Adventures in Furniture Repairing

LeeBarker said:

Multiple office side chairs with inherent design flaws

It is unclear at this writing how many of these I will host, but there is a pile of them at the office, all out of commission. They were built by an unknown local cabinet shop. Almost all of them failed at the mortise and tenon joint at the front rail which supports the seat. The upholstery is in great shape, so the head guy at that office decided they were worth saving.

The inherent design flaw is just that-there's only that rail, no stretchers below. Nothing in the back failed, where there are three horizontal members.

Not much good can be said about the fit of the tenons in the mortise. But worse than that, the cabinet builder (who was definitely not a furniture maker) put nails in every joint. So part of the repair is figuring out how to get the dang things apart in the first place.

Having done four, I have landed on this procedure: drive the pin nails in as far as I can with a fine nail set, then use a spreading clamp to push the joints apart. The nails may come out in the tenon with the mortise intact. Where there is already a split along the grain line between the nails, I have taken to cutting that piece out and gluing it back in after the tenon is out.

I used name brand epoxy (not drug store variety) and wanted to load it with some walnut sawdust for color. I stumbled on an efficient way to get it. I put an 80x disk on my ROS and held it half on the walnut. The cuttings from the abrasive just fell off the disk and onto the table as it made the half revolution off the board.

Some images from the glueup:

Next: fabricate and install a second stretcher in the front of the chair. The epoxy takes 24 hours to cure, and I won't rush that.

Click to expand...

LeeBarker said:

Multiple office side chairs with inherent design flaws

It is unclear at this writing how many of these I will host, but there is a pile of them at the office, all out of commission. They were built by an unknown local cabinet shop. Almost all of them failed at the mortise and tenon joint at the front rail which supports the seat. The upholstery is in great shape, so the head guy at that office decided they were worth saving.

The inherent design flaw is just that-there's only that rail, no stretchers below. Nothing in the back failed, where there are three horizontal members.

Not much good can be said about the fit of the tenons in the mortise. But worse than that, the cabinet builder (who was definitely not a furniture maker) put nails in every joint. So part of the repair is figuring out how to get the dang things apart in the first place.

Having done four, I have landed on this procedure: drive the pin nails in as far as I can with a fine nail set, then use a spreading clamp to push the joints apart. The nails may come out in the tenon with the mortise intact. Where there is already a split along the grain line between the nails, I have taken to cutting that piece out and gluing it back in after the tenon is out.

I used name brand epoxy (not drug store variety) and wanted to load it with some walnut sawdust for color. I stumbled on an efficient way to get it. I put an 80x disk on my ROS and held it half on the walnut. The cuttings from the abrasive just fell off the disk and onto the table as it made the half revolution off the board.

Some images from the glueup:

Next: fabricate and install a second stretcher in the front of the chair. The epoxy takes 24 hours to cure, and I won't rush that.

Click to expand...

LeeBarker said:

Multiple office side chairs with inherent design flaws

It is unclear at this writing how many of these I will host, but there is a pile of them at the office, all out of commission. They were built by an unknown local cabinet shop. Almost all of them failed at the mortise and tenon joint at the front rail which supports the seat. The upholstery is in great shape, so the head guy at that office decided they were worth saving.

The inherent design flaw is just that-there's only that rail, no stretchers below. Nothing in the back failed, where there are three horizontal members.

Not much good can be said about the fit of the tenons in the mortise. But worse than that, the cabinet builder (who was definitely not a furniture maker) put nails in every joint. So part of the repair is figuring out how to get the dang things apart in the first place.

Having done four, I have landed on this procedure: drive the pin nails in as far as I can with a fine nail set, then use a spreading clamp to push the joints apart. The nails may come out in the tenon with the mortise intact. Where there is already a split along the grain line between the nails, I have taken to cutting that piece out and gluing it back in after the tenon is out.

I used name brand epoxy (not drug store variety) and wanted to load it with some walnut sawdust for color. I stumbled on an efficient way to get it. I put an 80x disk on my ROS and held it half on the walnut. The cuttings from the abrasive just fell off the disk and onto the table as it made the half revolution off the board.

Some images from the glueup:

Next: fabricate and install a second stretcher in the front of the chair. The epoxy takes 24 hours to cure, and I won't rush that.

Click to expand...

