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screen printing => Waterbase and Discharge => Topic started by: endhymns on December 07, 2017, 01:46:54 PM
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So, we don't offer much in the way of pigmented discharge printing for client work for a variety of reasons, however, I recently had a new client request discharge for a small run and against my better judgment, I agreed on the contingency that testing went well. Fast forward, I ran a few tests which all washed well and moved forward with production. For peace of mind, I wash tested a few items from the production run and had mixed results, i.e. cracking. Some looked great, others not so much as seen be
My guess is that this is a direct result of bottlenecking on our small dryer, running to slowly on the manual and the ink getting a bit gummy in the screen and not being driven into the garment well enough.
Just looking for a quick opinion from more experienced discharge printers. About 1/3 of this small order does not look great in my opinion. Client has been made aware of the issue but the order has not left the shop. If this came off of your press, would you be reprinting? Should I chalk this up to bad judgment on my part, reprint and move on? Any input is appreciated.
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Yes we would be reprinting. As you stated driving it into the garment is critical to control cracking etc. 2% penetrant really helps with all that also. no more than 5% activator and managing your ink in the screen is very important you don't want gummy or it to start getting dry in any way. also again as you said dryer speed is a big part of the yellowing. Even with gas dryers some garments we need to speed up the belt to decrease the retention time to control the brightness. Last what white are you running and what mesh, squeegee etc?
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With most whites I add a bit of H20 as well. Flip the shirt inside out and chk penetration
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Thank you for the input. I am currently running CCI D-White with 5% penetrant and 4% activator. 150/48 mesh with a sharp 70 duro blade double stroked and driven in with zero off contact. Just double checked the insides of a few shirts and it does like the better prints are driven through further than the worst offenders.
The main reason that I have steered clear of discharge printing is due to a short tunneled infrared dryer. I'm typically walking a fine line between a full cure and scorching garments regardless of the ink system. My understanding has been that longer retention time on lower heat will ensure proper evaporation. Is the slight yellowing due to the print itself scorching? If I speed the belt up to reduce yellowing, am I then compromising cure?
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Most small infrared dryers lack air baffling systems which better enable the water evap/final cure so............quite possibly an issue. Further, manual printing does not ensure exact coverage/penetration which just adds to the complications
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Which takes me back to lapse in judgement...lesson learned. Thanks for confirming!
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I'd try a lower mesh count.
I don't offer discharge any longer but I used to and always had a better result with a 110 over a 156.
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With most whites I add a bit of H20 as well. Flip the shirt inside out and chk penetration
So how much is a 'bit' these days? 1%? 5%?
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Every shop is different (too many variables) so it will depend.
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So true and...........I've often seen slight inconsistencies in batch lots. Without viscometers and the like I just know when its right. Little bit like food prep.
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Thank you for the input. I am currently running CCI D-White with 5% penetrant and 4% activator. 150/48 mesh with a sharp 70 duro blade double stroked and driven in with zero off contact. Just double checked the insides of a few shirts and it does like the better prints are driven through further than the worst offenders.
The main reason that I have steered clear of discharge printing is due to a short tunneled infrared dryer. I'm typically walking a fine line between a full cure and scorching garments regardless of the ink system. My understanding has been that longer retention time on lower heat will ensure proper evaporation. Is the slight yellowing due to the print itself scorching? If I speed the belt up to reduce yellowing, am I then compromising cure?
5% is way too much penetrant in d- white and its gonna need the full 5% activator. Too much penetrant is for sure contributing to the discoloration.
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With CCI Dwhite I always ran it with 3% penetrant and 6% activator using a 135S (i forget the diameter, but I think also 48). I also print manually and I also have a "small" infrared dryer without working air. I run them through at 320 degrees max (laser temped about a foot from the exit of the tunnel, NOT your dryer temp which I wouldnt ever trust), 1:15 dwell which is the slowest my dryer will allow, but I run them through twice. Best results come from adding a floor fan blowing through the infeed of the dryer, and with baffles wide open. Its a ghetto setup vs a gas dryer with long dwell etc, but it works. The shirts will look fully discharged after the first run through, but they arent actually fully cured.
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Thanks Mimosa.
I'm running very similar using Ryonet Discharge white which I believe is a CCI product. I also have an infrared dryer with a little longer heat tunnel, but still run them through twice even with a crawl speed.
