# New emulsion giving me trouble.



## brent (Nov 3, 2006)

Hi all,
After months of using the same gallon of emulsion I finally ran out. So I purchased a gallon of Kiwo poly-plus SWR at a local supplier. I'm not sure what brand/type I used before because it was given to me without a label. For the record, I use water-based inks.
Anyway, I knew I'd have to experiment with exposure times so I did. My set up for burning screens is very unprofessional. I shine a 150 watt bulb onto a screen roughly 19" below. With the old emulsion this always worked fine, taking 25 minutes to burn a screen. I tried 30 minutes on my first test burn with the new stuff, and the emulsion washed out well on some detail but on other parts it was slimy and spread around while washing out. So I tried it again with a 30 minute burn time and things were going ok, then I tried some warm water to wash it out and spots of emulsion outside of the design started coming off quickly. I tried again, burning another screen for 38 minutes and it wasn't slimy and detail started showing well but when i started rubbing it with my hand to clear it out the emulsion just started peeling off. I stayed calm during all this, no swearing or jumping up and down... I'm trying once more with a 45 minute burn, and I'll go look at the screen and maybe allow it to burn 10 or 15 minutes more. Kiwo's website wasn't that helpful to the method I use to burn. Googling made it seem like emulsions such as these change color when properly burned. Is that true?

If I can't figure out a proper time on my own tonite or tomorrow I'm going to order some exposure calculator films and try them out next week.

Does anyone have any tips or advice? Would this emulsion really change colors during burning? Right now it's sort of a dark green with a little blue hue when it's dried on the screen before burning, and a brighter blue in the bucket.

I'm also going to get a higher wattage bulb to see if I can reduce the burning time after I figure out what time is necessary with the 150 watt.

Thanks in advance. If my hair were long enough I'd be pulling it out.


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## ftembroidery (Nov 25, 2006)

Get an exposure calculator or exposure test strip from your emulsion manufacturer. Some of them are free, others (the really good ones) are not. They come with directions, but basically, you start with a screen that is ready to be exposed and put the calculator on it as if it were your positive for burning a screen. You expose it for TWICE as long as you think you should and then wash it out. From what you see on the screen as a stencil, you'll be able to calculate how long to expose your screens so as to achieve a proper exposure and stencil. 

Just so you know, I use a comparatively inexpensive exposure unit that has 4-24" florescent black-light tubes in it. It's a compression lid, not vacuum. I use Murakami TXR emulsion. I get proper exposures in 18-20 seconds, depending upon the thickness of the screen and emulsion (the coarser the screen, the thicker it is and the more emulsion it holds). Printers with Metal-Halide single-point vacuum top exposure units will be able to properly expose the same screen in aprox. 8-10 seconds. 

You're going to want to go to at least florescent black-lights for your source of UV light (unfiltered tubes). I don't recommend using a halogen light to expose even though you can get one with 500-1000 watts fairly inexpensively at your local hardware store, because halogen lights are a very poor source of UV light. In fact, halogen lights put off more heat than they do light, which is why they are used in higher-end flash dryers (mostly on automatic printers, but some can be used on manuals). Metal-Halide lights are the best source of UV light in the proper range to expose the emulsion, but the exposure units are more expensive.


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## brent (Nov 3, 2006)

Thanks for the info, Nick.
I should build a unit like you did. Can you tell me any more about it? Like it's overall dimensions, the size of the glass, or anything else useful before I design my own? Or if you could even provide plans for yours, that'd be super helpful. Thanks!


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## ftembroidery (Nov 25, 2006)

Brent,
I did not build my exposure unit. What I have is the "bottom of the line" exposure unit from Brown Manf (Harco). They sell it today for $575+shipping. If you go to Brown's site ... welcome ... and look at the picture of the FLC2024, you'll see what I have. Keep the picture handy and the specs as well. Then when you go to eBay or craigslist or someplace similar, you might find a good used or new exposure unit that is similar to mine. You can even find DVD/CD's on eBay containing instructions on building your own for probably around a $100 or so. Depending on your finances, you might even find something better.


