I would stick to coating with the sharp side of the coater because you have a relatively weak light source. If you're having a hard time washing out even with a pressure washer, you may be over exposing. It's winter, so there's not a lot of humidity in the air-I presume- but if there is a lot of moisture where you're prepping your screens- it'll cause a problem.
More trial and error?

 

i appreciate your reply to my post. just to clarify i am not having a hard time wshing it out with a presuure washer i am having a problem keeping it "from" washing out. the longest i exposed a screen with a step test was somewhere around 30-35 minutes it shouldnt take that long even with a thin coat once on each side with the sharp edge of my coater i dont think. i never had problems in the past with exposure time and emulsion with a 500 watt halogen although i did make a box for it that was lined with tin foil with the light resting on top of it shining from above at about the same distance i have now which is 18 inches. i dont think an enclosure is the problems beings that i have seen videos where people have exposed screens for less than ten minutes with the exact set up i am using now.

 

Find a happy medium...


If it washes out - Burn it longer.

 

When I had the exposure set up you are speaking of my light source was 12 inches away from the screen. I used a QX3 emulsion and it took approximately 8 minutes to expose the screens. I only coated once on each side using the sharp edge of the scoop coater. From reading your post the only two differences in my set up and yours is the distance from the screen and the emulsion. The distance should not cause the problem you are describing. It will just take longer to expose. 500w halogen units that are sold at Screenprinting supply stores as a kit are 21 inches from the screen and it takes about 18-23 minutes to expose a screen. My guess would be that you got a bad batch or old emulsion. I had a similar problem where I bought emulsion and the same day all of my screens washed out. I ran to a print shop near me that helps me sometimes to get his opinion on it and when he tried the same thing, the emulsion washed out. This shop has been in business for 47 years so I trust his opinion and he determined that the problem was the emulsion. He gave me the number to a local supplier he uses and I never had the problem again.

So my "guess" would be bad / old emulsion.

Katrina

 

i appreciate all your replies. i could still use more.so basically yes if it washes out burn longer . so i guess my fear is what will ahppen if i over epose it like by alot. i was think since it could expose for 30 minutes i would start the step test at 30 minutes and move an inch every 3 minutes. so tell me this if emulsion is properly exposed it will not i repeat will not spray out even with a pressure washer????? cuz if thats the case i will over expose that f-ing emulsion till it begs for mercy and hit it with my pressure washer and spray that son of a b-word as much as i want and it wont spray out. right????

 

Start by reading the FAQ I have on the Ulano web site about hardness being the first responsibility of the screen maker. The stencil has to survive the development process before you can expect to use it for printing.

Measure your exposure with a Stouffer 21 Step Transmission Guide photo positive. 5.5 inches. Expose so a solid step 7 SURVIVES washout. You can then fiddle with your exposure amounts and get visible feedback like learning to shoot a machine gun. Ready Fire Aim! The 21 step doesn't care what lamp you use, it only cares when you reach a volume amount of UV energy. Low energy lamps just take longer.

How long does it take to fill a gallon bucket with water? With a medicine dropper - 2 hours. With a fire hose - 2 seconds. It's still 1 gallon! Time is relative.

http://www.ulano.com/FAQ/FAQexposure.htm#Q1
Repeatability, actual numbers with a dependable control guide - The Stouffer 21 Step Transmission Guide. US$10. Don't expose without it.
Printer Information and Training for Screen Printers

Water resistant stencils require completely cured/hardened exposure be cause the ink itself has the solvent that can break down the stencil - water.

Overexposure
The sensitizer in emulsions cross link and change the stencil into something that will not dissolve in water and rinse down the drain. After a certain amount of UV energy exposure, the stencil has no more sensitizer to cross link, so what's the point of exposing any longer?

Shops with inferior positives that don't stop UV energy should worry because they will allow a mild 'crust' to form on the surface of the stencil where the positive failed.

Search these forums for "21 step" or "Stouffer" and especially "dime". If you put a dime or aluminum foil on the stencil, you can expose for hours and you will just be spending your time watching nothing happen.