LeeBarker said:

Multiple office side chairs with inherent design flaws

It is unclear at this writing how many of these I will host, but there is a pile of them at the office, all out of commission. They were built by an unknown local cabinet shop. Almost all of them failed at the mortise and tenon joint at the front rail which supports the seat. The upholstery is in great shape, so the head guy at that office decided they were worth saving.

The inherent design flaw is just that-there's only that rail, no stretchers below. Nothing in the back failed, where there are three horizontal members.

Not much good can be said about the fit of the tenons in the mortise. But worse than that, the cabinet builder (who was definitely not a furniture maker) put nails in every joint. So part of the repair is figuring out how to get the dang things apart in the first place.

Having done four, I have landed on this procedure: drive the pin nails in as far as I can with a fine nail set, then use a spreading clamp to push the joints apart. The nails may come out in the tenon with the mortise intact. Where there is already a split along the grain line between the nails, I have taken to cutting that piece out and gluing it back in after the tenon is out.

I used name brand epoxy (not drug store variety) and wanted to load it with some walnut sawdust for color. I stumbled on an efficient way to get it. I put an 80x disk on my ROS and held it half on the walnut. The cuttings from the abrasive just fell off the disk and onto the table as it made the half revolution off the board.

Some images from the glueup:

Next: fabricate and install a second stretcher in the front of the chair. The epoxy takes 24 hours to cure, and I won't rush that.

Click to expand...

LeeBarker said:

Multiple office side chairs with inherent design flaws

It is unclear at this writing how many of these I will host, but there is a pile of them at the office, all out of commission. They were built by an unknown local cabinet shop. Almost all of them failed at the mortise and tenon joint at the front rail which supports the seat. The upholstery is in great shape, so the head guy at that office decided they were worth saving.

The inherent design flaw is just that-there's only that rail, no stretchers below. Nothing in the back failed, where there are three horizontal members.

Not much good can be said about the fit of the tenons in the mortise. But worse than that, the cabinet builder (who was definitely not a furniture maker) put nails in every joint. So part of the repair is figuring out how to get the dang things apart in the first place.

Having done four, I have landed on this procedure: drive the pin nails in as far as I can with a fine nail set, then use a spreading clamp to push the joints apart. The nails may come out in the tenon with the mortise intact. Where there is already a split along the grain line between the nails, I have taken to cutting that piece out and gluing it back in after the tenon is out.

I used name brand epoxy (not drug store variety) and wanted to load it with some walnut sawdust for color. I stumbled on an efficient way to get it. I put an 80x disk on my ROS and held it half on the walnut. The cuttings from the abrasive just fell off the disk and onto the table as it made the half revolution off the board.

Some images from the glueup:

Next: fabricate and install a second stretcher in the front of the chair. The epoxy takes 24 hours to cure, and I won't rush that.

Click to expand...

LeeBarker said:

Finished: Epoxied joints cleaned up, new rail installed, delivered!

Client is pleased.

The new stretcher is attached with three pocket screws per end. Each one was custom fit so it slid in without any undue stress on the old stretcher joint, all of which were reglued with epoxy.

The screw pockets were daubed with stain. It is possible to note them from a certain angle, but you have to be short in the torso or slumped down in your chair in order to do that. All in all, a successful repair.

One certain learning: in epoxying the M&T joints and the armrest-leg joint, I inserted ample epoxy and squoze the joint closed slowly, making sure there was no glue starvation. I promptly wiped off the squeezeout. After the mandatory 24 hours cure time, the glue was not always flush with the surfaces-it appeared to have receded. On one severely broken back leg joint, there was some wood missing and I filled that area with epoxy, which cured concave. I am wondering if this brand of epoxy has some shrinkage. I haven't experienced it before, but this is a new brand to me.

Also, the masking tape on the joints left residue only on the areas where there was epoxy on top. I wondered if there were some heat transfer there that cause the deposit of the material. It did not come off easily. The best solution was rubbing alcohol which cut the residue without disturbing the lacquer finish on the chairs.

On some chairs the new stretcher color did not match the seat rail, but on others it did-I noted that there was a wide range of colors on the various chair parts. I don't know if the parts were prestained pre assembly from differing batches of stain or if the material wasn't stirred as each chair was stained.

Onward!

Click to expand...