Why wont my antique repairs stay stuck?

The arrival of two very different chairs this week, both with loose joints, highlighted this sticky problem and prompted me to write about it in greater depth. It was previously covered in part by another article; however it is such a common occurrence I thought it deserved to be dealt with more thoroughly.

All the joints of one of these two chairs had failed and were loose; they had been in this condition for some time and remained untouched, which was good. Because this made it a relatively easy job to dismantle, clean the joints, re-glue and smarten up with a little shellac and wax. Result, a happy client with a modest repair bill.

The other chair, owned by a very nice chap with a tube of glue, was quite a different matter. This also had failed joints, but in this case my well meaning client had squirted glue into and around every one of them. The back splat, had also received some of his attention after what looked like a nasty break, trouble was it had been glued-up with some small bits missing. If you have read my article on chair repair, you may think I’m starting to sound like a broken record. Well sorry about that, but this is the single most frustrating thing that I come up against on a regular basis, making tedious work for me and a large bill for my clients; and it’s just not necessary.

Most people do not understand what makes a bond; this is due to all kinds of wrong information that has been passed down through the ages. It started off as good advice, but like ‘Chinese whispers’ it gets changed a bit each time it’s repeated until it just ends up as nonsense. I can give you an instance of this, when much younger I remember being told that you should rough the wood of a joint to make sure the glue got a good hold. This little gem probably grew out of the fact that craftsmen laying traditional veneer would use a toothing plane (plane with a serrated blade) to score the surfaces of the timber being stuck. The real reason they did this was to flatten the two surfaces without the risk of tearout, always possible with a conventional plane especially when working on difficult timber. Although antique veneer is usually much thicker than the modern equivalent, faults like tearout if uncorrected would telegraph through to the surface. The tiny serrated teeth of the toothing plane are able to take multiple minuscule cuts much in the same way as sandpaper, but at a rapid rate of work. Today’s craftsmen mostly use a power sander, or if like me with one foot in the past, use either as the situation demands.

The people I really blame for most of this confusion are the glue manufacturers with their ‘’Bonds stronger than the wood itself’’ type of advertisements. This leads to the belief that there is some sort of integral strength in the glue itself, wrong. Things stick together when they are perfectly matched and have a surface that is perfectly smooth. Place two sheets of clean glass together and you will prove this for yourself. Theoretically if we could make perfect joints we wouldn’t need glue at all, but as we can’t we need the glue to take-up all the little imperfections and make the glued pieces feel like they are a perfect match and can’t bear to be apart.

You are probably at this point beginning to realise why so many repairs end up failing. As in the case of my glue toting client, whose chair joints hadn’t been dismantled and cleaned by washing the dirt, wax and dust of decades out of them. All this had been allowed to remain and get between the new glue and the timber, not to mention the old glue which would not be compatible with anything out of a tube.
The new glue just can’t work because it doesn’t get near the timber to iron out all those little imperfections. What it does do however, is cover the old hide glue that would easily wash off, with an impervious coat that later takes any amount of work to remove without doing damage to the timber.
Final note; There is absolutely no reason why you shouldn’t tackle your own repairs providing you abide by the golden rules. Never make a repair on a piece of antique furniture that can not at some later date be reversed. Hide glue is known to last centuries and can with the application of heat and humidity be reversed easily. If you do not have the equipment to use traditional hide glue you can find Franklins liquid hide glue in most good woodworker’s supplies.