Under Cutting
Please don't confuse under cutting of wide or multiple light sources as over exposure.
Exposure FAQ Screen Making Products how to measure exposure

When UV energy lands on a positive at an angle it will CHOKE small lines and dots. You can't stop it except to compensate by anticipating and making fine lines fatter. You can fool yourself by under exposing the stencil but at the cost of durability and making the stencil harder to reclaim. Yes. Harder to reclaim.


I will read all these long posts after dinner and reply later.

 

Dretu Aliur,

What private label emulsion did you buy first from the supplier.

What emulsion did you just buy and sensitize?

Who is your distributor?

 

I just thought of something else. This may have been mentioned in your post but it was so long I just couldn't bare to read it again. But I just thought about the vellum you may be using. Sometimes when the vellum isn't dark enough it will allow light to pass through causing all the emulsion to wash out.
Something to check. If you did mention this then sorry for the post otherwise make sure the image is very dark.

Katrina

 

I just thought of something else. This may have been mentioned in your post but it was so long I just couldn't bare to read it again. But I just thought about the vellum you may be using. Sometimes when the vellum isn't dark enough it will allow light to pass through causing all the emulsion to wash out.
Something to check. If you did mention this then sorry for the post otherwise make sure the image is very dark.

Katrina

What does Vellum look like? Is it a transparency film as well? Im a little confused on this, i heard the name before, but don't know what it is...

p.s Im a newbie at Screenprinting so have patience on me. lol

 

I was wondering if there are some emulsions that just will not allow the UV rays from a 500 watt halogen worklight (with uv filtered glass face taken out of course) to penetrate it enough to allow a proper exposure???

the reason i ask is i have this emulsion i have yet to figure out.

As much as I like work quartz halogen lamps with their APPROXIMATELY 27% IR energy, 3% UV energy and 70% visible energy - How do you know there is any UV energy in your bulb? It may be one of the many UV resistant coated bulbs.

i was obviously paired up with an emulsion that didnt match my experience nor my equipment.(the supplier i bought it from pushed it on me even though he knew i was using a 500 watt halogen.... geez i wonder why??

could it be cuz it was their companies brand emulsion...hhhmmmm i wonder.lol.) thats beside the point

Which emulsion? What distributor? Is it a slow emulsion or a fast emulsion. If you added diazo, that is always a slower exposing emulsion.

i am stuck with this emulsion and i already sensitived it so returning it is out of the question. so i tried how thick i coat my screen at first i used the rounded edge and coated t-shirt side twice than did the sqeedgee side once,and dried it with a fan on a medium setting for like 2 hours.,and exposed it with a step test but no step was fully cured it washed out most with a shower sprayer the rest with a pressure washer.

How long were the steps?

Dry is very important to me, but not at the top of the list. If the surface is dry, UV energy will harden it and it and you will see it in development.

i tried again this time only coating my screen with the sharp edge once on the t-shirt side and once on the sqeedgee side. let that sit in front of a fan for 4 hours this time and exposed it with a step test ,the first step starting at 10 minutes,and 3 minutes every inch after that. it all washed out with the pressure washer. i only needed stencil remover for the haze of emulsion left over.

So you know with that mystery diazo emulsion, 20? minutes isn't enough exposure. Do you trust the emulsion, or the lamp? You need to find out if the emulsion works. If it is sunny outside, you can use the sun make a pass/fail test and see if it can harden your mystery emulsion.

so maybe you guys can help me figure this one out first off "yes" it is winter here and "no" i dont have a dehumidifier. so i figured if i let it sit in front of a fan for 4 hours that would be plenty of time. i even went so far as to hit the screen with a hair dryer for a few minutes on both sides of the supposdly dry emulsion juist to eliminate the "surface" humidity that may have been present.

i dont degrease my screens but they r brand new so i know it doesnt have toooo much grease (plus i am pretty sure my stencil remover has a degreaser in it anyways)on there but i read something the t-shirt guru "richard greaves" said once that degresing isnt that neccessary with direct emulsion.

but honestly i dont think degreasing is the problem cuz years back when i used to silk screen shirts for profit i never degreased my screeens and i used the over and over again......so the emulsion was not pre sensitized but i mixed it up with the sensitizer till my arm was about to fall off so i dont know if that wopulbe be an issue at all, if by chance i didnt mix it up enough even though i am a man who has had many experince in such matters being into construction, painting , and other such activities. so am i not drying them long enough??

