which woods sink right off the bat, when dry???

[Magnum Man]

I've noticed spider wood, sinks right away, even when quite dry... what other woods sink right away

 

[WhistlingBadger]

Any of them, if you put enough stainless steel, 1/2" x 2" lag screws in the bottom of them.

 

[MaloK]

Mopani and Malasian drift wood, most of the time are dense enough to sink directly.

 

[AJ356]

Mopani and Malasian drift wood, most of the time are dense enough to sink directly.

Yep, definitely mopani

 

[jaylach]

I think it depends a lot on if the wood is foraged or bought from a store...

If foraged a lot depends on the condition of the wood. Even if the same species of wood a foraged piece could sink or float.

If the wood is purchased a lot depends on how the wood was prepared by the seller.

The weight option stated by @WhistlingBadger does work but I've never just put bolts in the wood. If I had a stubborn piece I'd drill holes and fill with BB's or plant weights. Seal the hole with silicon and use shavings from the drilling to cover the silicone before it sets. If you do it right you would hardly ever know that the wood was drilled and weighted. This also keeps the metal out of the water and, if you ever wanted to do so, you can even flip the wood over without anything showing but wood.

 

[TwoTankAmin]

Early on I was more interested in doing planted community display tanks. So I used a lot of Cyprus. There was a gent in Mississippi or Missouri (I forget which) who collected from the swamps. His user name was swampwiz. The problem is the wood was very light weight. The way he made it sink was to drill a tile and use a stainless steel screw to attach it to the wood. The will would go under the substrate and asxt to weight the wood down by being on top of the tile. The problem with this is that is made it hard to put plants in the suvstrate where the roots would be blocked by the tile. And if one put the tile on top of the bottom glass it means burying the wood up to almost 3 inches in the substrate. I prefer to have all the wood showing

I found a way around this. I use nylon spacers of different lengths. The spacer is placed on top of the tile and the screw goes through the tile and then through the hollow spacer and into the wood. This meant the tile could sit on the bottom glass and the spacer would cause the wood to be elevated by the spacer so there was enough substrate above the tile to permit normal planting.