Material:Wood

From CoMakingSpace Wiki

Revision as of 06:10, 5 May 2023 by Lukas (talk | contribs) (→‎Wood Sources: typo)

MaterialInfoBox

Wood

Stack of wood.JPG
Synonyms: timber (unprocessed), lumber (boards etc.);
DE: Holz, Massivholz
On Site? a few scraps of varying kinds & sizes
Location: wood workshop
Suggested Tools: saws, router, wood drill bits, laser cutter,
CNC router, pyrography burner, planes,
rasps, files, sanders, sandpaper, ...
Contains: mainly cellulose and lignin
Similar (More or Less): engineered woods

Much like "plastic" and "metal", "wood" is a pretty broad term encompassing numerous different materials. Although they share many characteristics and can generally be shaped with the same tools, features like stability, grain and surface finish vary greatly between different kinds of wood.

Besides natural woods from different tree species that this page focuses on, there are engineered woods (DE: Holzwerkstoffe) with artificially enhanced advantages. Veneers can give such engineered woods the surface look of massive wood at first glance, and cut faces can be made more attractive by gluing on edge banding.

We usually have some scraps and reclaimed wood in store but you should expect to have to bring your own if you need large amounts or a specific variety.

Sustainability

Not only did the term sustainability (Nachhaltigkeit) originate from forest management [1], one should also try to act responsibly when working with wood as a material. Properly used, it can be one of our best options to stop using more resources than the planet can reproduce.

A few key points to keep in mind:

  • long life - for a negative carbon footprint, the wood from a tree should be in use longer than it took to grow the wood. Best examples are buildings and fine furniture that may last for generations!
  • responsible sourcing - regional, properly managed forests are always better than importing tropical wood. If you absolutely feel you need a certain species, please find a source of plantation wood to stop destructive logging in the rainforests!
  • minimize waste - whenever possible, find a use for the unavoidable scrap wood or share it with other Makers who may be able to make small projects without buying anything new!
  • recycle "old" wood - unless there are already woodworms at work or the wood received questionable chemical treatments, you may find great raw materials in old furniture that others have thrown away. Check out recycling stores or ask the previous owners for permission if you come across useful bulk trash (Sperrmüll) at the roadside!

Structure

Wood is an anisotropic material, i.e. its structure changes throughout a piece and with different directions. The reason for that is the grain (DE: Maserung), caused by the (more or less) parallel orientation of fibers in a growing tree.

There are also changes in density with growth rings (in non-tropical wood - denser wood being produced late in the year) and very dense knots where a branch used to sit.

"Reading" wood grain is an important skill to practice in the wood workshop, whether simply recognizing end grain that is bad for gluing and screwing or [analyzing the less obvious orientation of side grain for cutting operations.

Varieties

The list of woody plant species goes on for a while - here we collect some that have been used for woodworking in our community.

Wood is often separated into softwoods and hardwoods.

Hardwoods

Wood from broad-leaved trees (DE: Laubbäume) - harder due to (more or less) slower growth, therefore also more expensive than softwoods. Fast-growing trees like willows, poplars or birches produce much softer "hardwood" than others.

Softwoods

Wood from coniferous trees (DE: Nadelbäume) - fast growth, therefore commonly available at low prices with the downside of reduced strength and a much coarser grain. Again, not all softwoods are equally soft!

  • spruce (DE: Fichte) or fir (DE: Tanne) - often undistinguished and labeled "FI/TA" at the store
    • common construction beams

Marking

Pencils work great on wood, often used together with a square to obtain right angles.

Most woods are also easily scratched by a pricking awl or finer cutting tools such as marking knives: marking with a little cut (Anreißen) is the most precise it can get! DE video An additional advantage of this is the extra guidance you get for the hand saw or chisel you are going to use.

Shaping

The most common cutting tools for wood are handheld or powered saws. Using a router or woodworking chisels expands your threedimensional options.

We are also working on establishing CNC techniques such as CNC routing and laser cutting.

Sawing

As wood is fibrous, ripping it apart with the teeth of a blade can cause unsightly tearout/chipout/Ausriss. The splinters will always occur on the side where your blade exits the workpiece. There are a few precautions you can take against this effect though:

  • zero clearance boards
    • e.g. as insert on a table saw or little plastic square on a jigsaw
    • leave no room for the wood to "escape" the blade
  • adhesive tape along the cut line
    • please let us know which ones work well!
  • working from the proper side of your workpiece in case the other one won't be seen anyway

Holes and Recesses

Use wood drill bits for round holes and recesses (Vertiefungen) and a router or chisels for custom shapes, e.g. mortises.

With hole saws or a jigsaw you can cut holes, but not recesses.

Chamfering

"Breaking" sharp edges by cutting a chamfer (Fase) can have a great aesthetic effect and may improve your product's handling.

Common tools for chamfering (Anfasen) include planes, rasps or files, chisels and coarse sandpaper. A router with an appropriate bit or a bow sander help you achieve edges that are rounded over.

Steam Bending

Wood can be forced into a curved shape under exposure to heat and moisture (steam!), but this is something we do not have experimented with so far. Especially beech and birch are suitable for bending. [2]

Bent Lamination

Thin strips of wood are pretty flexible along their grain direction and can be brought into many interesting shapes like spirals or the belly of a boat if you glue them together in the desired position - you'll basically end up with custom plywood!