Degreasing will not effect exposure, but it will effect the surface tension of liquids like emulsion on the mesh. If you saw fish eyes, which will lighten the emulsion coating and effect your deposit. That's a reason to degrease for emulsion. Let's put that aside for this problem.

are there some emulsions that only require a very thin coat on just one side of the screen with just one pass of the scoop coater????

is there emulsion that just will not properly expose with a 500 watt halogen light source no matter how long i expose it(or longer than i have exposed it for being somewhere around 30 minutes)????

Emulsion for textiles is very different from graphics where metal, glass & plastic don't absorb ink. A piece of photocopy paper is a fabulous stencil if you cut a Valentine heart in it, because it is on the bottom of the mesh like capillary film.

Emulsion is usually ?38% solids which means 62% water. The stencil shrinks as the water leaves and takes on the shape of the mesh and pulls into the mesh so it looks like a waffle. The stencil is in the mesh, not a film on the bottom of the mesh.

any emulsion that is fully exposed will "NOT" wash out with water no matter if you hit it with a pressure washer,or will it????

Yes a pressure washer can remove most stencils without chemical stencil remover. Properly exposed, most stencils should dissolve water and rinse down the drain.

or is there just some emulsion that is so hard core that you "must" degrease after using it and our dear friend and mentor "richard greaves" dropped the ball on this one????

Answered above.

first off i just bought this emulsion a week ago.it is a Multi-Purpose Dual Cure Emulsion that says it has "exceptional exposure latitude and ease of decoating". this emulsuion was not pre sensitized and it is blue or bluish green in color. the company that supplies it is also the name of the emulsion so that is no use to you. on the side of it it says it contains "acrylates" what ever that is... the ingrediants are water (CAS#7732-18-5), polyvinyl acetate (CAS#9003-20-7), polyvinyl alcohol (CAS#9002-89-5) , TSRN80100215-5001P (trade secret), and acrylate monomer (trade secret).

Dual-cure emulsions that use diazo are not known for their speed, but their resolution.

My light source is a 500 watt halogen work light i bought from lowes and i removed the from glass on the face of it. the light is suspended 18 inches above the screen and i have a couple layers of solid black t-shirts under the screen to prevent any reflections exposing the underside of the screen.

Good.

there is no enclosure or box around it , it is just a light over a screen. i do also have a fan that blows over the screen at a low setting to prevent the screen from getting too hot from the amount of heat the 500 watt halogen produces.

Good.

i use a 60 watt bug light i bought from lowes when i am coating my screens and i have blocked out an light from coming through my window even tho i only coat screens at night.

OK.

i have not tried to burn a image on a screen yet (well ok once.lol it washed right out) i have just been trying to get the step test to show me something i can use to determine proper exposure time, but with no avail.

Do you see color changes? Proof of ANY exposure?

the temperature in the room is not hot and not cold just comfortable. it does snow here.

those are all the factors i can think of that may help you help me.lol. thank you for taking the time to read this. i know i included alot of stuff but i feel that is the only "true" way you can help determine my problem.

thx in advance... and HEY!!! "Richard greaves"!!!! your input on this would be greatly appreciated i am pretty confident you could "shed some light" on the subject , no pun intended......ok maybe there was!!!!!

I want you to try a sample of a pre-sensitized faster emulsion & the sun, because I know it has plenty of UV.

If the Lot Number is less than a year old for the diazo, it is pretty hard to screw up stirring in the diazo, it just takes time.

