Is "over flashing" actually a thing?

[spencer_L&KC]

Like the title says, is over flashing actually something to be cautious of? Or is it a myth? Obviously leaving the shirt under the flash for extended times isnt great, but when it comes to making sure to keep a print tacky, how important is it really?

Has anyone here ever seen top colors not adhere to a base, and maybe even come off, not from under curing, but from flashing too long?

Has anyone here ever seen a second pass of white come off the first pass?

I have been printing since 2011, printing professionally since 2018. I have never once seen a top color or second pass of white detach from a base, and I know for sure that at some point I "over flashed" a print or two in that time. Still though, no issues with top coats adhering to the base. Another user on here mentioned in another thread that "over flashing" could be a myth, so I am very curious to hear what some of the other pros think on the subject. I am not a newbie, but posted here so actual newbies can find and learn from this thread. 

So what say you? Thanks for reading!

[prozyan]

As far as ink failure on top colors, you'll ruin the shirt long before you see any issues there.

The only time over-flashing is an issue can be on some high polyester items, as excess heat exacerbates dye migration.  But that is easily solved with any decent ink.

[mk162]

Yes, it's absolutely a thing.  Over flashing can lead to what look like white dots in your print. they only show up after the oven, or even when you pull your shirts.

[tonypep]

Or when you melt an $85.00 blank. It happens. Total margin killer.

[spencer_L&KC]

Yes, it's absolutely a thing.  Over flashing can lead to what look like white dots in your print. they only show up after the oven, or even when you pull your shirts.

I always assumed that was fibrillation. How does over flashing create those bumps in the underbase? The conveyor gets hotter than the flash, so wouldn't simply running them through the dryer create those bumps if heat is the cause?

[Maxie]

You will definately get white dots if you over cure, especially when you print solid colors over a white base.
I also assume that the top colors won't adhere to the base as well if it is overcured.

[spencer_L&KC]

You will definately get white dots if you over cure, especially when you print solid colors over a white base.
I also assume that the top colors won't adhere to the base as well if it is overcured.

Do you mean "over flash" and not "over cure"? The flash should not be hot enough to cure ink.

[mk162]

You will definately get white dots if you over cure, especially when you print solid colors over a white base.
I also assume that the top colors won't adhere to the base as well if it is overcured.

Do you mean "over flash" and not "over cure"? The flash should not be hot enough to cure ink.

correct, overflashing can also cause ink adhesion problems between your base and top colors.

[Admiral]

You will definately get white dots if you over cure, especially when you print solid colors over a white base.
I also assume that the top colors won't adhere to the base as well if it is overcured.

Do you mean "over flash" and not "over cure"? The flash should not be hot enough to cure ink.

correct, overflashing can also cause ink adhesion problems between your base and top colors.

It can also cause registration issues by garments shrinking / tack being rendered much less useful due to excess heat on the platen.

[spencer_L&KC]

You will definately get white dots if you over cure, especially when you print solid colors over a white base.
I also assume that the top colors won't adhere to the base as well if it is overcured.

Do you mean "over flash" and not "over cure"? The flash should not be hot enough to cure ink.

correct, overflashing can also cause ink adhesion problems between your base and top colors.

So thats what ive been told, but I have never experienced adhesion issues with bases and top colors. That is why I started this thread, after another user mentioned they believe that over flashing is a myth. I am sure I have "over flashed" a print or two over the years. I feel like the flash should not be hot enough to cure ink, so how can it cause adhesion issues? Wouldn't both layers get hot enough to adhere in the conveyor?

And I am super curious if anyone can explain how flashing can cause those little white bumps through colors. How is that even possible if the conveyor dryer temp is far hotter than the flash, and it doesn't cause bumps. So how is it possible that flashing is causing those bumps?

I want to get to the bottom of these issues. Can anyone explain how these phenomenons are happening?

[AntonySharples]

Yes, you can over flash…quite easily too. You most certainly can cure ink under a flash….a lot of people start like that. If your base is cured first it causes adhesion issues for top colors. Don’t believe it? I had a customer send me a pic of a print they did last week. Top colors literally peeling off.
The white “bumps” are from blistering. Underbase gets too hot, it blisters and pops and pits. That’s what you are seeing.