TRADE: LED for 3140

[lancasterprinthouse]

Emulsion has a maximum sensitivity and needs to be in balance to other components.  We can make it resist water or solvents, and (harder)tweak it to make co solvent resistance. How you make your screens is crucial, in the end if you don't apply enough energy to the sensitizer during exposure you wind up with a partially cross linked stencil.  If there are un cross linked components, they are easily affected by water and will melt and breakdown. Quite often we fall into the trap of inspecting screens with our eyes and not a proven recipe, it looks good, has a great image, but breaks down with water base or discharge or HSA.  The recipe isn't about the image, it's about the quality of the exposure first and then the image next.  They are two very different areas of screen making.   So even with overexposure using an LED, you are applying a narrow wave length of the available UV Spectrum, whereas with MH you can get multi spectral bulbs that have more wavelengths at a much higher wattage at the source.  I can get good results with LED and post exposure with T9, but hit that same screen with an 8k Olite or a Tri Light 6k, a new bulb, proper exposure time (right up to over exposure)  and it can print long runs without hardeners and T9 will reclaim like butter.  Water base screens require an entirely different screen recipe than what you would use for plastisol.  Extra prep, longer dry times before exposure and before press set up, maximum high wattage multi spectral light, proper EOM, all help and it does require a bit more effort in screen making.  I can get great screens from LED, and the speed of image and exposure helps high volume shops, so you can make this work with LED, it just takes post exposure and the sun is the best if available.  Just realize there are stronger lamps that can make stronger screens, but either way can achieve success, the key is focus on getting maximum cross linked exposure.

I always appreciate your responses Al and our direct conversations are why I am here. Since speaking with you I have made a few changes to get better screens and they do well without any post hardening for 200 piece jobs or less but any long run jobs require a bit of extra work and as I had mentioned earlier in this thread, in rush scenarios that really puts us in a tough spot.

Lizard, DM your number.

[ABuffington]

Some ideas on speeding up a rush water base screen:
1. Always have a good inventory of screens that have dried for a day or more.  The storage area should be at 35% with a dehumidifier on.  This eliminates 30-40 minutes of coated emulsion dry time.
2. A hot box/room is an essential tool in making wb screens fast. The larger the heated area the faster the screen will dry.  Small areas get saturated with humidity, large areas can absorb more moisture without creating high humidity issues.  We need to drive all water out of the screen. 100 degrees with really good air movement.  I like fans up off the floor if I need to dry emulsion in there as well.  But right after development, squeegee off all excess water, blow out image with air, and put in a 100 degree hot box, or in front of a fan with a heater behind it.  20 minutes in the hot box, possibly longer with the fan.  We also used the top of our oven to bake the screen if it was raining.  Leave about 6 inches of the frame over the edge of the oven to promote air flow to avoid overheating, print side up, squeegee side down.
3. Put on LED print side up, squeegee side down.  Disable vacuum drawdown.  On a starlight just set Vacuum to zero, not sure on other LED's    Expose at 2x-3x original time.  Longer is ok, burn for as long as you can. 

[Admiral]

I think a lot of this can be solved with a better emulsion for water based.  We use good ol' SP-1400 for water based printing, have never had break down issues, even with a couple prints in the thousands.  We use the MS hardener after the stencil is dried.

We expose with the M&R Starlight, no glass.

[brandon]

Some ideas on speeding up a rush water base screen:
1. Always have a good inventory of screens that have dried for a day or more.  The storage area should be at 35% with a dehumidifier on.  This eliminates 30-40 minutes of coated emulsion dry time.
2. A hot box/room is an essential tool in making wb screens fast. The larger the heated area the faster the screen will dry.  Small areas get saturated with humidity, large areas can absorb more moisture without creating high humidity issues.  We need to drive all water out of the screen. 100 degrees with really good air movement.  I like fans up off the floor if I need to dry emulsion in there as well.  But right after development, squeegee off all excess water, blow out image with air, and put in a 100 degree hot box, or in front of a fan with a heater behind it.  20 minutes in the hot box, possibly longer with the fan.  We also used the top of our oven to bake the screen if it was raining.  Leave about 6 inches of the frame over the edge of the oven to promote air flow to avoid overheating, print side up, squeegee side down.
3. Put on LED print side up, squeegee side down.  Disable vacuum drawdown.  On a starlight just set Vacuum to zero, not sure on other LED's    Expose at 2x-3x original time.  Longer is ok, burn for as long as you can.

Just move to New Orleans. After exposing put screen outside for 3 min squeegee side facing sun. After 3 min the force of 10 gazillion gigawatts will have Marty and the Flux Capacitor back to the 1980's and all is alright.

But seriously the one non complaint of having the Sun for your neighbor is this.

[gotshirtz001]

I’ve got a 3140 and an Amerigraph 150 coming in Friday. Both units are 120V 20A.

$2150 for MSP3140
$1750 for Amerigraph

Located just North of San Francisco




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[gotshirtz001]

Still looking to trade? I just sold some equipment to a guy in Boise. Still needs an exposure... I have a 3140, he wants LED. We can 3-way.


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[Dottonedan]

Emulsion has a maximum sensitivity and needs to be in balance to other components.  We can make it resist water or solvents, and (harder)tweak it to make co solvent resistance. How you make your screens is crucial, in the end if you don't apply enough energy to the sensitizer during exposure you wind up with a partially cross linked stencil.  If there are un cross linked components, they are easily affected by water and will melt and breakdown. Quite often we fall into the trap of inspecting screens with our eyes and not a proven recipe, it looks good, has a great image, but breaks down with water base or discharge or HSA.  The recipe isn't about the image, it's about the quality of the exposure first and then the image next.  They are two very different areas of screen making.   So even with overexposure using an LED, you are applying a narrow wave length of the available UV Spectrum, whereas with MH you can get multi spectral bulbs that have more wavelengths at a much higher wattage at the source.  I can get good results with LED and post exposure with T9, but hit that same screen with an 8k Olite or a Tri Light 6k, a new bulb, proper exposure time (right up to over exposure)  and it can print long runs without hardeners and T9 will reclaim like butter.  Water base screens require an entirely different screen recipe than what you would use for plastisol.  Extra prep, longer dry times before exposure and before press set up, maximum high wattage multi spectral light, proper EOM, all help and it does require a bit more effort in screen making.  I can get great screens from LED, and the speed of image and exposure helps high volume shops, so you can make this work with LED, it just takes post exposure and the sun is the best if available.  Just realize there are stronger lamps that can make stronger screens, but either way can achieve success, the key is focus on getting maximum cross linked exposure.

Great post!  Well balanced with accurate information.