ProVillage


Ecological – logging and sawing wood – Part III

Ecological – Part III (of VI)

Let us look at the different processes: Woodworking – Logging and sawing

The harvester cuts and debrances logs and the forwarder collects them according to thickness and lenght. Both have programmable computer programs.

The harvester, on the left. It cuts the tree, debranches it, sprays some urea on the stump, and paint-stripes on the end of the log.

The different colors on the ends of the logs, the paint-stripes, tell the forwarder-operator the length and sort of each tree.
The forwarder-operator can thus sort the logs by picking up one sort at a time.
The wagon of the forwarder can load about ten or more cbm [cubic meters] per time. The logs are taken to the nearest place where the log-trucks can be loaded.

In this video, the harvester cuts, debranches and debarks the logs:
http://www.youtube.com/watch?v=qYlBbLDL5dE

The debarking of the log has many positive aspects when logging in the warm season; the log is not so easily attacked by insects and fungi, the bark that remains in the forest will stay there as nutrients, the mass of the load is reduced by 7 – 8 %, the weight even more as the log dries much faster without bark.

Here you can see how a forwarder works:
http://www.youtube.com/watch?v=0EnO7f4Vxb8&feature=related

Both the harvester and the forwarder are computerized.

The univesity of Tampere (Finland) and a Finnish company developed a "Walking Harvester". The sawmill, the windmill, worked for 161 years, up to 1954, as a sawmill.

To the left is a “Walking Harvester
http://firrs.blogspot.com/2007/10/finnish-subsidiary-of-john-deere-has.html

The university of Tampere (Finland) and a Finnish company developed a “Walking Harvester” before John Deere bought the company. This harvester is meant for steep hillsides, where safety is very essential when logging in such an environment, and also the environment itself needs to be taken care of. If the earth is very scarred at steep hillsides, the heavy rain and fast melting snow can endanger the soil before nature has taken care of the “scars”. If the soil that keeps the trees growing runs down together with the water, it takes thousands of years to recover the forest – if ever.

The best known example of this are the former dense cedar-forests of Lebanon. First the Foinikians logged the main forests and after that, the Romans logged the rest. After the hills where barred, there was nothing that kept the soil in place.

There are different methods to keep the forests growing for centuries to come. The methods of logging, depends on if the forest is at a big lake or on steep hill. As a rule, forest are logged in zig-zag-corridors, so that the wind can’t get too strong, but blow mainly above the forest.

A roman sawmill that has been found in Asia minor, got its power from a water-stream. The band-saw to the right has the advantage, as all bandsaws has, that the kerf is smallest possible.

On the left, a Roman saw-mill found in Asia Minor.
On the right, a commercially made band-saw, Serra. The kerf (the gap that becomes saw-dust) is about 2 mm when you saw with a bandsaw.
A typical kerf for circular log-saws and frame-saws is 5 – 6 mm. It might seem to be a small difference, but the fact is that from one medium-size log, you can get one extra board. That makes a big difference at the end of the day – especially if the logs are of the highest quality such as knotless logs. The knotless boards, for example which the carpenters make boats from, do not come cheap.
The downside with a band-saw is that it is slower, but one thing which compensates this fact is that it uses much less electrical power.

A framesaw is typically operated with 7 or 9 blades. A circular saw can saw al og which but-end can be up to 60 cm in diameter.

The framesaw, to the left, has a set of fixed saw-blades, 5 – 11 blades. The framesaw through-saws the whole log into unsquared boards simultaneously.
The circular logsaw, saws fast, but only one board at time.

Laser techniques are used in many different types of processing units in a modern saw-mill.

Laser technology is used in many different types of processing units in a modern saw-mill.
Usually the saw-mill needs a big yard in order to keep the logistics in good order.

To be continued…

Bookmark and Share

Share this post!

add to del.icio.us    add to blinkslist    add to furl    digg this    add to ma.gnolia    stumble it!    add to simpy    seed the vine    add to reddit    add to fark    tailrank this    post to facebook



‘Ecological’ – What is that? – Part II

‘Ecological’ – the sustainability approach – Part II (of VI)

Well, there is no certain answer, but it all depends on many factors as told in Part I;

A chipboard factory uses a lot of energy. The release of formaldehyde from the particleboards are a great concern.
A chipboard factory

1) The chip-boards, or particleboards, are usually made from chips of some waste from some saw-mill or such. The glue is a combination of chemicals and the process of making chip-boards uses a lot of energy. The laminate is plastic. You maybe need to replace this kind of table-top every 25 years.
The release of formaldehyde from the particleboards is also a great concern.

2) To saw a stone into measure and to make the final product smooth and the edges round = a lot of energy needed. The durability of the stone can be hundreds of years, if the house does not burn or somebody smash it down with a hammer.

Saw-mills has often also kiln and drying facilities.
A saw-mill

3) To make it from hardwood by yourself:
a)
To buy a ready-glued sheet of hardwood, sawn into the dimensions needed. Then just sand the edges and such and coat it with something, or maybe just oil it. The coating has to be such that it will not give the food, or what ever you make on that table-top, any toxins. All sorts of lacquers or paint do not fit a kitchen. [To paint hardwood is a crime against humanity.]

If the logs are lying unbarked during summer, there is a great risk of mold, blue-stain and insect attacks.

The logs should not lay directly on the ground.
If the logs are lying unbarked during summer, there is
a great risk of mold, blue-stain and insect attacks.

b) You buy hardwood boards. The boards are sawn with some amount of energy. The planks are put into a kiln and dried in a chamber specially built for that purpose.
You can use different hardwoods, in order to get different colour-patterns, to suit your thoughts of architecture and design. You need water-resistant glue, but considerably less than is used in chip-boards. You need quite many tools in order to press the boards together, plain and sand them. Then you need to coat it. After 25 years, you might to need to sand your table-top and coat it again.


A table-top of birch for a desk, size 100 cm by 200 cm

c) You buy fresh hardwood boards directly from the saw-mill. Or as we aim to do; make the logging, then saw the logs with a DIY-band-sawmill. The logs are through-sawn – still not squared. [You can also square them before drying. They dry faster but tend to be curved sideways. We will write later about “How to square hardwood”]

Stacking non-squared boards on sticks in a shady place. The drying process takes 6 - 12 months when dried out-doors.
You stack the non-squared boards on sticks in a shady place. Depending on the thickness and what time of the year you have sawn the logs, the drying process takes 6 – 12 months when dried out-doors.

Planing birch

After that you have to square the boards and re-stack the boards inside a place which is constantly warm and dry. There the wood should dry for months, depending on the temperature. A minimum is about 4 – 9 months.

A stack of birch is opened and the first furniture components are selected for gluing the steps of the stairs that are under construction.

This can sound like a very time-consuming way to proceed, but after the first time, and when keeping the process continuous, you always have dry wood at your disposal. It is the cheapest and most energy efficient way to make any furniture.

The downside is that you need to buy a lot of tools and equipment to produce everything needed from scratch – from unsquared boards, that is. But to manage making different things from wood is a great hobby and very useful to learn and teach the kids.
Also teach your spouse, so that when you hear nagging about “we should buy this or that”, you can show where the tools are. Believe me; DIY makes wonders in a person’s personality. A silent spouse is something to have.

To be continued…

Bookmark and Share

Share this post!

add to del.icio.us add to blinkslist add to furl digg this add to ma.gnolia stumble it! add to simpy seed the vine add to reddit add to fark tailrank this post to facebook