Thread: Dining table top questions

Well today I got in contact with the last of the veneer specialists in the yellow pages (Veneercraft) who confirmed that they would not do a torsion box. I guess that is the end of the torsion box idea. I understand what Lignum is saying about going the vacsak -> homemade veneering table route but bearing in mind my current veneering skills, work committments and cost of multiple learning curve derived failures, I am still inclined to get the veneering commercially done. That puts me back to thinking about solid table tops. It is integral to the design that I am ripping off that the top be 50mm thick and have lines as clean as possible. A solid wrc top would be about 40kg which is tolerable, but the problem is having to veneer over natural timber with its expansion&contraction without doing a breadboard end (unnacceptable, remember the clean lines). My next thought was to obtain some poplar blockboard like this http://www.eco-core.com.au/2.1.html. Poplar blockboard is apparently extremely stable and quite suitable for veneering over - and there is no need to worry about e&c. I rang and asked price and was quoted $662 for one sheet !!! I am therefore thinking why not make something similar myself using recycled cedar ripped to size and glued with pva. Presumably all you need is three layers of poplar battens 12mm x (say)50mm x 1500mm, glued up like three-ply plywood, and 6mm mdf on top and bottom. Of course it is a lot of frigging around with the thicknesser and there are issues to overcome in keeping it all flat. But here is the question - If I make it up myself wont the individual timbers still be expanding and contracting, and as those forces combined across a wide area are extremely strong wont it tend to slowly delaminate? I guess it is the same question one might ask about the commercial blockboard. Clearly the
different layers are expanding and contracting independently, with each layer's expansion constrained by the different grain direction of the layers to which it is bonded. Is it the case that the expansive forces are simply suppressed by being so tightly bound to one or more other layers that cannot expand in the same direction? If so the whole thing relies on the integrity of the glue. If so then can the same thing be achieved using one layer of natural timber and two of mdf, rather then 3 of timber? Can this be achieved in the home workshop?

Anyone ever used this method of construction, or have any thoughts on these questions ?

Arron

Originally Posted by Lignum

And Steve mentioned joining veneer. It is surprisingly easy if you follow some standard procedures. Again ill give you a run down. But i dissagree that it isnt that hard with out a vacume. Its very fiddly and time consuming to do panells larger than a meter square with cauls or hammering. and get it right. But having said that its been a while and im spoilt by having vacuum power .

Hi Lignum,

I'd be VERY interested to hear about your methods for joining veneer - perhaps you could point me in the direction of some books / texts on the matter?

Cheers!

Steve i usually get the veneer in flitches around 20 odd per flitch and 280 - 310 mm in width. If im doing a table around 900 mm ill take the top four and use a lesser quality four (from a different flitch) for the bottom of the table. Ill lay the top four side by side and arrange to get the best match. I favor slip matching, most favor book matching. When iv got it right ill roughly match up the bottom four then place all eight on top of each other and masking tape it at the ends. ill aim for a 910 mm width so ill rip some 19 mm MDF to 228 mm and 60 mm longer than the finished top length. I then sandwich the veneer between the MDF and clamp together at the ends and three or four places along the middle. I'll then trim the execs veneer of with a chisel or knife. Then ill take it to the jointer (with the fence pushed right back) and joint the edges flush. This method works very well and you will get very good straight edges. Then to join them ill place the leaves on a table upside down and every 100 mm from the top stretch masking tape (blue 3m is by far the best) across the leaves bringing them together tight. When the four leaves are joined with help turn it over and use some veneer tape and apply to the top in the same position as the masking tape underneath. When the veneer tape has dried carefully flip it back over and remove the masking tape. You now have a lay-on that will have spot on joins that will be invisible