Expert: Mark H. Miller - 6/10/2008

Question
QUESTION: Hi Mark,
 I'm making my own dining room chairs and am working on my second prototype but I've been putting off what to do with the back. I need some help with the chair back design so that it can be upholstered.  In particular, what kind of frame do I need?  Should it be removable?  If so, how is it attached to the legs after it's upholstered?

I think a description of the chair will help you understand the question. The chair design is contemporary with a common continuous back-leg arc.  From the side view the leg profile is thickest at the seat and then tapers to approximately 1" at the top and bottom.  I want the back to fit between the legs, starting about 3 inches above the seat and extending about 2" above the top of the leg. I also want the back to have some thickness so that it is thicker than the leg when viewed from the side.  I feel it may have to follow the leg curve somewhat, if not exactly, and may need to taper near the top so as not to look to heavy.

By the way, the seat will be a slip seat with 2" of HR foam (from your earlier answers, thank you).  My plan is to have an upholsterer do all the upholstering so I'm also interested in finding one. I saw the recommendations you gave back in 2006.  I haven't checked if they are still in business. I live in San Jose, so one closer would be helpful.  Thanks, Andrew


P.S. One frame idea I had envisioned was placing a 2x4" on edge at the bottom and a 1x4" on edge at the top with say 1/2" plywood on each side.  The plywood would be cut to work with the side profile of the chair leg.  I didn't know if this needed any additional horizontal pieces for support and comfort.  And more importantly, if this frame needed to be removed for upholstering, how would it attached to the legs once it was upholstered?


ANSWER: Hi,

Without seeing the chair itself the question is a little difficult to answer, however, from what you write in you "P.S." that is in my opinion exactly the way to go with these suggestions, make certain that the 2X4 at the bottom is a good quality wood, and rather than using plywood for the sides use a similar wood as the top and bottom braces and out of that you carve a piece that tapers from 2" at the bottom to the 1" at the top while following the side profile of the chair.

You should not need any additional bracing after that.  The side pieces should be glued and screwed into the chairs vertical posts.   The top and bottom pieces should have glue and dowels.

I do not know of any upholsterers on the peninsula, I would also recommend that you contact one of the upholsterers that you may choose to work with and take them the prototype before you produce the final product.  There is a bigger issue which is how you want the upholstery fabric to bud up to the exposed wood of the vertical chair posts, that design determines how you build the frame,  will it be gimp/braid, single welt or double welt or nothing, the final look you want determines how you construct the frame for the back.

I hope this helps.

Mark Miller.



---------- FOLLOW-UP ----------

QUESTION: Hi Mark,

Thank you for your quick answer and for your suggestions.  It's a relief to know I was on the right track.  Knowing the back frame doesn't have to be removed is a big help.  I had thought of a number of not simple ways to make the back removable, none of which I felt confident would really work.  I ideally would like the fabric to not have any braid or welt where it meets the exposed chair posts and thus assumed the only way to do this would be to make the back removable.

Since I could not attach a picture of my chair design, I uploaded a couple of my sketches I did for my first prototype.  If you copy and paste the following URL into your browser it should take you to them.

         http://picasaweb.google.com/folkdancers/DiningChairs

There is also a front view sketch of the chair back frame.  I'd appreciate letting me know if any of your suggestions should be modified after looking at these.

   One additional follow-up question is in your reference to the wood for the back frame.  You suggested these be of "good quality wood" and I assume that means knot free.  Should this wood be a hardwood or a softer wood?  You mentioned using brads to adhere the fabric to the wood so I wonder if soft wood would be better. As an upholsterer, which kind of wood would be preferred?

Thanks again,
   Andrew

Answer
Hi,

I saw the sketches of your chair.

To make the back without any welting or braid along the sides you would build the exact same frame for the back as if it were permanently mounted between the two back posts except that you do not attach the back, leave that for the upholsterer.  Exactly as you wrote.  

The upholsterer covers the front and sides of the back frame and then screws the back into place into the two back posts with counter sunk screws that are placed on the inside of the two vertical back posts, 3 on each side is enough.  The upholsterer then puts the fabric over the back of the chair - also called the "outside back" and closes the whole thing,  doing it that way you would have a plain back without any trim along the sides.  The amount of labor involved in is almost the same no matter which way you choose to go, it's only a matter of the look you want.

The chair frame as a whole unit will be stronger with the back permanently glued in place but that should not be a concern.

It may look nice to put a welting or incorrectly called "piping" around the perimeter of the outside back, if you did that there is usually also a welt along the perimeter of the seat bottom.

The wood that upholsterers prefer is Alder - small knots are o.k.  When you said a 2X4 I hoped you were not planning on using fir.

You have asked very good questions and should do just fine, leave no more than 1/8 inch space between the two back posts and the back frame, just enough for two layers of upholstery fabric.

I hope this helps.

Mark Miller.