out gassing solvent prints

[MikeD]

Is there any way to gauge where a print is at in regard to out gassing all of the solvent in a print? Some kind of digital meter? 24+ hrs is recommended, but I imagine that a light yellow print would have less solvent to deal with than a print with lots of heavy dark inks.

Are there any tricks to expedite the process without risk aside from warm air circulation?

Thanks for the advice!

 

[Speedsterbeast]

I try a "scratch test" with my fingernail on the reg. marks to double check if I think I'm cheating it on the early side.

 

[MikeD]

Thanks for the tips!!
I definitely don't want to cut corners and create rejects, but time is money (even if it's not mine, but my boss'

I also have fans raised off the floor with a box / curtain on top. I can fit about 3 rolls in there; un-wound with gaps for the fan to pull fresh air through, pushing the solvent down and out. I just don't know what real affect that is giving because each print / design has different amounts of solvent ink in them.

I was thinking if I used an activated carbon filter and enclosed the unit, I could insert some type of air monitor probe thingy and observe the levels of solvent inside the unit.

Until then I will continue to wait the full 24hrs even with the assist described above.

Sorry about the redundancy! I looked for other threads, but I'm not the best at navigating this site or the interweb in general. I haven't even figured out how to post a pic up here, and I know there's instructional threads on that too!

I certainly appreciate the wealth of knowledge and experience all of the members share, as well as the patience with NOOBZ like myself!


Thanks

 

[a77]

I was thinking if I used an activated carbon filter and enclosed the unit, I could insert some type of air monitor probe thingy and observe the levels of solvent inside the unit.

If you figured something like this out.. that would be pretty cool!

A green light when safe to laminate

 

[MikeD]

If I can figure it out or find someone who already has I will surely share!

I forgot to mention using an IR dryer while the vinyl is headed to the take up helps as well.

Searching old posts here I found this insightful link:
http://www.youtube.com/watch?v=l-sV8qKeQrA&sns=em

 

[jfiscus]

We built a "suck box" with a fan at the bottom providing a downdraft for the rolls in it.
It works great, never had a roll that was printed the day before not be ready for lamination the next day since we've started using it.
You just have to remember to unwind/loosen the roll so the air has a chance to circulate over the print surface.

If a roll is wound up tight on a take-up reel it'll never outgas. Laying a print on a table is not very good either.
REMEMBER: solvents are heavier than air, so they're always trying to go downwards if they are escaping from a print.

 

[babykud]

Anyone have a picture of their "suck box"?

We built a "suck box" with a fan at the bottom providing a downdraft for the rolls in it.
It works great, never had a roll that was printed the day before not be ready for lamination the next day since we've started using it.
You just have to remember to unwind/loosen the roll so the air has a chance to circulate over the print surface.

If a roll is wound up tight on a take-up reel it'll never outgas. Laying a print on a table is not very good either.
REMEMBER: solvents are heavier than air, so they're always trying to go downwards if they are escaping from a print.

 

[Filmpro]

General remark about drying of solvent printed pressure sensitive vinyls:

• Most solvents rapidly migrate through the film into the adhesive, specially ecosolvent inks.
• For proper drying 2 things are important:
  1. air movement over the surface to enhance evaporation and reduce the solvent concentration in the most outer layer
  2. temperature to enhance migration from the adhesive to the surface

The migration is primarily driven by the difference in solvent concentration between top (print) and bottom (adhesive), temperature only speeds it up. So with little or no evaporation (rolled up, stacked) your solvent concentration will hardly change. Only boosting the temperature does hardly help you drying the solvents off while it has only limited influence on the evaporation, especially with ecosolvents.

The "suck box" is a perfect tool. I experimented with such a system a couple of years ago and it does dry the adhesive properly. Unfortunately I could not find a picture of it (yet). Will post if I find one.

A simple way to test how dry your print is, is printing a small test patch 1" x 6" in the darkest color of your print. Apply this after drying to clean glass and take an unprinted part of the same construction as reference. As long as solvents are in the adhesive you will feel the difference when removing the test strips.

 

[Lauren]

We built a "suck box" with a fan at the bottom providing a downdraft for the rolls in it.

Can you post a picture of this? I'm very curious to see it!

 

[MikeD]

picture

a "suck box" is just a box sitting on a fan that about 6" off the floor. The fan blows toward the floor, pulling the heavier than air solvent down and out. stand a roll vertically inside the box and unwind it so air can be pulled through all wraps.

 

[jfiscus]

Anyone have a picture of their "suck box"?

Here ya go!
Standard cheapo box fan at the bottom with a rolling vinyl rack used for the bottom to hold the rolls upright over that.
Otherwise it's just standard Home Depot stuff.

 

[babykud]

There is no top?

Here ya go!
Standard cheapo box fan at the bottom with a rolling vinyl rack used for the bottom to hold the rolls upright over that.
Otherwise it's just standard Home Depot stuff.

 

[Lauren]

That's cool! How many rolls of vinyl can you keep in there? How loosely do you unroll them?

 

[babykud]

I'm also wondering if it doesn't have a top if you did put a top on and mounted a fan to that if it would increase the dry time. How long do you usually leave a roll in for?

 

[MikeD]

with a typical box fan you can fit 3-4 loosely unwound rolls.
it's hard to say how long it really takes unless you monitor the level of VOCs coming out at the beginning and then periodically check and wait for it level off. each print can have different amounts of solvents based on design and profile ink limits

 

[MikeD]

there needs to be enough space between wraps to allow air flow

 

[Gino]

Well, there goes my vision out the window. I was picturing something entirely different.

With a name like Suck Box.... I had all kinds of things going through up there......................
​

 

[jfiscus]

There is no top?

Nope, it draws the air right down through the top. (fan is mounted to pull air downwards)

That's cool! How many rolls of vinyl can you keep in there? How loosely do you unroll them?

We've had "rolls" on every peg on there at times. As far as whole rolls, I think 6 is about the max, but you normally do not print 6 or full (or almost full) rolls in a day. Normally, you'll have 3-4 full rolls and a bunch of print-cut partial rolls in there.

I'm also wondering if it doesn't have a top if you did put a top on and mounted a fan to that if it would increase the dry time. How long do you usually leave a roll in for?

It wouldn't help much, it would probably move TO MUCH air actually. IF you had air pushed in there, it would flap the vinyl around more causing it to hit adjacent rolls and stick surface-to-surface. It moves plenty of air as-is.

If I had to build another (this one has been too full to add more rolls at times), I would just use a bigger fan to make it capable of more rolls. Always start with the largest rolls towards the middle. Even the outsides that are not directly above the actual fan dry almost as fast since the box is essentially a wind tunnel.