Ask an Expert

Ask an Expert

Joinery, cabinetwork & furniture

Like to know what wood to use building a pergola or framing a barn? How about the difference between tung oil and polyurethane as a floor finish? How to revive decking or deal with merbau stains? Or how to meet the building code or bushfire standards? Or ask about the environmental advantages of wood or forest certification?

Q. I need some advice regarding removing water staining to some western red cedar door frames currently under construction (they are new doors). Would appreciate some technical advice regarding method of repair and products available, and whether the doors would be able to repaired to an acceptable industry standard.

The usual recommendation for removing stains is to apply oxalic acid or (more conveniently) a proprietary wood cleaning product that contains oxalic acid. There are many such products on the market, produced by the major manufacturers of paints and wood stains. It's very important to follow the directions on the label, including washing off any residue after treatment as these products can bleach the wood if left in contact for too long. I'm afraid we can't tell you whether this will completely restore the doors, but it's certainly worth a try.

Q. I am making windsor chairs and wish to steam bend the top arch, the arm bend and the crinolin streacher. I want to make them out of Australian wood and want to know the best timber to make these pieces which will be appox 25mm x 25mm x 1500.

The most important quality for steam bending is to ensure that the stock is straight-grained. Any seasoning checks or surface cracks in the wood will indicate the grain direction, or failing that, drawing a sharp pointed tool along the surface will show which way the grain goes. Even with straight grain some species are better than others for steam bending. Actually radiata pine is rated quite highly as long as it is "clear" (knot-free) material. Tasmanian myrtle is also rated as excellent for steam bending according to a CSIRO Trade Circular in our library.

Q. I have a timber table and have had it covered for a few years now with a thick clear plastic. Recently, we took it off, and noticed the stain on the tabletop has become 'splotchy', and can't be cleaned off. How can I repair this damage? Would I need to sand it back and re-stain the whole thing? Or is there a way to get rid of the splotchy-ness?

It's hard to know exactly what's going on with your table. If the "splotchy-ness" was caused by heat (hot plates etc.), and there are white marks on the table, they can be removed by applying a hot iron over a damp cloth. It sounds unlikely but we've tried it and it works! However, if moisture has got under the plastic and made the stain blotchy the hot iron won't work. In that case we think you might need to sand the top back and re-stain and seal it. Before you do that it might be worth talking to a furniture restorer in your area to see whether there is an easier way, or whether some professional help is warranted.

Q. Hi there, I want to have a wood extension table made, to my own design to fit a difficult space. Because it needs to be 'moved in' to bench seating on 2 sides, it needs to be as light as possible. Yet strong. I want the table to be stained in a Wenge colour or even Japan blacked so the grain is not important. Can you please advise the best timbers for this job please. Many thanks, Angela Dale Surry Hills Sydney.

You would preferably want a like timber that takes stain well and is like pale in colour.  The most suitable examples would be Victorian ash (density 650 kg/m3) or Radiata Pine (550 kg/m3)

Q. I am hoping you can help me, my daughter is building a unit for her HSC project, and she wants to build the legs in a semi circle design, but she wanted to curve the timber, but knows this would be extremely difficult, she also wants a timber finish with a grain on the top, what type of timber would you suggest for this sort of design, she is putting a drawer in the middle. We need to purchase the timber for the project asap and I have no idea who to purchase it from in sydney or what type of timber she should use. It will be 1350mm in length and have a height of 1100mm, the legs are two half circles together with a small drawer in the middle, it is a beautiful piece of furniture, but she wants a beautiful timber for this, please help.

Bending timber is a very specialised skill. Traditionally it is done by steaming it, which softens the wood and makes it more pliable. However, this is not something an HSC student would be expected to do. A simpler way of making up a curved piece is to take several thinner pieces that will bend easily and glue them together in a curved shape. When the glue dries, the curved shape is retained. Regarding purchasing the timber, it is essential to use kiln-dried material, sometimes described as "seasoned". If you look up Timber Merchants in the Yellow Pages (or Google "timber merchants Sydney") you will find some suppliers. They should be able to recommend suitable types of timber from whatever they have in stock. Alternatively your daughter could consider using particleboard with a suitable decorative veneer for the top - this might be a more economical option and easier to obtain.

Q. I'm looking to buy an antique/vintage bookcase/display cabinet for my daughter's new house. An item I'm looking at states that it has a lovely "walnut veneer". Please can you tell me when wood veneers were first used? I thought they came in in the 1960's ? (I'm 68!!) Your help much appreciated.

