Don't do it! Sharpies explicitly state 'not-for-fabric-marking' somewhere on the pens themselves or the packaging. Specifically, if you ever intend to wash your quilt, Sharpie ink can bleed, so it doesn't matter if the original mark is invisible.
The night before my youngest son's wedding I stayed up most of the night cutting out batik hearts on which wedding guests were asked to sign their names using an assortment of Sakura pigma micron (archival quality) and Sharpie permanent fine line pens I had on hand. I was going to incorporate these signed hearts into a border on my son's wedding quilt. While working on the pile of signed hearts to determine who signed and whose signatures were missing, I knocked over a glass of water and the pile was soaked. Sadly, the Sharpie-signed hearts bled rendering most of the pile of signed hearts unusable.
Last edited by frannella; 02-05-2023 at 02:17 PM.