dhoffer1 Posted March 2, 2011 Report Share Posted March 2, 2011 I have a set of 6 oak dining room chairs that have spindle legs with spindle cross braces between the legs. Some of the glue joints are loosening up where the legs join the seat and where the cross brace spindles join the legs. the problem I have is that not all of the joints are loose, only maybe half are. So my question is: "what is the best way to strengthen the joints?" should I try and disassemble the entire thing? if so how do I get the other joints apart? ***there are no screws or other hardware***. I appreciate any feedback or help that gets me to the end result I am looking for.... A set of stable chairs. I will try and remember to post some pictures tonight. Thanks, Doug Quote Link to comment Share on other sites More sharing options...
Pete Bennett Posted March 3, 2011 Report Share Posted March 3, 2011 I have a set of 6 oak dining room chairs that have spindle legs with spindle cross braces between the legs. Some of the glue joints are loosening up where the legs join the seat and where the cross brace spindles join the legs. the problem I have is that not all of the joints are loose, only maybe half are. So my question is: "what is the best way to strengthen the joints?" should I try and disassemble the entire thing? if so how do I get the other joints apart? ***there are no screws or other hardware***. I appreciate any feedback or help that gets me to the end result I am looking for.... A set of stable chairs. I will try and remember to post some pictures tonight. Thanks, Doug These type of chairs are traditionally glued using animal glue. The easiest way to check for that is to gently heat one of the joints with a hot air gun or better still if you have a sprung joint get a hot damp cloth and wrap around the tenon. If it goes gooey its probably animal glue. If it is there will no problem in releasing any or all the joints. One way to repair them and get a strong joint is a bit drastic but, if done right will certainly cure them. Take a joint apart, let's say a cross rail into a leg. Take an in canal gouge of slightly smaller diameter curve as the mortice and chisel an arc shaped fan shape into the mortice on the top side and another on the bottom side, maybe a 1/16" inch or so apiece. The effect is to have a kind of curved dovetail recess in the leg. Once you're happy with that, cut a slot in the tenon at right angles to the vertical, and form a thin wedge that should just fill the mortice dovetails when driven in. If you know what I mean by 'Fox Tail wedges' you'll get what I mean. The reason for cutting these in to the end grain rather than at the sides is to prevent, as much as possible, the tendency for the expanding tenon to split out the side of the legs. As for the tops of the legs they are normally through morticed in the seat. It is quite an easy matter to cut a slot in these mortices and drive a thin wedge in from the top once they are all in place. If, on the other hand your chair has been assembled using epoxy or a modern PVA you may have a lot more difficulty in disassembling the joints. Things then become much more involved. Having said that if they have been assembled using something like epoxy they are unlikely to have failed so easily in the first place. It is possible to drill through to meet the ends of the tenons and carefully make a notch in them, drive in a thin wedge to tighten the joints followed by a tight fitting plug to disguise the hole and re-finish almost invisibly but this does require a great deal more time and care. Let us know how you get on. If I think of anything else I'll post it. Pete Quote Link to comment Share on other sites More sharing options...
dhoffer1 Posted March 3, 2011 Author Report Share Posted March 3, 2011 Thanks for the quick reply, I am hoping to tackle one of the chairs this weekend and see how it goes. I will let you know of my progress and might even have a few questions before it is done. thanks, Doug Quote Link to comment Share on other sites More sharing options...
Bob Rozaieski Posted March 5, 2011 Report Share Posted March 5, 2011 These are factory made chairs from the mid to late 1900s. I'll just about gaurantee you that they were assembled with PVA glue. I've got a set of "Windsor" style chairs from the 50s and they have the same problem. In fact, all chairs that have this construction have the same problem. The issue is that the round mortise joint is basically all end grain, so it's a very weak glue bond. If you reglue these, they will eventually come apart again. To make them last a little longer, you need to get all of the old PVA glue off first so you have a wood to wood glue joint as you cannot reactivate PVA glue with more glue like you can with hide glue. To add to the problem, will remove a little bit of wood by removing the old PVA and therefore make the joint fit loose. So you will need to shim the tenon with a plane shaving to tighten it up. If you can get the entire chair apart without destroying it, remove the old PVA as carefully as you can. Scrapers work best for this on the tenon. The mortise is the challenging part. Use whatever you can to carefully remove the glue from the mortise and expose fresh wood. Then test the fit. Wrap plane shavings of different thickness around the tenon to get the fit tight again. Then use liquid or hot hide glue to glue the plane shaving to the tenon. When the plane shaving shims have dried, refit them to the tenons with a little sanding. Then use hot or liquid hide glue again to reassemble the chair. The hide glue is repairable, unlike PVA, so when the joint eventually fails again in the future, you can simply add more hide glue and the old glue will reactivate and redissolve into the new, so you won't need to remove the old glue again. Not so with PVA. Good luck! Quote Link to comment Share on other sites More sharing options...
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