"He who marches out of step hears another drum." ~ Ken Kesey
No you need to have firm pressure on the coaters edge at all times both sides. Your not trying to create the actually thickness like taping drywall. Every time you make a pass with the coater it leaves a certain amount of emulsion then when you finish up on the ink side all the emulsion is pushed to the shirt side creating the thickness.
I will agree with Mike in that you need more pressure. It may take more strokes to get your stencil but you'll have more consistency and better stencils overall if you use the same amount of pressure and keep everything as uniform as possible. Just gliding the scoop coater over the mesh leaves too many things that could affect the thickness of the emulsion deposit. Viscosity and solids content, along with temperature and flow characteristics of the emulsion will start affecting stencil thickness instead of number of coating strokes, speed and pressure. You're just inviting a few more variables into the equation in my opinion by doing it that way.I'd not add or decrease pressure on the first or last and just keep everything the same throughout so when you do get to where you can start measuring you'll have more consistency and that is key to stencil thickness once you have the thickness you want.
I am going to go out on a limb and assume Pierre was exaggerating how hard to push. And yes firm pressure is important, as Pierre stated enough to hear a little creaking is good.
Your guys are all nuts. Pushing hard enough to break the screen? Firm pressure is fine. If your screens are flat and your mesh is tight then all you need to do is put enough pressure so that the blade of the coater is tight against the mesh. I coat 10 to 20 screens at a time and if I was pushing as hard as your guys are saying I would be worn out after doing them. I coat fast 2/1 with the sharp side. I get a nice 12 to 20 EOM depending on mesh count (give or take 3% to 4%). Stencil thickness is important. I know there are tons of ways to do everything but pushing as hard as some of you is way over kill. Consistent firm pressure with consistent speed is key. Also check your screens. I hold a screen up a light to check thickness and smoothness of the coat. If you hold the screen up to the UV safe light you will be able to gauge the thickness of your emulsion depending on mesh count and color of mesh. I have been doing this for a while and can tell when I am too light on the emulsion or too thick. Its not a perfect way of doing it but it does give you a small level of quality control before the screens are dry. If you see the screen has light and dark areas just redo your coating on that screen. Then check it again.
Quote from: Screened Gear on May 30, 2012, 01:27:46 PMYour guys are all nuts. Pushing hard enough to break the screen? Firm pressure is fine. If your screens are flat and your mesh is tight then all you need to do is put enough pressure so that the blade of the coater is tight against the mesh. I coat 10 to 20 screens at a time and if I was pushing as hard as your guys are saying I would be worn out after doing them. I coat fast 2/1 with the sharp side. I get a nice 12 to 20 EOM depending on mesh count (give or take 3% to 4%). Stencil thickness is important. I know there are tons of ways to do everything but pushing as hard as some of you is way over kill. Consistent firm pressure with consistent speed is key. Also check your screens. I hold a screen up a light to check thickness and smoothness of the coat. If you hold the screen up to the UV safe light you will be able to gauge the thickness of your emulsion depending on mesh count and color of mesh. I have been doing this for a while and can tell when I am too light on the emulsion or too thick. Its not a perfect way of doing it but it does give you a small level of quality control before the screens are dry. If you see the screen has light and dark areas just redo your coating on that screen. Then check it again.I wish I could measure the actual pressure I'm applying to the mesh when coating but I'll just have to guess at it being around 6-8lbs and I don't hear any crackling or popping noises of the mesh, just the sound of metal gliding across mesh at around 10"/sec.Are you getting 12-20 "%" EOM or 12-20 "microns" EOM with the sharp edge? I've compared both edges a lot over the years and will continue to do so every once in a while but the rounded edge has always worked better for us, especially when getting into the thicker stencil needs. I'm shooting for 20% EOM for 156-205 and 12-15% for 225-330, 30% all the way up to 50%+ for some of our 83-140's. I can build a thick stencil with the sharp edge but it takes a bit more work so we have always used the rounded edge for every mesh count and every stencil thickness we were trying to achieve. I am going to go out and try to coat a screen with the Saati PHW Red and the sharp edge of the coater on some low mesh counts and I'll report back here as soon as I can. Is there any reason why you like the sharp edge versus the round?