Need help with a lightweight wood choice?

**dertien616** · 08-26-2011, 09:08 PM

I need some help finding a wood for building these terrariums/aquariums? I am using red oak right now but they are so heavy! I need a wood that is strong enough to build these. Also it needs to look nice stained or painted,and most importantly be lighter that the red oak I am using now. Now i use 3/4" plywood oak veneer for everything showing and for the back, top and floor of the enclosure i used regular 3/4" mdf. they are 4ft to 8ft wide and at least 7ft tall. I need to be able to get matching trim also. If anything i need to know what i should use for the wood you cant see? any advice would be greatly appreciated

**Jerry M** · 08-28-2011, 05:58 PM

How much mdf are you using? That stuff is heavy. You could replace with veneer-core plywood, which would increase the cost but reduce the weight. (maybe the hidden parts could also be thinner?) From the pic it doesn't look like you're using much solid stock. Hardwood-veneer plywood is going to weigh about the same, no matter the species, because most of the weight is in the core, not the veneer (are you using veneer-core, mdf core, or what?) So changing the species won't change the overall weight much.

Lighter species would include: ash, alder, pine, walnut.

The USDA Forest Products Research Lab (you can Google it) publishes a list of domestic species and their weight. Red oak weighs about 48 lb.s per cubic foot. Ash weighs in at about 38, and alder 27.

---Jerry

**dertien616** · 08-28-2011, 09:06 PM

everything you can see is oak plywood venner and the back top and bottoms are sraight mdf everything is 3/4''. i know im going to start using all plywood for back top and bottom also just not venneer. but i also think i will use 1/2'' plywood for that back panel? use a rabbet joint all the way around the back to make it surdy with the 1/2'' plywood do you think this is a good idea or though i use all 3/4 inch with dowels to hold it all together no screws in anything?

**Jerry M** · 08-29-2011, 01:10 AM

I think you're on the right track. Ply is lighter than mdf, and 1/2" ply is lighter than 3/4. But it's a big unit. It will be heavy.

think i will use 1/2'' plywood for that back panel? use a rabbet joint all the way around the back to make it surdy with the 1/2'' plywood do you think this is a good idea or though i use all 3/4 inch with dowels to hold it all together no screws in anything?

I would use fasteners (nails, screws, staples) to attach the 1/2" back (yes, in a rabbet), but you can certainly join the solid stock with dowels, no screws.

**Dal300** · 08-29-2011, 12:49 PM

I think I would be tempted to use aluminum angle with counter sunk machine screws and nuts to hold everything together, and also use some across the center to support the weight.

Of course, that's just me.... if I want light weight, I look at aluminum/wood/veneer as opposed to Plywood or MDF. Both of those are heavy. 1/2" plywood can weigh in at 50 lbs. per sheet. 3/4" plywood can weigh in at 75 lbs. per sheet. MDF weighs even more.

Good luck, We're pullin' for ya!

**dertien616** · 08-29-2011, 06:38 PM

what do you mean exactly with the angle aluminum? do you mean just use 1/2inch back panel with angle aluminum going up the sides or around the whole thing? do you really think that would be necessary? most people have been telling me to put it in a dato or a rabbet joint with some nails or staples.

**Dal300** · 08-29-2011, 08:15 PM

angle aluminum, just like angle iron except aluminum. With the Terrarium it probably would be overkill, but if you were to try to support the same volume of water you would be stressing 1/2" plywood to its max with dadoes and nails.

Also, you can't nail or screw into the edge of plywood and expect any sort of structural integrity.

**Stratman** · 08-31-2011, 05:53 PM

Hey, just wanted to say hi. the terrarium project sounds pretty cool. you should do pretty well if they're going up for sale. Have you ever thought of going to a good hardwood store and look into boat woods, teak (expensive though),mahogany, walnut would be nice for the framing. a good marine plywood is highly recommended for all the paneling areas. will stay nice much longer. finished birch ply is very light in color and pretty beautiful. being a yacht restorer has me firmly in the hard wood family. I'm prattling. sorry... LOL
VERY NICE TO MEET YOU. hope it goes well for you.
stratman