Friday, July 13, 2012

How to dress salvaged timber.( Recycled Jarrah Cabinet, Part 2)

I am building a nice big custom cabinet, using predominantly recycled jarrah. This post is the second part to telling the story of this build and the techniques used along the way.

To make high quality furniture and joinery, you need material which is flat and straight. Recycling salvaged timber involves a fair bit of machining work to convert these sticks to the flat and true state.
Most of this timber has been seasoned in situ. The houses were built with green construction timbers, as it is much easier to work despite being heavier, and over the years the timber seasoned while nailed in place in the structure of the building. Therefore it can be cupped, bowed, with wind, with spring, and peppered with nails! It is also very dry and hard. It just needs to be dressed so that we can utilise this resource in the best way possible.

Dimensions Matter.
In keeping with an earlier era, much of this piece of furniture will be a predominantly finished at 22mm thick (7/8"). This was a very common material thickness in the past. In the modern era this has been reduced to 19mm (3/4") which just doesn't quite cut the mustard. It's like the difference between a bevelled edged mirror and a flat mirror ... there is no comparison in the look and sense of quality of the piece.

Not the best picture, but a nice load of 8"x2" sticks needing to be dressed.

How to dress timber which is too big for your buzzer.
I have a small workshop, and my machinery includes a beautiful old cast iron 6" Woodfast Buzzer and a modern Taiwanese 15" Thicknesser.  Buzzer? I think that's an Australian term. To you bods in North America and Europe, read "planer". Thicknesser? Again, this can be translated to "thickness planer".
If you put a twisted stick through a thicknesser, you just get a thinner twisted stick coming out the other end. Therefore the normal machining process involves flattening a face and straightening and squaring an adjoining edge over the buzzer and then creating faces parallel to these using the thicknesser. You can't effectively flatten an 8" board over a 6" buzzer, but once a flat face is created it can be easily put through a 15" thicknesser. This post describes how to get around the problem of the buzzer being too small for the material being used!

Preparing the timber.
OK, lets start from the beginning, with a pile of dirty used timber, probably containing nails, etc. What wonderful potential there is, waiting to be unlocked, and used to create a beautiful piece of furniture, a future heirloom. This stuff in the pile is all jarrah. I reckon this is one of the most versatile and beautiful hardwood timbers on the planet - though I could be accused of bias!
The process is as follows:

1. Elevate the boards onto a pair of saw horses or some other surface. It's good to save your back from some grief, so make it easier for your body.

2. Scrub each surface with a wire brush. Cleaning out decades of accumulated dust and grit from the surface will be easier on the knives in your machinery. The grit dulls them prematurely. While doing this, you will also be doing a visual check on the material - particularly looking for nasty embedded nails, screws, and other unfriendly surprises for your buzzer and thicknesser knives. These metal foreign bodies will need to be removed.
A quality wire brush brush helps remove grit and dirt from between the surface fibres.

3. Scan the boards carefully with a metal detector. The visual check can miss a lot of metal, so the wood recycler's best friend is a metal detector. Just remember that the metal detector will also pick up the screws in your saw horses! You get the knack of using these things pretty quickly. After the visual check and sweeping the material with a metal detector, if you hit a nail with your machinery it's all down to human error! ... your human error. It is a bummer when it happens. I've done it more than once, unfortunately. Try not to take short cuts with the preparation.

A cheap metal detector can save you a lot of money in machine knife re-grinding!

4. Remove any nails and metal hardware. Once you have identified any metal foreign bodies either by eye or by metal detector, these will  need to be removed. If the nail is still hanging out, a claw hammer or pinch bar may simply remove it. However there are times the object is below the surface, leaving nothing to grip. To remove these, here is the process:
Ya gotta go, nasty nail! ... but it's buried below the surface, and needs extracting.
Use a chisel to create access below the head - enough for the pincers to be able to grip it. 
It's looking like a winner! Out ya come!
It's not very big, but it would've done a lot of damage to the thicknesser knives. 

5. Create a flat face. A pair of winding sticks (two pieces of wood used to check for "wind") are important here. By sighting across the top edges of the winding sticks, which have been placed across the board at intervals, we can see how out of parallel the sticks are.
A pair of winding sticks in action.
Planing of the surface is undertaken wherever necessary in order to create a flat surface. This is achieved when the winding sticks sight for parallel consistently, when one is placed across an end and the other is places across the board anywhere along its length.
Straightedge in use to check lengthwise flatness.
The use of a long straightedge assists in checking that the surface is also flat along its length. Additional planing is used where necessary to ensure the surface is straight along its length.
It's a beast... heavy as lead, which is an advantage. The 25 year old Makita planer.
On small boards, this flattening process is easily done using a jack plane - like my trusty No.5 1/2. However, in this situation, with a pile of very hard jarrah boards 8" wide and up to 11 feet long, my nice heavy old Makita electric plane is a life saver, with a block plane for fine tuning of the surface.
Now that's looking pretty good. The winding sticks don't lie.

Dressing the boards through the thicknesser.  The whole idea is that the flattened surface goes down on the machine table. The cutter block then removes material from the top side. The board is passed through the machine until the surface on the top side is flat enough to flip the board over and machine the original flattened surface. This passing and flipping continues until both surfaces are dressed and the desired thickness is obtained. (Sorry, no pics of the machining process here.)


Two beautiful flattened and dressed boards emerge from the thicknesser at 25mm thick.
The buzzer and table saw are next used to straighten and parallel dress the board edges.
Salvaged jarrah commonly has the most amazing colours in it! Yum.

From previously twisted sticks we have now created dressed and beautifully flat boards.
That was the whole idea, wasn't it?
... Now I can get on with making this cabinet.

4 comments:

  1. Amazing!!Thank you for sharing this experience and the useful advice! :)

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  2. Wow, you improved the look and shine of that wood so well! I can't believe you got it looking that nice. We have a bunch of wood that could be refinished like this. Thanks for sharing these pictures and instructions!
    Celine | http://www.bearslashing.com

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  3. Hello Greg, I am renovating an old house with beautiful (19mm) Jarrah floors, I am having difficulty finding nosing for the split level living room. Do you know of anybody that could make them for me. For some reason suppliers don't sell 19mm step nosing anymore in Perth.
    Regards
    David


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