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## brent (Nov 3, 2006)

Nick,
I just received some capital to spend on new equipment and supplies, but a good amount of it needs to be kept for buying blank apparel and recurring costs. I definitely need an exposure unit but to save money I'm going to build my own. 
A wooden box with four 24" black lights in it, internally painted with reflective paint, with a 20" by 24" sheet of glass is what I'm thinking of right now. Would that work fine for a basic system? 
I did further experimentation last nite with the new emulsion and my ghetto method of burning. I burned for around 63 minutes and the emulsion started washing out fine but as I sprayed some emulsion in the design started coming out. I have to get some screens made ASAP so I'm going to do a test burn today of 80 minutes and hopefully that will be enough but not too much. Having to burn a screen for 80 minutes is ridiculous, but looks like what I have to do right now...
Would a simple home-built black light exposure box like I mentioned above work ok? Is a lid of some sort necessary to have above the screens as they burn? Where could I get black lights like that?
Thanks for the help, I really appreciate it.


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## Solmu (Aug 15, 2005)

If you're looking at doing 80 minute burns (!!!), I'd consider trying the ol' "run out into the sun for a while" method of exposure.


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## brent (Nov 3, 2006)

Solmu said:


> If you're looking at doing 80 minute burns (!!!), I'd consider trying the ol' "run out into the sun for a while" method of exposure.


 I really really don't want to have to do 80 minute burns. I don't think the sun would do it any better, especially since it's cold winter time. I'm going to build an exposure unit ASAP.


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## ftembroidery (Nov 25, 2006)

Brent,

Yes, you can build an exposure unit similar to what I have. You have to buy UNFILTERED UV florescent tubes from your local Home Depot/Lowes, neighborhood ACE/TRUE VALUE, etc., hardware store. 

Yes, you must have a lid. It does not have to be hinged, but it is more convenient if it is. A piece of plywood with a piece of BLACK foam rubber (soft not like styrofoam) glued to the plywood (which should also be painted flat, non-reflective black). The black foam rubber should be just small enough to fit within the ink-side of the screen, and it should be about 2-2½" thick. Set it into your screen (the ink-side), with the positive taped to the shirt-side, and with the shirt-side against the glass, turn on the lights. To help ensure that light will not be "undercutting" your positive, weight down the lid to keep the positive and screen tightly against the glass. What I do, in addition to the black lid and black foam on my system, is I put a piece of black posterboard inside the ink-side of the screen that is only about ¼" smaller than the inside dimentions of the screen. The posterboard can be found at your local Longs/Rite Aid, etc. drug store in the school supplies isle. It's sold by Elmer's (the same people that make the glue) and it's made of a hard styrofoam-like plastic.


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## brent (Nov 3, 2006)

ftembroidery said:


> Brent,
> 
> Yes, you can build an exposure unit similar to what I have. You have to buy UNFILTERED UV florescent tubes from your local Home Depot/Lowes, neighborhood ACE/TRUE VALUE, etc., hardware store.
> 
> Yes, you must have a lid. It does not have to be hinged, but it is more convenient if it is. A piece of plywood with a piece of BLACK foam rubber (soft not like styrofoam) glued to the plywood (which should also be painted flat, non-reflective black). The black foam rubber should be just small enough to fit within the ink-side of the screen, and it should be about 2-2½" thick. Set it into your screen (the ink-side), with the positive taped to the shirt-side, and with the shirt-side against the glass, turn on the lights. To help ensure that light will not be "undercutting" your positive, weight down the lid to keep the positive and screen tightly against the glass. What I do, in addition to the black lid and black foam on my system, is I put a piece of black posterboard inside the ink-side of the screen that is only about ¼" smaller than the inside dimentions of the screen. The posterboard can be found at your local Longs/Rite Aid, etc. drug store in the school supplies isle. It's sold by Elmer's (the same people that make the glue) and it's made of a hard styrofoam-like plastic.


Appreciate the info. I'll start designing a system soon... Since I have several screen sizes I would need several custom lids with different foam rubber sizes, yes?
And also, what does the additional black posterboard do? Just curious.


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## ftembroidery (Nov 25, 2006)

Brent,

You would need to design a "light box" large enough to handle your largest screen. If you use a compression lid, yes, you'll need to develop a lid for each size of screen. If you build yourself a vacuum lid (there are plans on eBay all the time for about $20), you build a lid to fit your light box and smaller screens will work in it just fine. Remember, if you are going to build a light box with a vacuum lid, the box and lid will have to be large enough to allow the lid to completely and properly close and seal so the vacuum will form.

