marking pen
 

Recently at the $shop I bought a couple of neon gel pens (orange & hot pink). They worked great just now when I needed to make two HST's for a sample block.

Did the marks wash out?

They may work great but can you remove the ink permanently. That's the problem with the Fixion (sorry if its spelled wrong, early in the morning, not thinking yet) is that they work great but not always easy to get out, PERMANENTLY. If you contact the company they will even tell you they weren't made for fabric or any service where you need to make sure it is removed for the long hall. If its just the center line going thru the HST where you cut, then no problem because it'll be in the seam line

My only comment about Frixion is this, if it shows up again when you put it in a freezing cold car overnight, or in the freezer for some stupid reason, then pop it in the dryer for a few, and they will go bye-bye again. I am not worried about 30 yrs. down the road, what will happen to that underlying fabric. They are so helpful and great for marking that I prize every one of them.

Are you using them to draw the cutting line (sewing guideline) for your HST? Not a line that needs to be washed out, correct?

I am only using them for a cutting line. I wouldn't trust they would wash out.