Wood veneers have been used for many years, not just since the 1960's. Much of the antique furniture produced in Europe in past centuries was veneered, although the veneers were thicker than they are today. Until the 20th century saw-cutting was the only way to produce veneers so they were usually around 3 mm thick, whereas today's technique of slicing or peeling produces veneers of 0.7 mm. So the fact that a veneered bookcase is described as an "antique" could well be correct. As to when veneers were first used, they actually go back to ancient Egyptian times with veneered items such as furniture and sarcophagi found in the pyramids.

Q. I sell window furnishings and am looking at introducing timber plantation shutters into my range of products. whilst having sales reps from various companies come through my office, I have heard 2 trains of thought. (1) - tells me that they have a great product because it has no finger joints; the other (2) tells me that they have finger joints, and the way the finger joints are assembled (cross sectionally) makes their product stronger than those with no finger joints as this joining of the timber grains at differing angles makes it less able to warp and twist. Shutters, being on the window and exposed to different extremes in temperature. Can I have your opinion on this please?

We are inclined to agree with the person who says finger-jointing improves stability, because any spiral grain or sloping grain is randomised through the piece. Having said that, straight-grained, good quality timber that is properly kiln-dried is also stable, so there probably isn't much to choose between them. Occasionally, if finger-jointed timber changes moisture content and two joined pieces swell or shrink differently, the joint can show through. This could be a disadvantage, although perhaps unlikely if the timber is properly dried and sealed with a coating. So we suggest you look carefully at both companies' samples and make your choice taking into account the species of timber they use, cost and appearance.

Q. I’m looking to specify solid hardwood doors in several locations for a project we’re working on in Alice Springs. I’m considering Jarrah at the moment, with a simple low maintenance transparent coating to allow the natural grain and colour to show through. I’d like to know how to source the material and specify the product and finish.

Since the doors won’t be available off the shelf and will have to be made by a joinery shop, perhaps it would be best to work with a joiner familiar with local conditions, eg. Alice Springs Timber & Joinery. No doubt they have their own contacts for sourcing timber, but if not we can recommend Otto & Co in Adelaide as a supplier of specialty timber such as joinery quality jarrah. Otto & Co are also experienced in producing architectural joinery if you prefer.

In the dry Alice Springs climate it will be essential for the timber to have a moisture content not greater than 12%. You will also need to consider the quality of timber you require. To achieve more efficient use of our hardwood resource, specifiers are encouraged to consider “feature grade” material. This material may contain natural features such as tight gum veins, small tight knots up to 15mm, and borer holes up to 2mm which help to give the timber character. If these features are acceptable then Select Grade as specified in Australian Standard 2796.2, "Timber - Hardwood - Sawn and milled products, Part 2: Grade description", will be suitable. If not, you will need to specify accordingly by restricting these features beyond the limits in the Australian Standard.

Regarding finishes, decking oil or a similar product will achieve an attractive natural appearance, but regular maintenance is needed in areas directly exposed to the weather. However, oil is “low maintenance” in the sense that it is quick and easy to apply and doesn’t require any trade skills.

Q. Hoping you can help me please, I am in the process of buying new furniture for new home and have been looking at Australian Made Vic Ash etc but unfortunately far too expensive for my budget. I have seen furniture made from Malaysian Hardwood (rubber tree, I think was mentioned, not sure if that is correct). Evidently imported here and then stained once in Australia. I have not heard of this timber before, could you please advise me if any good (warping, mark easily etc) or am I wasting my money?

Rubberwood makes quite acceptable furniture and has a very similar hardness rating to Victorian ash, so there is little difference in wearing qualities. It will remain stable if the raw material from which the furniture is made has been correctly kiln dried. Perhaps your supplier has tested the moisture content of the stock and can advise you. Alternatively, ask how long the furniture has been in store - if it has been on the showroom floor for six months or so, that is long enough for any problems to show up. You should also check that items with a wide surface (eg. tabletops) have been correctly made. Tabletops should be attached to their base with table clips so they can accommodate some movement, not screwed or glued.

Q. I want to make a bed out of mallee timber and I was wondering if I can work it green or whether it has to dry first? Also the best way to finish it in order to preserve its natural look.

The name “mallee” covers a number of different eucalypt species, most of which are small trees. We weren’t sure whether your material was big enough to saw into sections or whether you intend to use it in the round. Either way it’s a good idea to dry it first. Some splitting is likely during the drying process, so when the timber is dry you can discard the split pieces and select the best for your bed. The idea is to slow down the drying process and there are various ways to do this. Some woodworkers coat the timber with wax, particularly the end-grain. Others pack it in sawdust. If the logs are large enough it is a good idea to cut away from the pith (centre of the log) as this region is more likely to split during drying. Regarding finishes, a satin grade polyurethane will maintain a natural look, and give you a surface that’s easy to clean.


Did you know?

In 2008 seventy percent of known old-growth trees are in nature conservation reserves.