Beater Blues: Getting Consistent PPI

Dear Madelyn,

I am weaving with 10/2 mercerized cotton—two projects on two looms. One is 46” wide, the other is 10” wide. They are both set at 24 EPI. On the 10” wide project the PPI is 24. On the 46” wide project, the best I can get is 16 PPI. Why am I not able to achieve the same PPI? And what should I do to correct for a more appropriate PPI on the wider project?

Thank you,

––Charmaine Cunningham


Hi Charmaine!

When I was in high school, I loved physics and thought I wanted to be a physicist. One year of college physics told me: "Find another career!" But I love some of what I learned in high school. When you hit the fell of the cloth with the beater, you are applying force. Force equals mass times acceleration. That means that the weight of the beater and the speed with which it moves all affect the cloth it hits. With a wider warp, the mass of the beater is much less in relation to the cloth it is hitting. Usually, too, the more warp threads you have, the more friction there is to slow the beater down. So it’s the wider warp that is causing your difference.

Some solutions are: to use a temple (stretching the threads so that the edge threads don’t rub against the beater and apply friction), add speed to the beating process (flicking your wrist more than pulling against the cloth), and add weight to the beater (usually I like the first two better than this one).

––Madelyn

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