When I made a signature quilt, I used Tulip brand fabric markers in many different colors. The instructions said to wash the fabric first to remove the sizing. I used the butterfly style clips from the office supply store to clip each square down to a piece of plastic coated cardboard for the signing (used an old political sign). I sewed the quilt together after the signatures were gathered. Tulip fabric markers don't have to be heat set, but with pressing the seams it got heat set anyhow. Washed up fine with no running anywhere.
Here is a pic of what I did. Double irish chain with rooster prints in the middle. I had people sign in the blocks around the rooster. Sewed the block that far, got the signatures, then sewed the quilt top together. Some people wrote a lot, some just signed their name. I ended up with close to 300 signatures on a king sized quilt 120" x 120".
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