My question was when you said 'penetrant'. Is that just water or is there a special product? Called Ryonet and they were clueless on a product.
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Thanks Mimosa.
I'm running very similar using Ryonet Discharge white which I believe is a CCI product. I also have an infrared dryer with a little longer heat tunnel, but still run them through twice even with a crawl speed.
My question was when you said 'penetrant'. Is that just water or is there a special product? Called Ryonet and they were clueless on a product.
Penetrant is a chemical that allows for the ink to wick past the fibers of the garment. It also pushes past chemical coatings like silicon and starches. Allowing for better garment penetration and wash fastness of stubborn materials. If the ink cant get into and stick to the garment, it will look faded and washed out.
When you add it to the ink you will notice an immediate viscosity reduction. If you look really close, you will also see a change to the length/stringiness of the ink... Really hard to describe, but it visually cuts a bit shorter. Not that any of that really matters with a waterbase product ;) But you might notice it.
Hope this helps.
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FWIW the penetrant we use is made by Rutland, we get it from our vendor that carries them.
Pretty sure Matsui makes one as well but I could never figure out their naming convention.
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Thanks everyone, this is all awesome information. I'll run a couple more test prints with a lower mesh count, less penetrant (I am using the Rutland penetrant) and a touch more activator and see how results vary.
While we are on the topic of additives, I am also using 3% Matsui Fixer N and 3% Matsui Softner MG which I believe is the max load for both products. Do these sound like good starting percentages for now or would it be beneficial to back off?
I'll report back if testing goes well.
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Hard to tell from the pics, but the first one looks pretty good to me. I like to see ink taking the weave of the fabric like that,
for almost all ink systems/prints.
The question then becomes what changed between first and second. Ink? Printing? Dryer? Fabric?
With CCI white we typically use 5% activator, 3% penetrant and a dash of water depending on condition
of ink in bucket and environmental factors.
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Thanks everyone, this is all awesome information. I'll run a couple more test prints with a lower mesh count, less penetrant (I am using the Rutland penetrant) and a touch more activator and see how results vary.
While we are on the topic of additives, I am also using 3% Matsui Fixer N and 3% Matsui Softner MG which I believe is the max load for both products. Do these sound like good starting percentages for now or would it be beneficial to back off?
I'll report back if testing goes well.
I would skip the fixer and softener. the rutland penetrant and a dash of water as mentioned will be sufficient
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Never used the softener. The fixer is more meant for colors to prevent shade shift after washing (I thought). I have never added it to white.
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Never used the softener. The fixer is more meant for colors to prevent shade shift after washing (I thought). I have never added it to white.
20 years ago we would add softener when we would actually make base. With the bases available today and all the technology with colors, mesh etc I agree its just not needed. maybe TP will chime in as he is the resident expert on ink water base ink chemistry.
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I use to make WB/Discharge bases at Precision and elsewhere mainly for cut and sew programs and belt printing (cost around $3.00 per gallon!). You did not need to be a chemist but a bit of alchemy background helps. H20, concentrate, antifungicide, and anti foam usually did the trick. For DC the PH in the water had to be just so. No fixers/penetrants/lubes/LC additives/retarders were available. (We adjusted viscosity with urea and retarded with pharmacy bought glycerin) Today its usually a good idea to have a lube and penetrant on hand for when you need it. Printing WOW RFU DC flourescents a wee bit of both helps minimize/ eliminate build up on successive screens. Towel printing? Penetrant for sure. You get the idea.
BTW Rick a little bird told me you have a homogenizer tell K to get off his butt and fix it ;)
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I use to make WB/Discharge bases at Precision and elsewhere mainly for cut and sew programs and belt printing (cost around $3.00 per gallon!). You did not need to be a chemist but a bit of alchemy background helps. H20, concentrate, antifungicide, and anti foam usually did the trick. For DC the PH in the water had to be just so. No fixers/penetrants/lubes/LC additives/retarders were available. (We adjusted viscosity with urea and retarded with pharmacy bought glycerin) Today its usually a good idea to have a lube and penetrant on hand for when you need it. Printing WOW RFU DC flourescents a wee bit of both helps minimize/ eliminate build up on successive screens. Towel printing? Penetrant for sure. You get the idea.
BTW Rick a little bird told me you have a homogenizer tell K to get off his butt and fix it ;)
TP- That thing will never see the light of day again unless you drive down and want a picture of you and it.