

Why wood? Why not something that's inherently waterproof? Rigid plastic such as plexiglass would be a much better choice. So would any metal that's not corroded by water contact, such as aluminum or brass. I think my first choice for this project would be 1/2" aluminum angle, which you can find quite cheaply at most hardware stores and home centers.

Or since you're cutting your plastic box lid down to size anyway, cut it about an inch oversize. Heat it with a heat gun or a hair dryer and use pliers to bent the edges up to form a half-inch lip all the way around.

Nope. It'll rot. Almost any wood will, if you leave it immersed in water long enough. Some will rot faster than others, and pine will be one of the fastest.

For continuous immersion, if you insist on using wood, you really need either lignum vitae or ipe. You might get away with redwood. But the other materials mentioned above are vastly better, and don't run the risk of leaching anything into the water that might be harmful to your fish.

[RonB]

I agree with Doug. plastic such as plexiglass or polycarbonate. Readily available and will last forever. If you used thicker sheet (1/4") you could even cut strips to glue around the edge to help contain the gravel. Just make sure your glue is compatible with the plastic and most plastic glues will handle the two materials mentioned above.

A few minutes in the local hardware or big box store should have you fixed up.

(BTW polycarbonate is extreme overkill but it is often available in the glass and sheet plastic display racks).

RonB

[salty]

Make sure your glue is compatible with FISH.

[RicodJour]

Fish glue should be compatible with fish, and, if it's not, well, you'll at least get some more glue out of the deal. ;)

"Glue can be extracted from fish by heating the skin or bones in water. The purest form of fish glue, made from the membrane of the air bladder (swim bladder) of certain species of fish such as the sturgeon, is also called isinglass (fig. 1). Isinglass can be produced from various species of fish using diverse manufacturing processes. Depending on the manufacture, the purity of isinglass can vary. Historic sources do not always specify which part of the fish was used to make the glue.

There is no record telling us exactly when and where the first animal or fish glue adhesives were used. However, it is known that at least

3500 years ago these adhesives were used in Egypt. Even though Egyptian records do not describe in detail the adhesive preparation process, they do tell us that it was made by being melted over fire and then applied with a brush (Darrow 1930, 9). " R

[J. Clarke]

You also need to make sure that your glue is compatible with the _fish_, or whatever it is that's going to be living in that aquarium.

[scritch]

The wood won't rot. Wood fungus needs damp, not wet, wood to live. There has been 45,000-year-old kauri dug up in New Zealand that was still workable, and bog and river logging is very popular. However, I'd make sure your screws are stainless steel to avoid corrosion. And regarding durability, how often are you going to handle this tray? I can't imagine that you would be changing fish tank gravel often enough to wear out anything harder than balsa wood.

scritch

[salty]

A fish tank is a very "nutrient rich" environment. It's not just water.

[-MIKE-]

Yeah, it's nothing like a river or lake.

[salty]

Correct!

[-MIKE-]

I was being sarcastic.

[salty]

Well, then take it as a bonus that you were also correct!

[DGDevin]

Or get some plastic fish.

[Larry Jaques]

On Wed, 24 Feb 2010 14:17:13 -0000, the infamous "john hamilton" scrawled the following:

Try MDF, John. It won't take a month to break down like pine will. It'll dissolve within minutes, hours at the most!

-- "Politics is the art of looking for trouble, finding it whether it exists or not, diagnosing it incorrectly, and applying the wrong remedy." -- Ernest Benn

[Stuart]

And plastic wood? 8^)

[Derek Lyons]

Why do you need to lift it out?

D.

[Derek Lyons]

The glue needs to not only be compatible with the plastic, but compatible with the fishes as well. I'd google around for places that cater to folks who roll their own aquariums.

D.

[john hamilton]

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Many thanks to all. I want to lift it out to clean the gravel which gets a kind of dark green algea growing on it after six months or so.

Salty Dog when you say my local store should fix me up did you mean B & Q or Homebase ?

[Lew Hodgett]

------------------------------------------ Not a good application for wood.

Glue can be a PITA.

Use plastic strips held in place with brass/bronze fasteners available at any decent hardware store or marine chandlery.

Lew

[Larry Blanchard]

One of my other hobbies is raising tropical fish. The best waterproof glue is epoxy, but wait a week or two after assembly to ensure that it's cured.

There are some sealants designed for aquarium use, but that's a very weak bond.