# Construction grade wood in the tank



## saulrich (Mar 1, 2009)

I've decided to create a 'muskoka' theme for one of my tanks, so I have built a little dock like structure with wooden 'piles' that lead from the sand substrate up to slightly above the tank. I didn't want to spend a fortune on larger poles, but was able to achieve the look i wanted with 4 inch dowels.

Does anyone know how I should seal these pieces? Are there any wood sealant products that are safe for a fish tank? I know there are 'non-toxic' products out there, but I'm not sure that refers to prolonged immersion in a closed system like an aquarium.


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## Abb (Mar 7, 2009)

could you not just tie them together with something? why use a glue?


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## saulrich (Mar 1, 2009)

no - sorry - i need to seal the wood to prevent mould, mildew and such on the parts above water.


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## saulrich (Mar 1, 2009)

This is my plan - two dowels that will be both above and below the water. I'm concerned that mildew will form on the spot between the wood and the water. If it was just above the water, i'd seal it, but I'm concerned about sealing parts of the wood that could be submersed.


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## ameekplec. (May 1, 2008)

If you use any sealer on the wood, it will kill your tank - anything to kill mold/mildew will kill your fish. 

What you can do is use larger longer pieces of driftwood (tree limbs, etc) for your dowels - it'll look good too


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## saulrich (Mar 1, 2009)

Yeah - that might actually be better cause the dowels look like, well, dowels. I'd have to shape them into 'piles' to get the dock effect, but if I shaped it myself, it'll keep that rough look. i was gonna rough in the dowels a bit myself (dremel in some worm holes and stuff), so maybe the driftwood is a better starting point.

Thanks.


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## saulrich (Mar 1, 2009)

just thought on a probably obvious question - but can any science type people explain why my untreated cut wood from rona gets all mildewy, but anything from the wilds seem to stay good. Does soaking/aging the wood do something? Although I think I now prefer the idea of starting from driftwood anyway, could i just soak the dowels like driftwood?


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## ameekplec. (May 1, 2008)

Oh, the other thing that just struck me about using cut lumber is that one should not use anything coniferous (pine, cedar, etc) as they contain resins which can be toxic in your aquarium.

The reason for the mildew/mold? No idea, but in nature stuff rots too - the bark tends not to rot as fast, but the wood on the inside breaks down pretty good.


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## dl88dl (Mar 8, 2010)

You can use marine epoxy to seal the dowels and they are extremely strong plastic and they are non toxic when hardened.


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## Aquatic Designs (Apr 2, 2006)

If the dowels are hard wood, what's wrong with just using it the way they are? They will age in the aquarium like they would in the wild. And they should take forever to start to rot. At least i'm thinking until your bored and do something new. And they are easily replaceble and cheap. 

BTW great idea. I built a diagramma as a kid for one of my first tanks. It's been awhile since i heard anyone thinking outside the peruvial glass box.


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## BettaBeats (Jan 14, 2010)

ameekplec. said:


> Oh, the other thing that just struck me about using cut lumber is that one should not use anything coniferous (pine, cedar, etc) as they contain resins which can be toxic in your aquarium.
> 
> The reason for the mildew/mold? No idea, but in nature stuff rots too - the bark tends not to rot as fast, but the wood on the inside breaks down pretty good.


No one should use coniferous trees for ANY animal.. including pine and cedar shavings for bedding in hamster and rat cages. They contail phynols/oils that are highly toxic.


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## saulrich (Mar 1, 2009)

I went ahead and put it together without any sealant on it, and sure enough, mildew has formed on the 'posts' just above the water line. I think I'll go with the marine epoxy - I just hope it doesn't end up looking too glossy.


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## 50seven (Feb 14, 2010)

The lumber you find at a lumber store has been kiln dried to make it stable to fluctuations in humidity when used in ordinary homebuilding and cabinetmaking, etc. This is to keep the lumber from warping and twisting, but also removes most of the natural moisture and oils that protect the natural wood. That's why it discolours the way it does. 

Usually dowels in the lumber store are oak or poplar. Oak is harder and will resist rotting better and not turn black so quickly as the poplar will (poplar is more white and has little visible grain)

The best thing to coat it with might be a lacquer based paint or clear-coat such as would be used by kitchen cabinet makers. Once the coating cures after a few weeks, it will be impermeable and won't leach any chemicals into the water. You can get any finish you want, but unless you have a buddy in the cabinet business, it's really not worth the trouble. 

A better solution might be to get some epoxy resin from Canadian Tire in the automotive body repair section. Make a small batch and paint it on with a brush.


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## Aquatic Designs (Apr 2, 2006)

You could use pool paint. Try waxing the posts with parafin wax. Make sure it's non scented.


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## dl88dl (Mar 8, 2010)

saulrich said:


> I went ahead and put it together without any sealant on it, and sure enough, mildew has formed on the 'posts' just above the water line. I think I'll go with the marine epoxy - I just hope it doesn't end up looking too glossy.


My friend build a 8' 300gal tank made of 3/4" plywood and the front panel is glass and he use a marine epoxy light blue color with matt finish.


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## saulrich (Mar 1, 2009)

The dowels are poplar - maybe I'll see if I can just replace the dowels with oak and see if it's as simple as that. Not exactly a costly investment.

If that doesn't work, I'll test a couple dowels with the epoxy out of the tank and see if it maintains the look I want, then if all that fails I'll dry out a proper sealant over a few weeks. Woodworking is my other hobby, so I don't mind having batches of different sealant around - I'll find a use for it somewhere. I have to seal the top 'dock' part of it anway (I didn't do it before because my basement 'workshop' is unventilated, so anything like that I wait til the spring).


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## dl88dl (Mar 8, 2010)

Yeah, it is best to use the epoxy outside or in the garage with the door open


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