Blatent Plug: Get a sample quart of Ulano QLT. Almost as fast as QTX, way better solvent resistance and resolution AND US$35 less expensive per gallon. Pre-Sensitized so never mix, never worry, never stir.

 

As much as I like work quartz halogen lamps with their APPROXIMATELY 27% IR energy, 3% UV energy and 70% visible energy - How do you know there is any UV energy in your bulb? It may be one of the many UV resistant coated bulbs.



Which emulsion? What distributor? Is it a slow emulsion or a fast emulsion. If you added diazo, that is always a slower exposing emulsion.



How long were the steps?

Dry is very important to me, but not at the top of the list. If the surface is dry, UV energy will harden it and it and you will see it in development.



So you know with that mystery diazo emulsion, 20? minutes isn't enough exposure. Do you trust the emulsion, or the lamp? You need to find out if the emulsion works. If it is sunny outside, you can use the sun make a pass/fail test and see if it can harden your mystery emulsion.



Degreasing will not effect exposure, but it will effect the surface tension of liquids like emulsion on the mesh. If you saw fish eyes, which will lighten the emulsion coating and effect your deposit. That's a reason to degrease for emulsion. Let's put that aside for this problem.


Emulsion for textiles is very different from graphics where metal, glass & plastic don't absorb ink. A piece of photocopy paper is a fabulous stencil if you cut a Valentine heart in it, because it is on the bottom of the mesh like capillary film.

Emulsion is usually ?38% solids which means 62% water. The stencil shrinks as the water leaves and takes on the shape of the mesh and pulls into the mesh so it looks like a waffle. The stencil is in the mesh, not a film on the bottom of the mesh.




Yes a pressure washer can remove most stencils without chemical stencil remover. Properly exposed, most stencils should dissolve water and rinse down the drain.



Answered above.



Dual-cure emulsions that use diazo are not known for their speed, but their resolution.



Good.



Good.



OK.



Do you see color changes? Proof of ANY exposure?







I want you to try a sample of a pre-sensitized faster emulsion & the sun, because I know it has plenty of UV.

If the Lot Number is less than a year old for the diazo, it is pretty hard to screw up stirring in the diazo, it just takes time.

Blatent Plug: Get a sample quart of Ulano QLT. Almost as fast as QTX, way better solvent resistance and resolution AND US$35 less expensive per gallon. Pre-Sensitized so never mix, never worry, never stir.

Blatant plug...use Sericol Dirasol 916 dual cure and their HD Heavy Duty Degreaser...very easy to expose and reclaim
1-800-SERICOL


Bryant

 

Yes, some emulsions will not ever expose with your lamp. Yes, especially new screens, need to be degreased. If everything washed out then you didn't crosslink the emulsion. Most emulsion manufacturers have an 800 to call for support and a list of recommended bulbs to use with their emulsions.Move the light closer and see if you have any better results. If not, you have the wrong emulsion for your lamp. Over the last forty years I have used plenty of different lamps and emulsions. The process is pretty simple and straightforward. Are you sure you sensitized it properly? Was it a powder or syrup?

Bryant

 

I am not the expert at sensitizing emulsion, but I was told to give my screens a 6 hour drying time. Even if you use a fan to get rid of moisture (and that may not help the situation), maybe your emusion has not had the time to setup properly. I use the lazy way and buy my emulsion ready to go. But then again I am small time, and only been doing this for a short time compared to the many experts available here. Good Luck