Gluing

Wood is commonly glued with wood glue but other adhesives may be needed when trying to glue other materials to wood.

Finishing

Sanding

Common grit sizes for sanding wood are 80, 120, 150 and 220. Check out this sanding basics video tutorial.

You may want to consider raising the grain before the last sanding pass if you are going to apply a water-based stain in the end.

Polishing

Very fine sandpaper grits and special polishing pads can make wood extremely smooth.

Planing

Some woodworkers don't use sandpaper at all but produce silky smooth surfaces with nothing but hand planes!

Oiling/Waxing

To preserve or refresh the shine of a polished piece of wood, oil or wax can be rubbed into the surface. We do not have a lot of experience with these finishes yet.

Burning

You can try adding dark accents to your workpiece with a pyrography burner, laser cutter, hot air or even open flames! Do leave some actual wood behind, not just charcoal ;-)

Intense burning can also be used to shape wood or seal its surface against harmful environment conditions.

Sourcing

Buying Rough-Sawn Wood

With our jointer-planer, you are able to buy rough-sawn wood from wholesalers, your favorite construction market - or even directly from one of the saw mills in the surrounding area. Depending on how rough the wood is, you'll have to plan on removing between 2 and 4mm of material per large face and up to 10mm on the smaller faces of the wood - this is due to the sawing marks on the larger faces and on the often non-squarely cut smaller faces. In construction markets, the rough wood tends to be on the lower end of the amount of material to be removed, while wholesalers or mills tend to be on the upper end of material to be removed. So, you should buy your base wood oversized and rather too large than too small.

While construction markets like Bauhaus, Hornbach or Obi usually have fixed prices depending on cut and size and are rather expensive, wholesalers and saw mills price their wood by volume and are often open for negotiation - you usually directly get 3% off when paying immediately, if you ask. Always ask beforehand whether the volume is calculated *before* drying (which is often the case for domestic woods) or *after* drying (which is often the case for imported wood) - this may change the price by up to 15%.

Buying Wholesale or at a Saw Mill

You should bring a yardstick and (optionally) a small hand plane.

If you want the best bargain, you should also check whether the wood has been Air Dried (noted by the abbreviation AD) or Kiln Dried (abbreviated by KD) - the former is usually 10-20% cheaper than the latter. Air dried wood has gotten a lot longer time to dry out, which also reduces the internal stress - air-dried wood tends not to warp and rip as much as kiln-dried wood, but both are completely fine to buy.

When choosing woods, it's customary for you to choose the exact pieces you want, which you usually have to buy whole. You usually are allowed to bring a small plane and can ask to plane a small area to check the grain. Also bring a yardstick to determine the sizes, since each piece will have its own size. Should the wood have a split at the end, this piece has to be cut or will continue to rip apart later on. It's okay to not take that board or negotiate a lower price.

Wood ring direction.png (Source)

You should also check the end face and identify the cut - especially if you plan to use the wood outside, where the environment will cause the wood to shrink and expand.

  • if the wood grain lies flat, the board tends to warp uniformly and a lot (fig a)
  • if the wood grain stands (fig b), the board will not warp
  • if the wood grain is diagonally (fig c), the board tends to warp unpredictably, but not as much as in figure a

If you've chosen your boards, an employee of the wholesaler or saw mill will calculate the price, which you usually have to pay now. They usually will shorten the boards roughly with a chainsaw (transport cuts) to fit them in your vehicle.

Time and Effort / Cost

Depending on the hardness of your wood, you can take off more or less depth in one pass on the jointer or planer. To give you a rough idea: Lars bought 12 pieces à 1000x300x55mm of rough sawn hardwood from a wholesaler. It took 2 hours to get the 12 pieces flat and square on 3 sides and reduced the width of the boards to 49mm and another 20 minutes to get them to their final thickness of 45mm. Add another 15 minutes for cleanup of the machine. This produced 2 sacks of saw dust.

If the wood would have been a softwood from a construction market, the first part would have taken around 1 hour instead of 2 hours. Still, in contrast to hand planing with a bench plane, it's probably a fifth of the time needed otherwise.

Some saw mills might also joint and plane this for you, which is a service you'll obviously have to pay extra for. Still, in comparison to buying pre-planed and joined hardwood, it's a lot cheaper to do it yourself. Remember: Jointing and planing dulls the knifes of the machine a lot and the saw dust has to be recycled - your member fee does not include those costs, so remember to leave a share.

Wood Sources

  • local hardware stores:
    • Bauhaus in Eppelheimer Straße, just down the road from us
    • Hornbach in HD-Wieblingen, just across the railroad tracks from us
    • OBI in HD-Rohrbach Süd


Paint and Chemicals for Wood

  • hardware stores (see above)
  • Baufix in HD-Rohrbach Süd

Further Reading

  • The Wood Database with information on pretty much every species you can imagine
    • e.g. hardness, shrinkage, identification, project suitability
  • DE: Holzarten-ABC vom Fachverband deutscher Holzhändler
    • Materialkunde so gut wie aller Holzarten, mit Verarbeitungshinweisen, Austauschhölzern u. v. m.
Retrieved from "https://wiki.comakingspace.de/index.php?title=Material:Wood&oldid=13989"