# First time silk screening problems



## kornwallace8 (Jun 5, 2013)

Howdy- I have recently attempted to venture into the world of silk screening with very little money and have been trying to cut corners any way possible with little luck. 

I am using a 250 watt bulb to expose my image in a pitch black room(but very humid room; I attribute the humidity to the exceptionally long time it takes my emulsion to harden as well- but I could be wrong)- but after 15 minutes of exposure I attempted to wash the screen out in the shower and the image was only slightly revealed. I then bumped the exposure time to almost double, constantly shifting the light to zero in on certain regions of the screen- I then immediately took the screen to the shower and washed it off with cold water, exposing the image and then using a tooth brush to reveal the image. After using a tooth brush- half of the image was exposed and the other half appeared to be quite firm and fried onto the screen- it took emulsion remover to penetrate it. 

I was hesitant to post this because I am well aware that very few people on this forum have little money and are more than capable to dish out funds for high-tech equipment- I cannot and would greatly appreciate it if someone had any insight as to how I can make my set up work.


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## sandhopper2 (Apr 26, 2010)

I have not tried this , but some say you can use the Sun to expose a screen . I don't see how 250 watts will do it . I have used a 500 watt halegen work light at 18 inches above the screen and got good exposure in 6 minutes . I found a professional unit on C list and now expose in 1 minute 
good luck keep trying and you will find what works for you 
Larry


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## PiPsodin (May 14, 2012)

I use one 1000W and two 500W on both sides - exposure time 1,30 min plastic, 1,15 - 1,20 textil!


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## moe_szys1ak (Jun 16, 2008)

kornwallace8 said:


> after 15 minutes of exposure I attempted to wash the screen out in the shower and the image was only slightly revealed. I then bumped the exposure time to almost double, constantly shifting the light to zero in on certain regions of the screen


Right there is probably the source of your problem. If the emulsion isn't washing out, you're exposing for too long. And you shouldn't be moving the light around. The light should be centered above the image at the same height as the longest diagonal length of the artwork. For example, if the longest distance from corner to corner in the art is 10 inches, then the light should be suspended 10 inches above the art.

After you get that set up, instead of doubling the 15 minutes, halve it and try that. If it still doesn't wash out, go lower. If it does wash out, but too much, go a little higher. You'll probably have to do it a few times to get it right. Or, better yet, do a step-wedge test (do a search here on TSF and you'll find a million step-wedge how-tos), or buy an exposure calculator and use that to determine the best exposure time for your setup.


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## kornwallace8 (Jun 5, 2013)

Thanks Moe, I am still fairly hesitant to continue this screen printing venture after failing 5-6 times and not having adequate funds to make so many mistakes.


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## mustangFWL (Feb 27, 2012)

The big problem you are having is trying to cut corners.. 

The best thing you can do that is free is to go to youtube and watch videos produced by CatspitProductions..
He will walk you through everything.. 

Then after that.. you need to go to a good supplier and purchase a hobby kit.. there are a few sellers out there that have a kit for 200... that will get you everything you need to do to get started cheaply without cutting many corners.. 

Like Moe said.. do not move your light source when exposing... that is a bad thing to do.. it causes uneven exposure like you mentioned..

What type of emulsion are you using?

Did you properly clean/degrease you screens before coating with emulsion?


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## kornwallace8 (Jun 5, 2013)

I am using Diazo/ Speedball emulsion and sensitizer. 

I did not degrease....
nor do I have a piece of glass to lay over the image- is this an important factor? I could take one of my windows out to use the glass but there are plenty of blemishes, some of which I am sure wouldn't come out.


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## mustangFWL (Feb 27, 2012)

Well a properly cleaned screen is the first part in getting a good burn... if you just took the screen right out of the box and coated it with emulsion.. you were doomed from the start...

The glass is a great idea due to the fast that it presses the image down onto the screen, keeping the screen and the film in contact to eliminate any blurry edges...

Which side are you burning the image into? The sub-straight side or the ink well side?

I have no experience with the speed ball emulsion.. but with your light source.. I would take a guess at the light being 10" from the top of the image, for about 15 minutes.. the good thing with the Diazo emulsions is that you do have a decent amount of play time from having an under exposure to an over exposure..


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## kornwallace8 (Jun 5, 2013)

OK gang, thanks for your help- attached is an image of test run #66. Image taped securely to screen with glass laid over it- 250 watt bulb 10 in. above and exposed for 15 min. in previously pitch black room then washed out in shower with cold water...

Text washed out slightly in corners- yet image is quite dark and I am almost certain it cannot be removed with only water- therefore not usable....


[media]http://i6.photobucket.com/albums/y208/kornwallace8/Photo81_zps6ee8b134.jpg[/media]


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## mustangFWL (Feb 27, 2012)

That looks like it is well underexposed.. Does the emulsion feel slimy on the ink well side of the screen?

Did you clean it correctly?

How are you coating the screen?


