Hi, Lace here, there are some really wonderful folks helping make a doggie quilt for my mom. I have been asked what Pen they should use to sign the quilt patch? suggestions, thanks

a Pigma Pen is best...doesn't wash out, or fade....

I always use a Pigma pen, available at most quilting resources. The ink is permanent when heat set, and it doesn't smudge while you're writing.
Black is good for a siggy quilt, but the brown is also quite attractive.

Ditto for me!!! That's the only kind I would recommend.

I like ZigWriters better than Pigma Pens. They're cheaper too. You'll find them in the scrapbook department at Walmart. They're permanent, archival and don't bleed.

I use a pigma pen too. It just holds up better.

black pigma pen from Joann's, Walmart, Hobby Lobby or Michaels

So far the Pigma Pens.

I just purchased a 12 pack of fine point Sharpie permanent markers of assorted colors. I wanted to create fancy labels as well as use for drawing embroidery patterns. I am not sure about the acid issue, but hey write really write on fabric beautifully.

I have actually removed sharpie from several things. Permanent isn't always permanent. Sharpies are also not as crisp as a Pigma Pen. They tend to "bleed" out a little. I guess you should figure out how long the fabric is expected to last, how much laundering (sharpies really fade over time), what you are trying to make, etc. I figure that if I'm going to the trouble to make something special I want it to last as long as possible.