Hi I am just getting started at screenprinting I bought some used equipment and now I am trying to figure it all out. I have unsuccessfully tried to burn screens for about a week now. I am not quite sure what I am doing wrong I am using a homemade exposure unit with 500 watt lighting under glass I have tried burn times anywhere from 1 minute to 3 minutes previous owner said he exposed for 1 1/2 minutes, anyway I get a ghost image when i am rinsing and that is about it! My garage is really hot would that effect the screen when emulsion is drying? Or could my emulsion be bad? It came with the equipment but looked like it was brand new so I just started using it the other problem could be my exposure time I read that if the emulsion rinses away that it is underexposed which is what happens after 1 minute of exposure it does not rinse out at 1 1/2 minutes but neither does my image. Any help would be greatly appreciated. Thanks in Advance
Kelly
Your emulsion could definitely be bad. It doesn't have a long shelf life if it isn't refrigerated, and if it came with the used equipment, my guess is it hasn't been used in quite some time. If I were you, I'd buy some new emulsion and do a step wedge test to determine the correct exposure time.
well it could be several problems, how old is the emulsion first, emulsion will last about 6 to 7 months if keep in the fridge, not the freezer of course. two i think the time the image was burned is to short, i have about the same set up and it takes me about 6 minutes to burn my image at about 15 inches high. see if you can find out how old is the emulsion f he cant tell you maybe you should buy a new one, then try to burn, good luck.
I had a similar outcome about 2 weeks ago. I was keeping the screens in the garage after coating. I live in Memphis,TN and that is particularly important. In a post about a week ago, search for it here on the forums, someone went into complete detail about the effects of moisture and humidity on the screens as they are coated before exposure. I will attest to this. I used to keep my screens in the house in a large box after coating. Then I moved them into the garage....and for the life of me I saw the image but could not get it to wash out for nothing. Ok, enough rambling....here is the solution that worked for me. If you keep them in air conditioned area it will eliminate some of the moisture from humidity in the screens. After I moved them back inside and then burned them...PRESTO!! It worked like it did in the old days when I started. I have came to the conclusion that either purchase a dehumidifier or keep the screens inside in the air conditioning until I expose them. I tell you it was very frustrating and now because of the post I have been successful again! Try moving them from the garage, new emulsion and burn them the 1.5 minutes as the previous owner did. Myself, I use an exposure unit - a wise investment in my mind for a startup operation. You have to get your screens burned consistently and correctly. I am not a big fan of home made and engineered exposure units....but the cost is good I suppose so I don't want to knock them. Try to keep screens in the air conditioning and see if that improves.
Is it a 500 watt hologen? If so, 1-3 minutes isn't nearly enough time. Most people go 12-16 minutes. I have a 500 watt halogen and actually expose for 45 minutes, but I'm the exception because nothing about printing follows the rules in my shop.
I had a similar outcome about 2 weeks ago. I was keeping the screens in the garage after coating. I live in Memphis,TN and that is particularly important. In a post about a week ago, search for it here on the forums, someone went into complete detail about the effects of moisture and humidity on the screens as they are coated before exposure. I will attest to this. I used to keep my screens in the house in a large box after coating. Then I moved them into the garage....and for the life of me I saw the image but could not get it to wash out for nothing. Ok, enough rambling....here is the solution that worked for me. If you keep them in air conditioned area it will eliminate some of the moisture from humidity in the screens. After I moved them back inside and then burned them...PRESTO!! It worked like it did in the old days when I started. I have came to the conclusion that either purchase a dehumidifier or keep the screens inside in the air conditioning until I expose them. I tell you it was very frustrating and now because of the post I have been successful again! Try moving them from the garage, new emulsion and burn them the 1.5 minutes as the previous owner did. Myself, I use an exposure unit - a wise investment in my mind for a startup operation. You have to get your screens burned consistently and correctly. I am not a big fan of home made and engineered exposure units....but the cost is good I suppose so I don't want to knock them. Try to keep screens in the air conditioning and see if that improves.
I saw a video online of a guy who uses a hairdryer on his screens right before he exposes them just for that reason- to reduce humidity. Seems like a good idea as long as you don't heat it up too much.
Also make sure that your vacuum table is sucking down all the way. You can easily lose the edges of the image or lose the image all together if it's not working properly
Having trouble burning screens 
Re: Having trouble burning screens 