I use the black posterboard as a little added insurance against the light undercutting my positive. I'm sure you've seen foam rubber that has some spots or areas that are softer or stiffer than others, and to have even and equal pressure over the entire surface of the screen, I use the black posterboard to spread out the pressure evenly and equally. Maybe I don't need it, but it only cost a couple of bucks, so there's no loss in buying it and using it.


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## brent (Nov 3, 2006)

Nick, 
The poster board makes total sense, I just wanted to see what exactly you used it for. I get it now :]
I'm going to stick to compression lids for now. I have a roommate that has tools that I could use to make the unit and I'm sure he wouldn't mind helping me. I'll post pictures of it after I build it, hopefully next week. I need to build that and a light-tight cabinet for drying and storing screens (I already have designed plans for the cabinet).


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## FifthCourse (Feb 7, 2007)

when you guys wash of the emulsion after you burn it how hard is it to wash it off. I use the vastex exposure unit with chroma tech pl and i burn it for about 4 mins and it takes a good ten to fiften minutes to wash out use a regular house with Jet setting on the handle. I heard that you can use very low pressure and it will come out. I'm I doing something wrong? does the exposure need more time?


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## ftembroidery (Nov 25, 2006)

With respect to developing, or "washing out", the screen (obviously after exposure) I use a method that some others might be suprised at, but I'm sure I'm not the only one that does it this way.

First of all, I use the rounded or "dull" side of the scoop coater to apply the emulsion. I apply one coat on each side. This gives me a thick coating of emulsion which, when washed out gives me a stencil that has VERY defined edges for a sharp print.

I put the screen in my washout sink and use the pressure washer with the pressure washer TURNED OFF to lightly spray both sides of the screen. I then let the screen "rest" for 60-90 seconds. Then I TURN ON the pressure washer and wash away the emulsion (from the shirt side ONLY) to create the stencil. I start with the pressure washer about 18" away from the screen and work my way closer to the point of maybe 6-8". Constantly moving the wand quickly, I have not had a problem with "blowing away" the exposed emulsion from the screen . The unexposed emulsion (that covered up by the positive during the exposure process) washes away quickly and cleanly.

Once I'm satisfied with the washout, I then BLOT both sides of the screen, while keeping it in a horizontal position, to insure that any scum does not run down into the open portions of the stencil and clog the screen. Once blotted, I allow the screen to dry completely (usually in direct sunlight).


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## RichardGreaves (Nov 7, 2006)

brent said:


> I purchased a gallon of Kiwo poly-plus SWR at a local supplier.
> 
> I use water-based inks.


Poly-Plus SWR is not water resistant.

Better choices for water based inks from the KIWO brand would be:

KIWOCOL 225 WR dual-cure
Poly-Plus SRX dual-cure

or pre-sensitized new emulsions that are fast and water resistant
One Coat
Polycol Discharge


Who told you that you should use SWR for water based inks?

Go back to them and get them to sell you the right emulsion and ask them to help you calibrate your low power lamps. There is also Brown to help you with hot rodding the lamps of checking to see if your lamps are old and tired.


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## brent (Nov 3, 2006)

RichardGreaves said:


> Poly-Plus SWR is not water resistant.
> 
> Better choices for water based inks from the KIWO brand would be:
> 
> ...


so will there be problems using this emulsion with water? will the water break down the emulsion on the screen slowly?

The supplier I bought it from in town suggested it when I asked for an emulsion that worked with water based inks...

I don't think I could return it since I have already mixed it and used some.


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## RichardGreaves (Nov 7, 2006)

brent said:


> so will there be problems using this emulsion with water? will the water break down the emulsion on the screen slowly?
> 
> The supplier I bought it from in town suggested it when I asked for an emulsion that worked with water based inks...
> 
> I don't think I could return it since I have already mixed it and used some.


I predict the stencil will breakdown because it does not have the feature of water resistance. You may very well have good luck with your runs. You sensitized the whole gallon, so you have about 5 weeks to test until the diazo gets diluted and weak.

As I wrote, who suggested it? You now get to ask them what you should do since you bought what they suggested. If you can't consult with your distributor, you should shop for a new distributor.

You bought KIWO, so you get to talk to the actual manufacturer - toll free.
1-800-KIWO-USA and ask for Dave Dennings. You have a weak light source, so you want to get something water resistant AND fast exposing, which will be the SBQ emsulsions I suggested.

You should describe why you are using water-based inks and which inks.


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