Works great, even on geissele ddc - Birchwood Casey Aluminum Black Felt Tip Touch-Up Pen

I had an ugly scratch on a Geissele DDC hand guard after slipping with a file. This pen worked great for masking that defect.

It’s a clear acidic liquid in the pen. So long as the work piece is clean, you will see the color of the bare metal change as you apply.

For DDC I applied and wiped over multiple passes. 3 to 4 passes was enough for me to mask the defect I had.

It worked great at masking some wrench marks in a muzzle brake after a pin and weld too.

Not sure what the bad review is about but if I had to guess it’s possible theirs was dried up. Maybe bad luck, but mine worked well.

I handed the firearm to a friend and asked them to find a scratch. They didn’t know where to look and couldn’t see it.

If you know where to look you’ll find it, unless you feather the edges and try to blend.

I will be trying that next on an old Colt lower I have. We will see.

The liquid in the pen does not change the color of already anodized metal. Only the bare metal.

I would 100% wear gloves while using this. It’s quite acidic.

For the price I am very pleased with the results.