So, with a kid-free weekend looming (HAH! symbolism, here!) in my very near future, let's play a game, shall we? It's called "How do I figure the yarn requirements for my next project?"
Non-weavers, beware. You might just wanna skip this one, OK? Because it involves math. Not hard math - but still. (And we're playing this game as a safety measure, in case a)I forget my calculation sheet on my desk at work; b) my dial-up at home bogs down (again) and I can't download the XL file I set up to calculate it for me; or c) both of the above. I, personally, am betting on c. *g*
So, I want to weave some dishtowels. I've wanted to for a while, but the pink nasty thing has been hogging the loom. It'll be off - FOR SURE - tonight. I'll be able to warp with finer threads now, since the kidlets will be elsewhere. Let's figure out what I need to do:
I will be using a 4/2 cotton for both the warp and the weft. I have *tons* of this stuff, not sure of the quality since it's been sitting a while, but, there it is. If I find it too nasty to work with, I'll re-do these using the 8/2 that I have - I have 4 *huge* cones of it. But, for now, 4/2. It wrapped up at 22 wraps per inch (WPI). I'm planning on a twill weave - you sett that at approx. 2/3 the WPI, so....approx. 15 threads per inch.(Written as E(nds)PI) (Plain weave is sett at 1/2, so that would be 11 EPI) Still with me?
I want to end up with 8 towels, with a finished width (I think...I've played around with rulers today) of 12" and a finished (hemmed) length of 18". I'm figuring I need to add about 1" on the end of each towel for hemming purposes (I prefer to over-estimate, if that seems extreme to you), so..that means 20" per towel in length.
Now, if I measured out 12" of warp, and started weaving, I'd be disappointed - the weft thread will pull the edge threads closer together (called draw-in). So, let's figure...ummm...estimating since I haven't, in fact, used this particular yarn before....on 1 inch for draw-in. I also need to account for shrinkage....again, I'll estimate at 15% (I got these estimates from Deb Chandler's Learn to Weave book, YMMV). So, doing the math:
12 + 1 + 2 = 15 inches in the reed (or on the loom).
*As an aside, I don't care if they end up a little wider then I want. That'll be great!*
Ok, we have the width figured out. Multiply that by the EPI number, and we have 225, the number of ends I need to measure out. But, how many do I need? (See, more math!)
I want to end up with 8 towels, finished out at 18" each. We added 2", so that's 20" each I need to weave. So, 20" X 8 = 160". (Don't worry, we'll convert it to yards in a minute). I need to add approx. 15% to cover take-up, the amount of length "eaten" by the threads moving from bottom to top of the fabric. This figures out to be 3". I also need to figure shrinkage (I figure it'll shrink the same lengthwise as it will widthwise..hopefully it won't be more)....that figures at 24" on the whole 160". Now, we also have to figure in "loom waste", the yarn at the beginning and end of the warp that you can't weave off - where you tie on in front and back, and what can't make it thru the harnesses because of the knots in back. I'm being generous - I'd rather be surprised and get another towel or a washcloth out of the warp instead of not getting the 8 I planned for, so I'll say 24" of waste.
So, we have:
160 + 3 + 24 + 24 = 211 inches of warp. Divide by 36, and we get 6 yards of warp.
So, I need 225 pieces of yarn at 6 yards each. Somewhere around 1300 yards total (OK, so it's 1350....*g*)
Figuring the weft is similar (thanks to C and D who gave me some calculations!), but you don't need to include draw-in or waste. I figured it up, but I don't think the numbers are right - it says I only need 161 yards for the weft, and that just doesn't seem right. I figured 16.5" per shot, at 15 PPI (picks (shots) per inch), which = 31.5" of weft to weave 1 inch of fabric. Figure 184" total to be woven (the total length of all 8 towels + the shrinkage)...and it comes to 5,796" of yarn, or 161 yards.
I just can't quite see that....I've got plenty of yarn, though, so it doesn't matter - in *this* project. If I was spinning for it, though, I'd want to make sure the numbers were right so I wouldn't run out of yarn in the middle of the project.
The only decision left is what color? It'll definately have a tan involved, since I have 6 or 7 cones of tan, but do I want to warp stripes? Solid color warp crossed with different weft? Striped weft? Plaids? Fancy twill or plain?
That's what I love about weaving - you can do so many different things on 1 warp!
Now, a confession - I don't normally do the whole huge calcs I did here. Normally, I decide to do 1 thing - a scarf, say. I figure a width, figure the WPI, get the EPI from those 2 numbers, add another inch, then say "2.5 yards will be plenty for this! I'll end up with at least 2 yards when I'm done." and run with it. Since this, however, is a bit more involved, I wanted to do the whole thing.
Did I put you to sleep? *g*