Outgassing, please help!

[mwidmark]

We are having troubles with our translucent prints outgassing (drying).

We print with a Mutoh 1624 with ECO solvent ink.

From what I have heard, we lay down a lot of ink. We apply this vinyl to polycarbonate substrate. I have found the longer we let it sit before we apply it the more smoothly the application goes. (I am currently getting a lot of pushback about outgassing or drying time). I would like to let our backlits dry for 7 days before application. We have applied at about 5 days outgassing time and it works pretty well.

I guess what my question is how much drying time do you guys allow on your heavier inked materials?

If we have application issues and have to pull up the material there is pitting in our polycarbonate substrate. Is this caused from the ink not being outgassed completely?

ANY help is appreciated.

Thank you!

 

[Asuma01]

7 Days sounds extremely excessive to me.
There are curing boxes you can make easily that force air down through loosely rolled up print media.
Its basically a box with a box fan on top that blows downward. it helps with the curing time.

 

[mwidmark]

7 Days sounds extremely excessive to me.
There are curing boxes you can make easily that force air down through loosely rolled up print media.
Its basically a box with a box fan on top that blows downward. it helps with the curing time.

I agree that is seems extremely excessive. But we have tried shorter outgassing times and they do sit in a dryer similar to what you described. Basically we have a drying chamber with a box fan on steroids.

 

[mwidmark]

Has anyone else experienced the polycarbonate pitting? I have my assumptions that it is the ink because it shows up on the plex only where the ink is at. So, if we have a solid clear print with wording in the center the pitting will occur where the words are located.

 

[J Hill Designs]

what kind of application issues are you having?

and have you tried outgassing the polycarb overnight?

 

[petepaz]

wish the customers gave me 7 days for a job to outgas.....

yeah sounds like a lot to me also. we print with roland eco-sol printers and when i do back lit panels i print with a double pass and just let it dry over night and it's fine. when in a pinch i have let it out gas for 3-4 hours and it was ok but i like to go 24hr before laminating that material.

 

[bulldozer]

we usually do 24-48 hours. we have done many in less time than that and haven't had issues (that we know of). 5 days seems like a ton of time, let alone 7.

 

[player]

Could it be an issue with the polycarbonate?

 

[Mosh]

24 hours is usually a luxury at my shop....

 

[Joe Diaz]

24 hours is usually a luxury at my shop....

Same here although it is a necessity for certain jobs. Basically anytime we have to do an application where we are re-positioning or wrapping, we do the whole 24 hours thing, If it's a flat surface, we can usually apply after an hour or so. I'm betting it depends on the ink and printer though. We use a Eco-Sol inks, but it is usually dry to the touch after a few minutes out of the printer. 95% of the time we print on the high quality settings too. Either way, letting it dry seems to only effect the ability to re-position the graphic not the longevity. 5 days seems way too long though.

 

[bpatrick3]

Could it be an issue with the polycarbonate?

It could be an issue with the poly carb, I just recently found out the hard way that poly carb is one of the few plastics that will absorb moisture.

 

[mwidmark]

The polycarbonate is not the problem as we have been using this long before these issues started. The company I work for is not just a sign company which is why we can allow so much time for things to dry (but are fighting very much not to wait that long). We generally know what we need about a month out with the exceptions of a few surprises here and there.

I had asked my graphics department to step back our ink a bit because we have a company we subcontract some of our bigger backlits to and they can achieve our colors with less ink than we can. Instead of lowering the ink levels our engineers hired someone who actually upped them. So, I think our problem is that we are laying down too much ink. My theory is the pitting in the polycarbonate is from the solvents trying to outgass through the backside of the print because I do know that the ink will eat our polycarbonate. When we attempt to apply these backlits after 24 hours of sitting they are still really goey and stretch like crazy. The stretching causes even more issues with alignment.

In your guys' experience do you think that we are just laying down too much ink? I know we do double pass and we print on 3M IJ3650-114 for our transparent. We do not seem to have the same issues with our opaque prints which run on a different profile.

 

[jfiscus]

For backlits you have to lay down a bunch of ink to achieve the correct colors once it is lit.

If you would like to shorten your drying time (I think it cuts ours in half) try building a drying chamber like in this thread:
http://www.signs101.com/forums/showthread.php?112565-out-gassing-solvent-prints
An important fact to remember is that solvents are heavier than air, so they're always trying to go downwards.
So, if you put a fan in there put it in the bottom to suck them out.
Drying a print on a table is not a good idea, as the solvents are attacking the vinyl underneath them the whole time.

 

[mwidmark]

For backlits you have to lay down a bunch of ink to achieve the correct colors once it is lit.

If you would like to shorten your drying time (I think it cuts ours in half) try building a drying chamber like in this thread:
http://www.signs101.com/forums/showthread.php?112565-out-gassing-solvent-prints
An important fact to remember is that solvents are heavier than air, so they're always trying to go downwards.
So, if you put a fan in there put it in the bottom to suck them out.
Drying a print on a table is not a good idea, as the solvents are attacking the vinyl underneath them the whole time.

Interesting! I did not know that solvents outgas downward. I have attached a picture of what our drying chambers look like. We have two huge floor fans blowing up from the bottom. That may not be the best solution if they are outgassing downward, not upward. We are looking at getting a box fan replacment today, thank you!

 

[jfiscus]

Interesting! I did not know that solvents outgas downward. I have attached a picture of what our drying chambers look like. We have two huge floor fans blowing up from the bottom. That may not be the best solution if they are outgassing downward, not upward. We are looking at getting a box fan replacment today, thank you!

View attachment 100465

That is ours in the thread linked above. The box fan is on low speed as the solvents don't out-gas at a high rate of speed and it keeps the multiple rolls inside from fluttering around and touching each other.

 

[mwidmark]

That is ours in the thread linked above. The box fan is on low speed as the solvents don't out-gas at a high rate of speed and it keeps the multiple rolls inside from fluttering around and touching each other.

That is an awesome design! Way more high-tech than ours. I am going to talk to one of our engineering students to see if he can build something similar. Thank you so much for your help!