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## Omni (Mar 28, 2012)

Kornwallace....Welcome to screenprinting....Don't give up......A 250 watt bulb?.....Is it a regular lamp bulb? or something else.....If it is a regular lamp bulb, then there is your problem.......No UV light......I have a few more questions.....What is your art film positive made with ? Depending what your positive is: you can use the sun to expose screens.....I do it all the time and get excellent results......Also, there are a few other light sources that you can get on the cheap to expose screens.......Feel free to reply here and I would be delighted to guide you on how to use the sun for free, and get some kick-*** screens fast.....Much of that will depend on what kind of film positives your are using.....I also use a 400 watt metal halide with a ballast, but that may be more money than you want to spend, but if you get serious about screen printing on the cheap, it is a fairly low cost investment to get predictable results......There are a few other cheaper alternatives as far as light sources go, so feel free to inquire.....A lot of guys here use relatively inexpensive light sources and get good results, so the answers are here....


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## c3turner (Jun 3, 2013)

i tried and falied my first time too lol


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## kornwallace8 (Jun 5, 2013)

Hi Omni- thanks a lot for bearing with me. 

I am using a Philips 250 heat light Clear BR40 bulb with a ballast and my image is on HP transparency paper.


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## Omni (Mar 28, 2012)

Heat bulbs are not high output in the UV wavelength required to expose diazo emulsion (they kick out infra-red wavelength primarily) plus the heat generated could have an adverse effect on your emulsion......Not sure how much you paid for it, but you can google Tanning lamps BR40 and Grow Lights BR40 and get a bulb for about 20-30 bucks in your wattage.......They emit a wavelength of UV that will get you into a workable situation on the cheap......I would also recommend step wedge exposure testing or some other form of exposure testing films available throughout the industry....(check this forum for info on that)....You might even find a 250 Metal Halide BR40 that would get you there.....Since you already have a 250 watt ballast......Check out WW Grainger.......There are all kinds of Light Bulb Direct companies out there......Home Depot and Lowes have a nice selection of lighting....Home Depot is where I got my last bulb from, so you might find a 250 watt BR40 there....Garden Supply stores might be another source......Home Depot....That is where I would start........Also be sure to be aware of the position of your bulb/ballast configuration, as some bulbs only use horizontal, some vertical, and some universal mounting positions and get a bulb for your particular set up.....I see a lot of printers here using Halogen lamps, to which I cannot speak, as I have no experience with them....Perhaps someone may chime in here and give you insight on those type of bulbs......Currently I have a 400 watt Metal Halide configuration with my light at about 36 inches from my screen......I use this distance for a variety of reasons including heat dissipation and the versatility of screen size......I do experience longer exposure times, but in my set up there is good reason for that......Some may say this is a waste of time, but I do other things to be productive during my longer exposure times and get excellent Halftone results with this set-up..... I still do use the sunlight for other projects as well.....When I use the sun to expose screens, here is what I do.......My films of the past were Litho films that I shot in my darkroom......Not computer Inkjet prints.....What I do is spray a light mist of spray adhesive to my film.....then tack it onto my screen.......Back the image with a sheet of Black paper on squeegee side, then take it out into the sun with film facing the sun.....45 seconds to 1 minute and 1/2 depending on how thick my emulsion is.....the time of day and the intensity of the sun, (can even burn screens on a slightly cloudy day)...You can watch the color of the emulsion change as you expose......I also hold a finger on my emulsion around the edge of the screen then I can lift my finger to reveal it and see the difference between the exposed emulsion and that which was under my finger.......This technique takes some experimentation but you can afford to overexpose a little as you watch the screen get darker in the sun.....up to a few minutes.....After I feel right about it (instinct).....back to the screen room (you can use yellow bug lights in your screen room which won't effect the emulsion, and see more of what you are doing rather than to work in total dark ).....Peel film off screen and clean spray adhesive off with small amount of mineral spirits and rag.....then proceed to wash out......Use a hose with a multifunction nozzle that gives you a variety of pressures of water....I prefer Flat setting....Shower is not quite what you want to use......With the spray adhesive method, inkjet printed films will probably get wasted so you may want to print a spare film or paper....With Lith Film, I did not have this problem.....Currently, I use an Epson 1430 Inkjet, so the need to print spare films is inherent in this process, especially if you get re-orders......And you can do multi-color work this way...
It is what it is, and it will work....You could attempt to hold the positive to the screen with glass between your fingers and the screen or Jerry rig your glass and a couple of C clamps and wood strips if you have an engineering aptitude, being careful with your pressures taking your time to set it up in your yellow buglight lit room, where you can see.....before going out into the sun......Lot's of effort to get a screen, but I can tell you from experience that I have gotten some of my best exposures from the purest form of UV lite.....The Sun.....and also get a kick out of the whole process.....and that's cool.....Omni


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## gendoboy (Jan 4, 2013)

I expose for 12 to 13 minutes. When I wash out my stencil, I usually get the emulsion wet and let it sit for like 2 minutes before I put anymore water on it. Then crank up the pressure and let the stencil have it. Seems to work for me every time. Remember, the more water you put onto your emulsion, the more detail you will loose. It's better to let it just sit while its wet to let the uncured stencil soak up the water.


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## kornwallace8 (Jun 5, 2013)

Thank you OMNI! I used my man (the sun) and it worked- now time to experiment. I am very grateful you shared these tips with me- I will tell you how it goes!


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