If your child ever asks you “why do I have to take math? I will never use it.”, you can turn to them and say, “Well if you ever want to upholster a chair, then you need math.” Okay, odds are they probably won’t be reupholstering a chair but I can honestly say that making these channels sent me straight back to school with flashbacks of math class. Its not hard math but it is definitely math.
If you will remember back to the deconstruction phase of this reupholstering project, I was keeping everything I took off. And these channels are why. Cutting the finish fabric was step one. Unlike most patterns where you pin down the pattern and cut directly against the line, with reupholstering the pattern has already been trimmed, pulled and doesn’t give you the proper pull allowances. (You cut most of the pulls off when you are done.) So easy math number one (simple shape identification and addition) is looking at the center channel fabric and one of the outside channels to see if there is a noticeable 1/2 inch seam allowance. If so, as you cut out each channel, add two inches to the top and bottom for pulling on the center channels and add two inches to the top, bottom and outside edge of the outside channels. If not, then you add a 1/2 inch all the way around (to be safe).
In my case, I had a pretty distinguishable line for my seams. The biggest challenge in my case was the limited amount of finish fabric I had AND that it all had a specific way it needed to run. Everything had to run so that the nap of the material went all in one direction on the chair as it is assembled. Think of it as one big tetragram.
If I have not mentioned it before, I am not the biggest fan of sewing…these channels involve math AND sewing…what was I thinking again? Oh yeah, this was suppose to be fun (and it is, except for the sewing). So time to sew. It started by connecting each channel piece side by side with a half inch seam. Then bring on the extra strength thread and extra strong needle. Sew each seam together until you get one big panel of channels. Okay…I survived the sewing with a little help from my seamstress mom. (I’m not sure she would let me touch her machine…her other child.)
Now for the math. Again its simple but it involves thinking it through. The channels need a back to be attached to so they can be full and cushy. This lovely material is called decking. Without going into all the mathematical details, its a matter of determining how thick you want the channels, adding on three inch pulls on the outer sides on the top and the bottom, and measuring out evenly spaced top and bottom channels. The five inner channels need to match and the two outer channels add 3/8″ to each outer side (then the three inch pulls) on the top. The bottom is similar. The inner channels again need to match, then 1′ less on the outside (plus three inch pulls). The outside is a little more forgiving because you get to cut the excess fabric off.
So after all that head spinning math (I said simple not easy), it was about marking the decking with chalk to create sew lines. Chalk easily wipes off and doesn’t show through in the places it doesn’t. But the seam lines are important. Actually since I like puzzles and challenges, the next part was kind of fun. While holding the seamed line flat on the finish fabric, I lined up the seam with the corresponding chalk line and pinned them in place. I highly, highly, highly recommend that if you try this, have a big flat surface. Yes, I did get out of sewing it again. I love that my mom has an awesome sewing machine that she won’t let me touch and is willing to do my few sewing parts on this chair. (One welt cord is all I have left for sewing.)
Finished product is a panel with puffy empty channels waiting to be stuffed. But that’s for the next upholstery post.