Wood Sample Testing

Photo from left: White PVC board / Cypress / Hoop Pine / Cedar / Merbau / Redwood / Paulownia

Wood Sample Test Exposure to the elements

I thought i’d throw a few samples of different wood together for some weather exposure tests. Alex of Spicers Hollow Native Bees is trialing some Paulownia and donated a few left over samples and also some PVC board that some box makers use, the rest of the wood is just what i had laying around.

I regularly use Cypress and Hoop Pine so i already know what happens to them over time when used for bee boxes and exposed to the elements. I am more interested to see how the Paulownia holds up when exposed to full weather over time for appearances and what happens to it when exposed to high moisture in the garden.

This might help with how we make native bee boxes, for example if we just use clear coat for a nice timber finish, but then in a few months the box looks terrible, we may just have to use paint.

I made four sample boards,

  1. Placed in the garden where it might have a high chance of rotting
  2. Placed beside a bee hive, full weather exposed to some sun and rain
  3. As above, this one has a clear coating
  4. Placed in the shed, used to compare with the others

Update: 26/12/20203 months from the start

Thoughts so far: A very noticeable difference with the Paulownia. It’s a very light wood, seems very porous, absorbs moisture, starting to mould. Chances are that it might go perfectly well as Native Bee boxes if it’s painted . The bees will coat the inside with propolis so the wood may be sealed off.

All other samples of wood seem unchanged. The Merbau has leached it’s stain everywhere.

Below photo: 1. From Left – In the garden for rot test / 2. Uncoated / 3. Clear Coated / 4. Stored in shed

Update below: April 2021 – 7 Months from the start

All looks fairly well unchanged from the last check

Below photo: 1. From Left – Stored in the shed / 2. Clear Coated / 3. Uncoated / 4. In the garden for rot test

The Pond Test 11/01/2021

I saw a description for Paulownia that stated it doesn’t absorb water so I couldn’t resist. I placed Cypress, Hoop Pine and Paulownia in the pond.

After three days, I cut the end off each piece to check if any water had entered the end grain. The Cypress looks like the one that absorbed the least amount if you look at the long grain surface. Paulownia appears to have absorbed water, possibly in equal amounts to Hoop Pine.

Horizontal end grain image – cross section after being cut – Cypress / Hoop Pine / Paulownia

Above image 3 days in water. Below image 14 days in water.

Below: A little hard to see in a photo, the Cypress has taken on water faster and the piece of wood sunk. The Cypress is heavier to start with so would sink with less amount of water absorbed. It looks like the fibres/grain have drawn water further in to the wood and faster the the others . The Hoop Pine has taken on more water than the Paulownia, though both have drawn in a fair bit. It looks like the Paulownia may just have held water within the outside few millimetres and resists drawing water further in.

Horizontal end grain image – cross section after being cut – Cypress / Hoop Pine / Paulownia

Update: 15/04/2021: Three months from the start, the Paulownia sunk in the pond. The Cypress took 14 days and the Hoop Pine took two months to sink. Photo below shows the Paulownia on the right with a small dry area in the center.

A pretty impressive result for the Paulownia. It looks like the chaotic short fibres resist drawing water further in to the piece.

Horizontal end grain image – cross section after being cut – Cypress / Hoop Pine / Paulownia

Return for updates every few months

Check out the previous “Varnish and Oil Coating Test” article