 

thanks for all the replies!!! to answer some questions and to clarify some things. the emulsion i got was from a local distributor called "tech support" working out of pittsburgh,PA. the emulsion i originally asked for was ulano emulsion cuz i used it years ago and liked it. he said to buy "their" emulsion instead cuz it was the exact same emulsion as ulano just their label on it.it doesnt say if it is "fast" or "slow" emulsion.the diazo was a "powder" i mixed with cold water . i also just want to clarify that i have just been doing step tests and havent gone past that. so the opaque-ness of my films doesnt come into play at all. so here is what has been happening i will do a step test at first started at 5 minutes and moved it 2 inches every two minutes until i ran out of emulsion on the screen. second time i started at 10 minutes and moved it 1 inch every 3 minutes. when i hit the screen after the last step test i just described my shower hand sprayer didnt remove any emulsion so thats nothing new cuz it has low pressure so i hit it with my pressure washer and started from the first step and moved in a straight line up to the top. the problem was it removed emulsion the whole way some steps easier than others.towards the top step that was exposed the longest i had to put the pressure washer real close to wash it away. so am i just getting confused cuz it washes out with the pressure washer and i automatically assume it hasnt been properly exposed??? i have not seen any indication of "fish eyes" or anything to make me believe grease/oil was left on the screen. but like i said before i dont think thats the problem cuz i havent even put any ink on the screen yet and i assume thats where most of the oil/grease comes from, and i never had degreased in the past and never had problems. i have "once" used a degreaser dish liquid but very diluted and washed it out thoroughly. but had the same affects when i tried to expose my screens after that. i made sure the soap i used didnt have any lotions or what have you. it could be that the bulb i am using is already filtered but the emulsion did have a little color change when i do the step tests. see when i tried to expose a screen with an image over it the image came out looking good , but the detail washed out and eventually so did everything else so i figured i didnt expose it long enough. so thats when i jsut concentrated on the step tests and havent expose an image since. could it be my emulsion is fine and i am getting bent out of shape for no reason just burn it to where the step in the step test matchs the rest of the exposed emulsion in color and not worry about the emulsion if it can wash out with a pressure washer??? i am just concerned cuz "greaves" said (and i trust him)that the ink has things (water) that will eat away at the emulsion. maybe i havent dried the screens long enough. its just years back when i used to dry a screen i only had to do it for like 30-45 minutes and never had a problem. so when i dry a screen for 2-4 hours i think i am over drying so..... maybe its the emulsion i can try the uv test taking it outside , but its not very sunny here.lol. i can also let it dry for 24 hours just to be safe.i can try to see if i can find a bulb that isnt made from uv filtered glass,in case that is the problem but the emulsion seems to be exposing just not fully(or so i think). and i cant imagine exposing it longer than i have which was 30 minutes and it still washing out, but it was with a pressure washer so who knows. i cant image an emulsion would react to water and wash out if it is fully exposed. maybe i am just that lucky and got that kind of emulsion. i just have seen exposed emulsion withstand a pressure washer and not wash out. so thats what i am comparing it to. called the supplier and told them my problem and they dont know. so they sent me a sample of "Ulano EX-401 ultra fast exposing SBQ photopolymer textile emulsion". havent tried it yet cuz if i can put my existing emulsion to use i would prefer it cuz it did cost me like $40 for a gallon. i know thats not that much $$$ but it is when u only used a little bit and dont want to junk it.but i will use "Ulano" from now on thats for sure!! so just so i get this straight even properly exposed emusion "can" wash out ??? cuz if thats the case than wont the plastisol and what have you eat away at it??? my brain hurts.lol.

 

the emulsion i got was from a local distributor called "tech support" working out of pittsburgh,PA.

http://www.ulano.com/dist/distUSA_NE.htm#PENNSYLVANIA
Tech Support Screen Printing Supplies is an excellent distributor.

the emulsion i originally asked for was ulano emulsion cuz i used it years ago and liked it. he said to buy "their" emulsion instead cuz it was the exact same emulsion as ulano just their label on it.

The same as what? Ulano makes dozens of diazo sensitized emulsions.

it doesnt say if it is "fast" or "slow" emulsion.the diazo was a "powder" i mixed with cold water

The product name tells me what the emulsion is. The disadvantage is that diazo emulsions are slower than pre-sensitized emulsions.

when i hit the screen after the last step test i just described my shower hand sprayer didnt remove any emulsion so thats nothing new cuz it has low pressure so i hit it with my pressure washer and started from the first step and moved in a straight line up to the top.

