I have a question for all you guys/girls with vast expereriance with furniture and general restoration of fine carpentry. Quite a few of our antique furniture items have (due to natural behavior of wood) have shrunk dimensionally loosening up the joints. Now I am aware that the armature fix would be clamps and reglue. My issue is with the more complex items, not the simple problems like loose chair legs. As an example our hall chair As a whole the chair is in great shape and does not need restoring but all the joints in the many pieces that compose this item have all developed a little shrinkage and thus as whole it loose. My question to the experts if regluing and clamping how would you deal with the interface between the mirrors (dimensionally stable) and the frames or the over all fit of the piece once all the shrinkage has been taken up? I may be over thinking this but any input would be appreciated.
OK, first of all there is no such thing as age related shrinkage. If the wood was dried correctly when the piece was made it was then basically stable. If it wasn't dried to the correct moisture content when made, the problems would have shown up very quickly as the wood reached it's equilibrium moisture content. After that, it will expand and contract with humidity but mainly across the grain. The shrinkage along the grain with humidity is unnoticeable. Most antiques were assembled with hide glue. It becomes brittle with age and general use causes it to break up. Also if the piece was stored in a very damp area it will also loosen up since hide glue is water soluble.
Now, the correct fix. To do this right the joints must be disassembled and cleaned. Leaving glue in the bottom of the joints may prevent the joint from being completely closed. As I said hide glue is water soluble, so water will help loosen any stubborn joints. Once all apart, clean all the joints. Reglue and clamp them. Don't' use any quick fix stuff, hot glue, or nails and screws, do it right. If you aren't comfortable doing this right, find a good furniture maker to repair them.
Pieces that come over from the UK or Europe in general can have a hard time adjusting to our climate which can be much drier. Plus stone floors on grade are common there, unheard-of here. The difference in humidity can cause a piece that has been stable for generations in a UK home to fall apart once it gets to the USA. If the rabbet for the mirror has shrunk so much that the mirror fits tight, it's necessary to remove some wood and make the mirror fit, just so that the shrinkage doesn't lead to splitting. Hopefully the joinery was done right, and the glue is just to keep it together. Casey
Absoutely Casey, there is a component of wood movement due to humidity. But not as significant as some people think. For example: If a 6" piece of cherry has reached EMC (equilibrium moisture content) in London and then moved to NYC it will experience about 7% change in EMC at the extremes. This 7% change in a 6" wide piece of cherry is equal to about 3/32 inch overall (some woods more, some less). So, the movement due to EMC does exist, but is relatively small and easy to take into account when constructing a piece. Although, I'm sure the when the old guys were making a future antique in London they weren't very worried about how it would behave in NYC. So, if a framed mirror is brought over from London and the frame becomes too tight for the glass here, it was probably constructed too small to begin with. I've had a lot of framed mirrors on antiques in my shop that were too tight, even though they were made in the good old USA.
Gents, (and all the other pro's)thanks for the insightfully advise, your freely giving of trade information and recommendations is truly appreciated (I'm sure by all). As this particular item is concerned we bought it at auction as a George Flint and Company(NY city). It was listed as circ 1890, and I have nor reason to dought the claim. when we bought it it was loose but not nearly as loose as it is now, in Calgary the air will suck the moisture from every thing in short order. Wanting to do right by the chair and have it last another 120 years I will put on the list as things to repair. Now I know the glue you guys would recommend is not plain old LePages yellow carpenters glue. To maintain the interety as an antique is there a trade substitute for good old fashioned hide glue?
No. Use hide glue again. It's important to keep it's integrity. In fact, hide glue is just a strong as any other modern wood glue. You don't need to go the route of having a glue pot. Tightbond makes a liquid hide glue and it works just fine.
Remember that the expansion is cumulative; if your cabinet has a pair of doors with 4" wide stiles, that is 16" of wood to expand, almost 1/4" according to your formula. My cherry bathroom cabinet (with 9" of total stile width) bears this out, as the normal 3/32 gaps for inset doors is not enough to make it through July without binding. Casey
Right Casey, but in WV you get about a 4% EMC swing, not the 7% I calculated moving from London to NYC. That 4% in flat sawn cherry equates to about .0127"/in of width. Which in the case of your bathroom cabinet equals about 1/8" total. Now all this is for unfinished cherry outdoors. Type of wood, finishes, indoor environmental conditions (a/c or not, type of heat, humidifiers, etc), and the cut of the wood (plain, quartered, rift), all contribute to the wood's stability or lack of.
In the case of the mirror that we discussed above, the total movement due to EMC across all the styles doesn't come into play because only the depth of the rabbet has an effect on the mirror. In this case if the rabbet is 1/2", the width of the style that will have an effect on the mirror will the 1", since the movement of the rail is negligible. So if the mirror frame is made out of unfinished cherry and is in WV, you are looking at .0127" that will affect the glass fit.
I beg to differ; I was dealing with dewpoints of negative 13 degrees this winter, drier than anything I've ever seen here. That kind of dry was sucking moisture out of the house faster than I could do to replace it. And, as I specified, it's a bathroom cabinet, so occasionally the humidity is high. In the summer the dewpoint will spend a week or two above 70 degrees. I'm not somewhere in the mountains of WV, btw. Eastern panhandle, 50 nautical miles from DC. USDA zone 6a. Casey
alfort wrote:No. Use hide glue again. It's important to keep it's integrity. In fact, hide glue is just a strong as any other modern wood glue. You don't need to go the route of having a glue pot. Tightbond makes a liquid hide glue and it works just fine.
I have to chime in here and tell you to listen to alfort! Never use anything but hide glue on antiques. Any other glue will cause a trip to a pro repair shop and a lot of scolding. Using wood glue or worse, gorilla glue, may even ruin it completely.
