Frixion Pens, sewers friend or foe

I've heard some amazing things about these wonderful Frixion (pronounced friction) pens.

There is a rubber tip which removes the pen markings, but apparently, so does heat.

As a sewer , you can mark out your work comfortably knowing that once pressed on with a moderate temperature iron, the pen marks disappear... 

...but not for good it seems.

It seems that the marks reappear when the fabric is exposed to a very cold environment.

So, I've found some scrap cotton fabric to test this on before going full force on my actual sewing, the last thing I need is a customer complaining that there is pen all over the work.

Here's my little sketch.

I have drawn very lightly on some parts, and very heavily in other parts.

I'll hide half the image with a metal ruler and press on 2 dots heat.

With barely any pressure, the pen markings disappear. 

Now to hide it in my freezer for 15 minutes, just enough time to cook the cinnamon rolls I've just found in there.

I'll come back after 2 minutes, 5 minutes, 10 and finally 15 minutes, then I'll allow the fabric come back to room temperature.  It's a warm day here, about 16C, so let's see what happens.

Here are the results.

After 2 minutes: no change

After 5 minutes: some return of colour

After 10 minutes: the text that's lightly drawn has reappeared  

At 15 minutes: no change since the 10 minute check.

Ok. So now I'll press on the image with a hotter temperature.  Let's go all the way to 3 dots on the iron; for linen. 

I'm going to prolong the press and let's see hat happens this time Ive popped the fabric into the freezer. 

While it's freezing in there for 10 minutes, and I enjoy my cinnamon roll, I wonder if I should have brushed the fabric to remove the pen 's ink particles ?

If no luck, we will try that next... 

Ok. So cinnamon roll eaten, 10 minutes have gone and we are back to the reappearing marks. 

Never mind. But what we do know at this point, the heat doesn't have to be great, but the freezing doesn't bring all of the colour back...

This time we will try a fridge. Let's be honest in the UK we hardly live in temperatures of -18C 

The fridge is set at 4C. New image, and as before, 2 dots on the iron the press away half the image. But this time I've used a lint remover rolled over the ironed side to pick up any ink particles it can, although I suspect they disappear into the fabric. 

After 5 minutes in the fridge.  

And after 20 minutes no change. You can however, see a tinge of red. But I did go to town on that colour. 

So the resounding result, it works but be aware in an extremely cold environment the colour will come back.

So. I think I will use them, but lightly xx 

Update...

I was asked to experiment with washing the fabric after using the pens. 

So with a new clean sponge and a dab of water, the ink disappears when I rub the area. 

Then I've put the fabric back in the freezer for 30 or so minutes. 

This is the result : 

The far left (the washed area) is completely free of the markings and the other images return, albeit lightly.  So it seems, a dab of clean water will wash away the ink particles, and the criss cross pattern to see if colours seep into each other wasn't a problem either. All in all, it seems, give the marks a little dab of water and a press, and you've hopefully got back to a non marked fabric...

Please do comment below with suggestions and ideas for further discussion and investigation.

Have fun x