So, you hardened some steps. They didn't dissolve with water and rinse down the drain - Just like it is supposed to.

the problem was it removed emulsion the whole way some steps easier than others.towards the top step that was exposed the longest i had to put the pressure washer real close to wash it away.

Then you blasted the stencil with high pressure water and punched the stencil out of the mesh. This is the principle HydroBlaster taught us in the 1980's. Just pressure will blast even hardened stencil from the mesh.

so am i just getting confused cuz it washes out with the pressure washer and i automatically assume it hasnt been properly exposed???

Focus on the word dissolved. Un-cross-linked stencil will dissolve with water and rinse down the drain. Exposure changes the stencil so that it resists water and doesn't dissolve.

i have not seen any indication of "fish eyes" or anything to make me believe grease/oil was left on the screen. but like i said before i dont think thats the problem cuz i havent even put any ink on the screen yet and i assume thats where most of the oil/grease comes from, and i never had degreased in the past and never had problems.

I repeat. Degreasing has nothing to do with exposure or hardening the stencil so it resists water or chemicals.

it could be that the bulb i am using is already filtered but the emulsion did have a little color change when i do the step tests. see when i tried to expose a screen with an image over it the image came out looking good , but the detail washed out and eventually so did everything else so i figured i didnt expose it long enough.

If you are doing a manual stepped exposure test, you will be able to see when the stencil stops changing color and has reached it's saturation point.

could it be my emulsion is fine and i am getting bent out of shape for no reason just burn it to where the step in the step test matchs the rest of the exposed emulsion in color and not worry about the emulsion if it can wash out with a pressure washer???

If your image area is hard to wash out, it failed you and let UV energy cross link your stencil. Your shop conditions could allow heat or UV energy to cross link your stencil. If a dime, or a piece of aluminum foil is hard to wash out, something got to your stencil before you exposed it with your Quartz Halogen work lamp.

i am just concerned cuz "greaves" said (and i trust him)that the ink has things (water) that will eat away at the emulsion.

It is very easy for water based ink to attack the inside of an underexposed stencil.

maybe i havent dried the screens long enough. its just years back when i used to dry a screen i only had to do it for like 30-45 minutes and never had a problem. so when i dry a screen for 2-4 hours i think i am over drying so..... maybe its the emulsion i can try the uv test taking it outside , but its not very sunny here.lol.

I repeat. The surface will dry, but maybe not the inside. Since the surface dried, it will cross link with UV energy and harden, and won't dissolve with water and rinse down the drain. Later, on the press it probably breakdown during the run.

i can also let it dry for 24 hours just to be safe.i can try to see if i can find a bulb that isnt made from uv filtered glass,in case that is the problem but the emulsion seems to be exposing just not fully(or so i think). and i cant imagine exposing it longer than i have which was 30 minutes and it still washing out, but it was with a pressure washer so who knows.

Time is a very poor measure of humidity or the dryness of your stencil. Was it raining all day and the relative humidity is 80% and the screen will never dry, or do you live in Arizona and today, the relative humidity is 18% and the screens dry in minutes.

Hygrometer is the way to measure the amount of moisture in the air, thus it's ability to suck moisture out of the stencil.

i cant image an emulsion would react to water and wash out if it is fully exposed.

maybe i am just that lucky and got that kind of emulsion.

i just have seen exposed emulsion withstand a pressure washer and not wash out. so thats what i am comparing it to.

Which emulsion? Was it a different emulsion?

called the supplier and told them my problem and they dont know. so they sent me a sample of "Ulano EX-401 ultra fast exposing SBQ photopolymer textile emulsion".

EX-401 is the experimental version of Ulano QLT and you should have gotten it for free and expected to write a report.

havent tried it yet cuz if i can put my existing emulsion to use i would prefer it cuz it did cost me like $40 for a gallon.

