UPS showed up Friday with everything except for my press and my foam pad for exposing. So this weekend has been an interesting learning experience and I thought I'd share.
Now that I had everything I needed to do everything except actually print a shirt, I was ready to get started. I had read, watched, read again and watched again all that I am about to do and thought I was prepared.
The first thing I did was mix the emulsion. Easy enough. Done.
Hours later, I pulled out the scoop coater and coated (1 and 1) my first screen! After letting it dry for about 5 hours, I exposed my 21 step exposure guide (21SEG). I exposed using a single shop light that houses one 250w halogen and another 500w halogen for a total of 750w of light (both bulbs on). This light source is over 20", probably closer to 25", away from the glass. I posted plans for my DIY exposure unit here on the forums a week or more ago. Although, the light distance on the plans was just a guess. I didn't actually have the light at that time.
My first exposure was for 10 mins and as soon as I started washing it out I knew it was under exposed. The emulsion peeled right off with garden hose nozzle pressure. There wasn't a solid any step on the guide. Reclaiming was a breeze.
After reclaiming, degreasing and letting it dry, I recoated (1 and 1) the screen and let it dry overnight. This morning I exposed the 21SEG for 17.5 mins. This time it did hold something and the slime wasn't present like the first time. Also no emulsion was peeling off with the hose. Things seemed to be looking better. Attached is a picture of the test results.
From what I took from this was that it was still under exposed. I couldn't determine how to adjust my exposure time due to the results of the 21SEG. So, I decided to start over.
Reclaiming was a bit more difficult, but still not actually difficult. After reclaiming and degreasing, I left the screen in the sun to dry. I then got on t-shirt forums to read about coating screens again. However this time through the posts I read something that was the opposite of what I was doing and what I thought everyone said to do.
In a thread, RichardGreaves links to information on Ulano's website about coating screens. I read over it, not expecting to read anything I hadn't already read and then I did. It said to coat my screen using the rounded (fatter) edge of the scoop coater. WHAT!! I could have sworn I had heard on video and read all over the place that you should coat your screens with the sharp edge. This site is telling me the fat edge is for first coats or wet on wet coats and the sharp edge is only used for wet on dry coatings. Wow, this is something new. If I'm misunderstanding, someone please let me know.
So, up until now, I had coated the screens with the sharp edge. I had questioned the thickness of the emulsion because it looked thin to me. As a matter of fact, that was what I was searching the forums for. On the other hand, I was thinking, what do I know, this is my first go around, maybe screens are supposed to be thin. And maybe they really are and I am really confused.
Regardless... on my last attempt for the weekend, I coated the screen (1 and 1) with the fat edge of the scoop coater and I also increased my exposure time to 22.5 mins. I'm thinking if the emulsion is thicker, the exposure needs to be longer. So I just guessed.
I wash out the image only to have steps 2 and 1 with any kind of stencil left in them. 3 and 4 had some stencil in them but they just peeled off with a rub of the finger. All steps below were all blown open. Sorry no picture of this one. I also want to point out that I rushed this screen. I used a fan and a hair dryer to speed the drying process up. Everything felt dry, but when I pressed the screen down to the glass it stuck a little. Well a lot actually. When I lifted the screen after exposure, my glass came up with it.
I take from this attempt that it is still under exposed. Mainly due to the peeling action of steps 3 and 4.
So... next my plan is to, again, coat the screen using the fat edge. (the coating looked better (thicker) to me, which seemed correct. More so than the real thin coatings I had before anyway.) Before I expose I am going to make a modification to my exposure unit and and have the light sit on something to raise it closer to the glass. I feel like it is too far away. Plus I have already exposed for 22.5 mins and didn't have what I was looking for. Any longer seems really wrong. So if I put the light closer, I'll increase the amount of light, hopefully shortening my exposure time below the 20 min mark while getting a solid step 7.
On a side note, I seem to have 'junk' in my screens. I think its dust particles and/or air bubbles getting in my screen while its wet. Are all of you guys screens perfect after coating or do the have stuff in them too? I know that these things can cause problems when printing. I guess this is something I'm going to have to figure out sooner or later.
All in all, I had a blast this weekend. I wish I didn't have to go to work tomorrow so I could work on making and exposing screens again. Plus my press is supposed to be in tomorrow and I am so pumped to print a shirt or two or a thousand. Some fun times ahead... just gotta get through this exposure issue. (btw, I know there are bad times too)
And for the curious, I only bought the 1c/1s Screen Printing Starter Kit from Ryonet. I am just testing the so called "screen printing waters". From here we'll see where I end up. I also bought an extra quart of ink, a foam pad for exposing screens and the 21 step expo guide. I noticed today that the prices for everything I bought went up. The kit alone went up $50 bucks. Looks like I bought everything at just the right time.
Ok, enough, thanks for reading.
Oh, does anyone care to share their thoughts? Thanks again.
Your exposure test looks pretty close, looks like a fairly solid 5, depending on how you washed it out. Are you running a fan over the glass when exposing with the halogens? If not, do so. I can't imagine how hot the glass and emulsion would be without it..
It also looks like you are using QTX, correct? If so, I would guess your emulsion time to be lower than 17.5 mins, but not sure. I didn't see your other post, you did remove the glass from the halogens?
Yes, use Richard's method of coating screens. As you go along, you will learn about how the thickness of the emulsion affects your prints, but for a beginner, you want to create a baseline, and the Greaves/Ulano tutorial works great.
Don't worry too much about specks of crap in your screen, unless it creates pinholes, which you can fix later, or they are large chunks that might actually screw your squeegee action up.
Don't get too focused on burning a perfect screen either. I underexposed for almost a year, and printed thousands of shirts. Once you get your press, you are going to have a whole new set of questions, lol.
