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Your best bet is to buy one and test it yourself, that is what I did. I posted under Quilt in the freezer. I love them for drawing Red Work embroidery patterns because I stitch over the line and then erase any bits showing with the iron. I also like them for small sewing items. They definitely have a place in my sewing room. Would I use then to mark quilting lines on a quilt going to a show? Probably not but I have seen on major quilt blogs where others do. Frixion pens are like asking if you pre-wash fabric or not, it is a personal choice.
I love the & use them on a lot of my quilts.
A question- I have found the 3 pack of red, blue & black at Staples. Is there a silver or white available for marking on dark fabrics?
But, to each her own. If you want to use them in your quilt, by all means do so. As I said, I still prefer to use products that I KNOW are safe.
They have less chemicals in the ink then in the fabric printing process. I use them, even for writing on paper.
I love mine, I did notice a line on the fabric when I had used a black one, but I had left the project several weeks, thought that was why and I haven't washed the project yet, I usually use the red one but am pressing as I go and haven't had any problems.
I just discovered these last week! My friend told me about them, and then we found some at a quilting/sewing garage sale. I used it on a darker batik and did notice a thin line that looked like bleach. It's small and not noticeable unless you know what you are looking for.
I was told by a company rep that they react differently on Batiks versus quilting cottons. BUT - can't remember what the difference is!!! I think the comments about white lines was the reaction on Batiks.
We are here to learn how to live in heaven - I'm still learning.
While I am aware of the problems with using Frixion pens, I confess that I use them often, usually on light fabric. So far, I have been pleased. I purchase mine from Staples. I do test them on a scrap of fabric before using them and do not use the on fabric that has a bleach line when heated.