EX-401 is pre-sensitized and will be good for 18 months from when it was made. Your diazo sensitized emulsion has the clock ticking - 4-6 weeks pot life.

i know thats not that much $$$ but it is when u only used a little bit and dont want to junk it.but i will use "Ulano" from now on thats for sure!!

Thank you.

so just so i get this straight even properly exposed emusion "can" wash out ??? cuz if thats the case than wont the plastisol and what have you eat away at it??? my brain hurts.lol.

No. Not wash out. Kicked out, with high pressure water. Remember that time you were beat up and kicked out of the creepy bar down at the docks? It is much nicer to be asked politely to leave through the front door.

Just as you use a key to open your door when you come home, you don't kick the door in. The key is so much easier. If you are in some sort of a hurry and you can't wait the extra minutes it takes to dissolve your un-exposed emulsion, those are the chances you take.

 

The amount of time you need to properly dry and emulsion has everything to do with how thick you apply it, how humid the room is, the temperature in the room, and how much air you have circulating around it. You can usually tell when it is dry to the touch on both sides. Ususally just an hour in front of a fan will do the trick.

All dual cure diazo based emulsions have different solid contents, which will affect the fine detail you can hold. 38-40% is typically best for fine lines and small halftone dots. They are almost impossible to over expose, very forgiving. If most everything washes out they are either under exposed, out of date, or never sensitized properly.

One pot emulsions are ready to use out of the box, but much less forgiving when it comes to over or under exposure. They also cost more.

Emulsion does have a shelf life. It may have ben sitting on the distributors shelf for a year and has gone bad. The bottle should have either an expiration date ink jetted on it or the box it came in. Or it may have a batch date and an 800 number to call and see if that batch date is any good.

You may not have followed the instructions regarding how to sensitize the emulsion properly. Some are syrups in a bottle that you need to add tap water to, shake well and then pour into the emulsion in the bucket and stir well, and some are just powders that take longer to melt into the emulsion when stirring well. I like the syrup better. Let it sit for an hour after stirring in the sensitizer to let all the bubbles rise to the top then scrape them all off before coating the screens. Coat the screens twice on each side to eliminate pinholes. Make the last scoop on the squeegee side of the screen. (essential)

bryant

 

ok i think i have enough information to have any chance of making this work. it sounds like i am "kicking the door open" instead of letting my key do the work. i'll give my emulsuion the benefit of the doubt and just accept that it is working fine, just need to be more forgiving of its ability to withstand hurricane force winds.lol. i'm sure i can better my drying conditions and get a dehumidifier so thats my next step. just to clear the air i am not trying to bad mouth "tech support" they are good guys and are very knowledgeable. i will definitely continue to do business with them in the future. thx Mr. Greaves. you helped set me straight now i can focus on having fun again!!!

 

There's really no need to use a pressure washer to wash out an image. Just a hose with a garden sprayer works just fine. Wet both sides of the screen first. let it sit 30 seconds or so then spray out the image. It should wash out easily in a few minutes. There's also plenty of emulsion to select from that cost less than $40.

 

I feel your pain!
I have made one successful screen in the past and have used the image for over a year. but now I need a new image but I don't seem to be having any luck! I have tried 3 times with a similar setup to what you have described and each time the images comes through but then the rest of the emulsion seems to wash away. It is driving me nuts! the first time I guess was because I used a stenciled emulsion which I guess was well out of its shelf life. so i mixed up some more emulsion but the same result! It all washes away
very frustrating indeed!

 

the first time I guess was because I used a stenciled emulsion which I guess was well out of its shelf life.

so i mixed up some more emulsion but the same result!

It all washes away

If your diazo sensitizer was fresh and "If it all washes away", the sensitizer wasn't cross-linked with UV energy.

Test a small coating of this suspect emulsion exposed with sunlight for 3 minutes. Use some coins to block UV energy and see how it washes out. If the stencil cures with sunlight, you know you have to question your lamp.

 

I accidentally exposed my emulsion to fluorescent lights prior to burning my image for about 3 mins , and I'm going to have to recoat my screens ?