Good luck and keep the patience going!
Also, you might bring your lights a bit closer to the screen. this will help with under exposed screens. 25" seemed a little far. And like the last post said. Keep the glass cool.
I also under exposed for about a year. I hated over exposing. Wasted time and money. i could work with the under exposed screens.
Another thing. After exposing and washing out the image, you should always post expose. I thing Richard once said. Do you only cook one side of your pancakes?. Turn them over in the sun or on you unit.
Good luck!
__________________
Learn what rules to follow and which ones to break. オリジナルTシャツ
Your exposure test looks pretty close, looks like a fairly solid 5, depending on how you washed it out.
There is no solid step though. The 5 is lighter than the surrounding (unexposed) emulsion. Is this still considered 'solid'?
Also, this exposure was with a sharp edge emulsion coating, not the fat edge. I assume thickness of emulsion effects the exposure time.
Quote:
Originally Posted by midwaste
Are you running a fan over the glass when exposing with the halogens? If not, do so. I can't imagine how hot the glass and emulsion would be without it.
Yes I have a small fan blowing up onto the bottom of the glass.
Quote:
Originally Posted by midwaste
It also looks like you are using QTX, correct? If so, I would guess your emulsion time to be lower than 17.5 mins, but not sure.
I'm using the CCI DXP emulsion. I agree with an exposure time being lower than 17.5 mins. I have read much lower exposure times for this emulsion. I believe its the distance from the light
Quote:
Originally Posted by midwaste
I didn't see your other post, you did remove the glass from the halogens?
Yes, I definitely removed the glass. Here's the link. DIY Expo Unit Plans...U want? I didn't actually have the light when I put these on paper. So the distance from light to glass was just a guess.
Quote:
Originally Posted by midwaste
Yes, use Richard's method of coating screens. As you go along, you will learn about how the thickness of the emulsion affects your prints, but for a beginner, you want to create a baseline, and the Greaves/Ulano tutorial works great.
Don't worry too much about specks of crap in your screen, unless it creates pinholes, which you can fix later, or they are large chunks that might actually screw your squeegee action up.
Don't get too focused on burning a perfect screen either. I underexposed for almost a year, and printed thousands of shirts. Once you get your press, you are going to have a whole new set of questions, lol.
Good luck and keep the patience going!
Also, you might bring your lights a bit closer to the screen. this will help with under exposed screens. 25" seemed a little far.
I plan to raise the light up before the next exposure test. Which will probably be tomorrow evening. I agree, 25" seems a little far and I was aware of this when building. I did buy a 750w halogen and thought maybe the extra 250w would make up for it, but guess not.
Quote:
Originally Posted by MBrhythm
And like the last post said. Keep the glass cool.
Small fan already on it
Quote:
Originally Posted by MBrhythm
I also under exposed for about a year. I hated over exposing. Wasted time and money. i could work with the under exposed screens.
I will keep this in mind. Didn't realize it was 'workable' underexposed, but it makes some sense.
Quote:
Originally Posted by MBrhythm
Another thing. After exposing and washing out the image, you should always post expose. I thing Richard once said. Do you only cook one side of your pancakes?. Turn them over in the sun or on you unit.
I did put it in the sun after washout, but I think it was too little too late at that point.
Check how hot your glass/emulsion is getting with your fan. I have a 20" pedestal fan pointing at the top of the glass 2/3 of the way up, and the glass still gets a little warm after 18 mins.
Quote:
Another thing. After exposing and washing out the image, you should always post expose. I thing Richard once said. Do you only cook one side of your pancakes?. Turn them over in the sun or on you unit.
I am a little unclear on this, as Richard has also said that when you wash the emulsion out, chances are you also washed all the remaining diazo out of the remaining emulsion, and post-exposure is futile.
I am a little unclear on this, as Richard has also said that when you wash the emulsion out, chances are you also washed all the remaining diazo out of the remaining emulsion, and post-exposure is futile.[/QUOTE]
When i first started out, I was exposing with 500w MH light about 30" away. I was getting usable screens. And I was always post exposing. But one time I was rushing late at night and forgot to post expose. After printing the 3 color job, I cleaned the ink with ink remover. A few days later I went to reclaim the screens and nothing.... The emulsion had cross linked. It was locked. No way to remove it. Even put the pressure washer on high and tried blasting it out.. NOPE! Wasn't coming out. I had to rescreen all 3 screens. Searched around. Posted a few questions. Realized I forgot to post expose. That was the one step that I needed to do.
__________________
Learn what rules to follow and which ones to break. オリジナルTシャツ
When i first started out, I was exposing with 500w MH light about 30" away. I was getting usable screens. And I was always post exposing. But one time I was rushing late at night and forgot to post expose. After printing the 3 color job, I cleaned the ink with ink remover. A few days later I went to reclaim the screens and nothing.... The emulsion had cross linked. It was locked. No way to remove it. Even put the pressure washer on high and tried blasting it out.. NOPE! Wasn't coming out. I had to rescreen all 3 screens. Searched around. Posted a few questions. Realized I forgot to post expose. That was the one step that I needed to do.
Alright, you've lost me now. Exactly how do you post expose? We're talking putting the screen, after washout, in a UV light source (the sun lets say), to make sure all the emulsion is exposed. Correct?
Also, isn't crosslink what happens when you expose the emulsion to UV light?
Yeah! you are right. But if the emulsion is not exposed right, it can lock. Then when you use emulsion remover it doesn't work.
If exposing on a sunny day, I'll use the sun to post expose. At night I use my exposure unit to post expose.
Sorry for being unclear. Just woke up. I'm in Japan.
Sorry
__________________
Learn what rules to follow and which ones to break. オリジナルTシャツ
First Weekend... 
