[theory] What makes white ink so hard to print? Part 2

[blue moon]

As the ink warms up, the body becomes thinner allowing you to print on top of the fabric as you need less pressure to clear the mesh

so the thinner the better? Is there such a thing as too thin?

pierre

[ebscreen]

The downsides of a too thin ink would be opacity and fiber matte down.

Easy to print though.

[blue moon]

The downsides of a too thin ink would be opacity and fiber matte down.

Easy to print though.

What about the perceived stability? The curve at the bottom is a lot flatter then it is on the side. A slight change in temp at 140 would also cause quite a bit of difference in the viscosity! So thin and stable is good, right?

who here is preheating their inks???

pierre

[jsheridan]

so the ink is at 72 when you pick up the bucket, right? and how long does it stay at 72?

pierre

In 27 years.. i have never put a thermometer in a bucket of ink and I have no desire to do so.

what I know.. cold and hot ink print like s.h.i.t.. warm ink prints like the beez kneez.

[tonypep]

Not me! In all honesty, with all the great white plastisols out there and with proper press and pre-press paramenters this process is not hard at al. Its pretty easy. We just don't do it often because its rarely necessary at this point.

[Colin]

I love what you are attempting to accomplish Pierre!

Everyone needs to remember though...... ink prices are vastly different...... ink quality is vastly different....  Typically reflected in pricing.

For everyone who wants to chime in about the right ink, right speed, right production heat parameters.... Please remember what "quality" of white ink you are working with.  Also whether the ink is made for cotton/low bleed (cheap)/low bleed (expensive).

Proper production parameters for cheap cotton ink, will not be the same for expensive low bleed ink....

Please post the name/type of ink you are talking about and what your typical production atmosphere is, run size, fabric type, etc...

Case in point:  The Comet White from Ryonet.  I thought the viscosity was way to low for what we do.  It would not matte fibers well.  But I was testing on 100% 6.1 oz cotton.  Those who loved it did their testing on tri blends and ring spun cotton.  Different fabric gave different results with the same ink.

Also, what mesh/mesh opening are you testing/printing your whites through?  Screen tension?  Off contact?  Squeegee blade type/sharpness?  Hard fill or soft touch with the flood bar?

Let's make sure we talk about allll our parameters when we pitch in.

This is my 2 cents coming from an ink manufacturing background and a production background.

Keep the convo going!

[blue moon]

I love what you are attempting to accomplish Pierre!

Everyone needs to remember though...... ink prices are vastly different...... ink quality is vastly different....  Typically reflected in pricing.

For everyone who wants to chime in about the right ink, right speed, right production heat parameters.... Please remember what "quality" of white ink you are working with.  Also whether the ink is made for cotton/low bleed (cheap)/low bleed (expensive).

Proper production parameters for cheap cotton ink, will not be the same for expensive low bleed ink....

Please post the name/type of ink you are talking about and what your typical production atmosphere is, run size, fabric type, etc...

Case in point:  The Comet White from Ryonet.  I thought the viscosity was way to low for what we do.  It would not matte fibers well.  But I was testing on 100% 6.1 oz cotton.  Those who loved it did their testing on tri blends and ring spun cotton.  Different fabric gave different results with the same ink.

Also, what mesh/mesh opening are you testing/printing your whites through?  Screen tension?  Off contact?  Squeegee blade type/sharpness?  Hard fill or soft touch with the flood bar?

Let's make sure we talk about allll our parameters when we pitch in.

This is my 2 cents coming from an ink manufacturing background and a production background.

Keep the convo going!

great points!

so we can control the viscosity of the ink by controlling the temperature. Could we use the same ink at different temps to adjust for the substrate requirements? Why? Or, Why not?

The ink temp is directly related to the platen temperatures. Other than the guys with a IIID, anybody else measure the platen temps? Regularly?

pierre

[jsheridan]

so we can control the viscosity of the ink by controlling the temperature. Could we use the same ink at different temps to adjust for the substrate requirements? Why? Or, Why not?

The ink temp is directly related to the platen temperatures. Other than the guys with a IIID, anybody else measure the platen temps? Regularly?

pierre

We have the new flashes from MSI that have the eye that reads the surface temp of the shirts/platens so yes I can control my heat.

We also have honeycomb platens, that cool off very quickly and do not hold heat like the blue boards do. In fact the blue boards are known to get so hot you can't even touch them which in turn heats the inks in the screen well into the 100+ range and even so hot that inks in the screen get tacky and start to gel.

[blue moon]

so we can control the viscosity of the ink by controlling the temperature. Could we use the same ink at different temps to adjust for the substrate requirements? Why? Or, Why not?

The ink temp is directly related to the platen temperatures. Other than the guys with a IIID, anybody else measure the platen temps? Regularly?

pierre

We have the new flashes from MSI that have the eye that reads the surface temp of the shirts/platens so yes I can control my heat.

We also have honeycomb platens, that cool off very quickly and do not hold heat like the blue boards do. In fact the blue boards are known to get so hot you can't even touch them which in turn heats the inks in the screen well into the 90-100+ range.

our platens (also honeycomb) are running at 120 degrees at the offloading station which drives the ink in the first and last head to about 100 degrees. I think that's actually a pretty good place to be based on what we've seen so far. . .

pierre

[ABuffington]

We set the heating pad to halfway, never took a temp on it. Grainger sells metal heaters that can wrap around the 5 gallon pail. We had one and placed near the top of the 5
Gallon pail worked better thanjust heating the bottom of a full 5 gallon pail.  It was impossible with the heating pad to ever fuse the ink, they just don't get that warm.  On really cold days we stored it in the screen room which was temp controlled to 80 overnight. Of all the methods though the band with the 5 placed in a turnabout turned on for 10 minutes at a slow speed worked the best to get consistent viscosity and match print and pressure speeds from the day before.

[alan802]

For what it's worth, we printed a 500 piece run today and 2 locations so the white ink had 1000 strokes on it at the end and it reached 121 degrees.  I was printing at 30"/sec with a Dr J blade.  Opacity didn't really suffer that was noticeable by eye.  Viscosity changes were obvious but I did compare the first and last print.  It got up to 98 in the shop today while doing the print run.  We have another 750 piece job to run on monday so I'll observe temps on that run as well.  I may slow down to 15"/sec as long as it doesn't affect opacity and other variables or quality and see what type of ending temps I get.  I don't know if anyone can do anything with these numbers but I'm observing just because I want to and this is a nerdy subject that I get into.  Pallet temps got up to 150 on the backs but stayed at 135 on the front run.  Had a slightly longer flash for the larger back print.  That's all I got.