 

Accidental exposure to room fluorescent light for 3 minutes



Is it safe?
Maybe your stencil now has a cured crust that may be a problem, but it depends on the factors of your room:

Distance from the lamps
Angle of stencil
Power and amount of UV-A energy the lamp radiates

40 watt Cool White ceiling lamps 8 feet away is different from Daylight lamps closer to your stencil.

Expose a bold design on this stencil right away and see what happens. Only you know what you're nervous about, but this is a problem I feel you're over thinking.

To be safe, just take the screen to the sink and dissolve the US$1 stencil with water and rinse it down the drain. Because you didn't use solvents, the mesh is ready for coating as soon as it's dry.

In your spare time, coat a small 3x5 inch area of a screen with emulsion and do a 10 minute or 10 hour test to see how safe your room light are. Then you'l have proof and wont be nervous.

http://www.t-shirtforums.com/screen-printing/t25983.html#post153633

 

Don't touch your pressure washer when you burn a screen!!!!!!! After you burn a screen take just a normal garden hose sprayer and wet the front at back, wait 30 seconds and wet the front and back again... keep repeating this process.. after about 2 min you should notice that when you wet the image it will just start to dissolve and easily wash away with low pressure water.... if the entire screen washes away it wasn't cross linked and you need to burn it for longer... to test your emulsion put it in the sun like some have suggested... that will burn it for sure if the emulsion is good

Thanks,
Jeron

 

Well I guess the 2 or 3 mins of fluorescent lights didn't effect it all at I just washed out my image with no problem thanks

 

I have been told that people coat their screens, line up transparencies, burn their screens, washout their images all under their normal shop lights... I am going to test how long my shop lights will take to affect my emulsion but haven't done it yet.. apparently the shop lights won't effect the emulsion enough to worry about it... granted this is just under normal working conditions and speeds. You wouldn't want to store coated screens out in the open because the lights will eventually get to them..

Thanks,
Jeron

 

Admittedly, I did not read all these detailed posts. I'm sure they were insightful. I'm one to cut to the chase if I can.

I tried just as you did, to use a 500 watt halogen from the hardware store, and found the exposure lacking, and full of failure. My screens washed out with 30 minute exposure times! Holey____! Oh, the heartache and despair. Actually lost sleep over it.

I then got out my wallet and COMMITED to the craft by buying a uv fluorescent unit from ryan at www.screenprinting.com as well as a nice big bucket of emulsion. I have no affinity for this company except to say the products work and Youtube is full of their helpful videos. And I'm a quick study...

Put "PRINTPRO" in the box online and save some money on your order.

I got immediate results, that meant perfect screens with no effort in 4 minutes. Stop wasting your time trying to produce with crap and relieve yourself of the pain. I use the thick side of the scoop coater, as I still lack finesse, but my resulting screens are great, and wash out with a sink sprayer, its that easy with the right equipment.

This month so far I have printed over 1000 shirts with screens from this exposure box. It paid for itself in no time.

Hope this helps you,

dANNY8bALL

 

That's weird in not a true screen printing vet , but I've been printing for about 4 years , and I'm using a 500 watt with the qtx emulsion , as well as the emulsion from ryonet and I'm burning at 12 mins with wash out of about 1 min after letting water set for about 2 to 3 minutes, and that's doing fine print as well as half times with no problem at all

 

To make yourself clear, please help us and tell what was the emulsion that failed?

What was in your big new bucket?

I ask because you might have been using a stale, slower diazo emulsion from the art store, then bought a fresh, top speed photopolymer emulsion from Ryonet.

 

The other issue I see with people using a 500w light is they don't remove the glass. The glass over the light will block 80%+ of all usable UV light. Yes the unfiltered black lights will produce quicker exposure times but the under cutting associated with those units can give you issues with high resolution images or even a slightly jagged edge when you exposure times aren't exact. I used a 500w halogen for a few years and can tell you if doing halftones I prefer the 500w over the florescent units.