Problems with Chromablue

[AntonySharples]

We decided to try a different emulsion, away from Image Mate DZ343 to use Chromablue for our plastisol runs.  We did an exposure test, had our times dialed in for about the first 5-6 screens.  They came out perfect and my printer loved them.  Now, we cannot get a good screen.  It's like they are underexposed no matter what we do.  It has been raining for a couple weeks straight, so it is extremely humid.  I have to empty the dehumidifier in the screen room 2-3 times a day.  Some of these screens have been in there for a week and still seem wet.  Cannot use any pressure to wash them out, and none of the images are coming out clean and crisp.  Any suggestions as to what the problem may be?

[Doug B]

  I had the same problem when a gallon of my regular go-to went bad. Not only did I have problems
with washout, the screen broke down when I tried to use some solvent inks for some flatware. The
back of the screen also got sticky after just a few prints with plastisol. Finally gave it up. By the way,
we have a temperature and humidity controlled screen room so that was not the problem. I guess
Chromablue is just not for everybody.

[RichardGreaves]

An inexpensive hygrometer (relative humidity gauge), will measure the air condition in your drying area. Dryer is always better until about 10% Rh. Then stencils can get brittle.

[Orion]

DZ343 is compatible with plastisol. Chromablue is about $35 more a gallon and causing exposure issues for now. I know what I would do....

[screenprintguy]

Been using Chromablue for about 5 years now. Never have issues, so first, how long are you letting your screens dry for? Does the drying room/area have a dehumidifier? What type of exposure system are you using, florescent, quartz, Metal Halide, Led? Chroma blue should always expose perfect, if, your storage area is dry, the screens have been drying for at least a few hours, but over night is best, and you don't let them linger in the humidty too long before putting them in the exposure system. If you are using florescent, or quartz halogen to expose, you will run into this alot with almost any emulsion, been there done that, get away from it as fast as you can afford to. LED units are so inexpensive now compared to the MH units we used to drool over. Right now we use a 3,000 watt MH Trilight. Chromablue has a nicer wider latitude for exposing so depending on mesh types, counts, and coating usually 2 over 1 , the average LU for our unit is about 30 LU which translates to about 30 seconds. We us CTS so there is no film, no glass, so I'd say if I remember correctly, on a 1,000 watt workhorse MH unit with glass and film, that average was about 1 to 2 minute exposures. Humidity has a ton to do with it. If you are trying to expose screens that are still wet in the inner part of the coating that we can't feel, you will have a failure. Got to homedepot or lowes and pick up a digial hydrometer/thermostat in the garden department, shouldn't cost you more than 40 bucks. You should always have one and make sure that area is always below 50% humidity. It makes a huge difference. I have spent the past year trying different Pure Photopolymers, but for us we always go back to Chromablue. 54 bucks a gallon and never a pinhole issue, breakdown issue, and is very forgiving for fisheye if your screen guys slack off. Hope some of this helps.

Mike

[LuckyFlyinROUSH]

Sounds like its not exposed thoroughly. Are you using florescent tube lights?

Get a hygrometer for your room. Lowes has digital versions for 20 bucks. Our room stays around 30 no matter what we do with about 80 degree temp. If you have a screen in there overnight it should be dry.

Chromablue FOR A FACT goes on the screen much different than a lot of others we have noticed. Try round side 1/1 for high mesh, 2/1 for low mesh. We have noticed that this emulsion seems much less "watery" than other emulsions so no need for multiple strokes. Compared to Nazdars new Kiwo, and T&Js re branded emulsions.

Finally get yourself an exposure calculator from your ink supplier. They should hand you one free. Burn screens until you find correct exposure time. Our Workhorse 1000 halogen bulb was around 4 minutes sometimes....but now our starlight is 3.9 seconds. If its rinsing out that easy you know its underexposed. We can get right up on our stencil with our power washer and not blow it out.

Ask me if you have any other questions, we have not found a better emulsion that's so easy to use.

[AntonySharples]

Thanks for all the comments guys.  We have a 1k olec MH, so exposure unit is not the issue.  Our image mate is still exposing fine.  We run a dehumidifier, but with all the rain we have been getting, I think that humidity is an issue.  I spoke with Mick at Chromaline today.  I also think we might be coating too thick like someone else said.  We've made a couple adjustments and we are going to see if that works.

[jvanick]

Get yourself an exposure calculator, but better yet, a stouffer strip and tape it on the glass on your exposure unit.  Shoot it outside the image area on every screen for a while, and make sure you're always getting to a 'solid 7'. 

we have a google docs spreadsheet that I'd be more than happy to share a copy of to anybody interested that allows us to keep track of all the exposure variables  (for a while we were even keeping track of temperature and humidity in the screen room during exposure, but we have the room pretty dialed, so it didn't yield any good data). 

I think this link should work for anybody to be able to grab a copy:
https://docs.google.com/spreadsheets/d/1bsqE6POiBiCCztbQZlCZIOG_TlYNbZRtJ6_x7aTcShI/edit?usp=sharing

Stuff you can enter into the spredsheet:
screen/mesh/emusion/exposure time/screen thickness/emulsion thickness/coating style/stouffer strip result.
it calculates EOM, the number of steps to add to get to a solid 7, and what the new target exposure time should be.
when we're testing a new emulsion or mesh count, it's been invaluable for us to quickly and easily track our results.  (note my times are based on our starlight, so just use those as an example)

One other thing that really helped us:
if you're into buying tools, you may want to purchase a paint thickness tester on ebay.. $30-$100... it will help you dial in your emulsion thickness.  (if you get one, use the equation (emulsion thickness - mesh thickness)/emulsion thickness to determine the % of emulsion over mesh, if that number is over 25%, you're pretty much just wasting emulsion.  But the better reason is to see how consistent your thicknesses are.  5-10% difference screen to screen is enough to change your exposure times drastically.

[Screen Medics]

Save yourself some time and stress.  Call Chroma-Blue and discuss the issues with their technical service specialists.  They are going to know more about their product and its issues than everyone who has responded to you here...including me.
These companies spend millions of dollars so they know everything about their products and sincerely want to solve any problems with them that you experience.
Give them a call.  I always call the mfg. first and seldom need to go further to solve the problem I am experiencing.
Good luck to you.

[ScreenFoo]

I get the feeling they are not stressing, and are still using 343 till they figure it out.  (If so--smart thinking!)

I've never seen a 1K olec--is it an OEM model?
(The gear nerd in me made me post this