TSB
screen printing => General Screen Printing => Topic started by: StinkyDaddy on April 04, 2018, 01:13:31 PM
-
I've been flashing underbases for years, on this order I'm getting something like pinholes in the second color. They clear if I print the second color on a test shirt then run again. I recently moved my flash a little closer to the shirtboard and leveled it when I replaced the motor in my Flash A Matic. I'm wondering if that is the cause. It's about an inch an a half off the board. Using a 110v Odyssey flash. I've tried it with both quick white and bright tiger, flashing til a little white sticks to my finger after the flash. I changed out the navy ink too.
I'd appreciate any input.
Thanks,
Wm.
-
you are over flashing. try less time or temperature. should fix it.
pierre
-
Thanks Pierre.
I don't have temp control, but I just raised it about an inch higher.
Waiting for it to warm up and going to try it again.
If that's not enough I can raise it a little more, I'm at the min dwell time for the Flash AMatic.
-
Thanks Pierre.
I don't have temp control, but I just raised it about an inch higher.
Waiting for it to warm up and going to try it again.
If that's not enough I can raise it a little more, I'm at the min dwell time for the Flash AMatic.
A temp controller was one of the best things I bought for our manual press / flash. Kicking myself for not doing it sooner.
We sometimes set a fan up to cool the platens which can help with sticking.
Your ink should flash at around 220deg. Anything more is waste and can cause wash issues, plus these sticking issues. Get a friend to point a laser thermometer while you’re actually printing, or time yourself a bit to get an idea of how long the garment really gets flashed for. In my experience I ended up raising the flash a ton.
Good luck!
Sent from my iPhone using Tapatalk
-
You also have quite a few divots in your white. Have you tried a smoothing screen? Evening those out will also help with removing the speckles you see in your blue print.
What mesh count for your blue? Pressure? Squeegee? Angle? Hard or soft flood?
-
156 for the white, 230 for the navy, both about 20 newtons.
regular square end 60/90/60 for the white, 70/90/70 for the navy
push stroke manual
I'm guessing my angle is about 45.
Can't really say for pressures since I'm manual.
I just set up a unburned screen with some ink on it to try out smoothing.
-
I just set up a unburned screen with some ink on it to try out smoothing.
I have not had to resort to a smoothing screen, but wouldn't you want an 'exposed' screen just with no image to lock in the emulsion? Will ink break down unexposed emulsion?
-
Looks like you may need a little more off contact. Also consider dropping your navy screen 156. The roughness of your base will greatly efect how the rest of the printed colors look, the darker the top color the more it seems to be effected.
Also, are you printing base, flash, base, flash, navy? Or trying to glob the base on for anone pass white? If so, this is compounding the problem as well.
Sent from my XT1585 using Tapatalk
-
I just set up a unburned screen with some ink on it to try out smoothing.
I have not had to resort to a smoothing screen, but wouldn't you want an 'exposed' screen just with no image to lock in the emulsion? Will ink break down unexposed emulsion?
I didn't say that correctly, it was a screen with no image. I put it out in the sun for a few minutes to burn it.
-
Looks like you may need a little more off contact. Also consider dropping your navy screen 156. The roughness of your base will greatly efect how the rest of the printed colors look, the darker the top color the more it seems to be effected.
Also, are you printing base, flash, base, flash, navy? Or trying to glob the base on for anone pass white? If so, this is compounding the problem as well.
Sent from my XT1585 using Tapatalk
Base, flash, base, flash, navy. One flood and two print strokes.
Thanks for all the input.
I think the issue came from when I replaced the motor in my Flash A Matic, I leveled my flash and dropped it down really low to the shirtboard, about an inch and a half off. I think the reason it's been tough to figure out is that having the flash so close and times so short it's showing the differences in temp across the area of the flash. I noticed while I was testing yesterday that some areas were still wet and other spots were dry. I'm going to raise the flash again and increase the time a little more. Hopefully that will give me a more even flash over the whole image.
-
I just set up a unburned screen with some ink on it to try out smoothing.
I have not had to resort to a smoothing screen, but wouldn't you want an 'exposed' screen just with no image to lock in the emulsion? Will ink break down unexposed emulsion?
I didn't say that correctly, it was a screen with no image. I put it out in the sun for a few minutes to burn it.
Thanks for the follow up.
-
a one minute dwell time for a flash? Unless I missed something, that's an extremely long time to flash, hence the remarks about over flashing. It should only be a few seconds, at least that's my experience. I don't spend much time on press, but on a rare occasion I do, manually, and I count to 5, and it's flashed, an old Hopkins flash. On our auto, it's a few seconds.
Steve
-
a one minute dwell time for a flash? Unless I missed something, that's an extremely long time to flash, hence the remarks about over flashing. It should only be a few seconds, at least that's my experience. I don't spend much time on press, but on a rare occasion I do, manually, and I count to 5, and it's flashed, an old Hopkins flash. On our auto, it's a few seconds.
Steve
The "minimum" dwell. It was about 5 seconds, if I turn the dial lower than that the controller jumps down to one sec.