inherited studio. need scoopcoating technique. help meeeee.
i've decided to join the gigposters forum here cause i need some help, and shall return any help as i might.
my wonderfully talented sister attends the corcoran in DC and takes screenprinting classes. she moved out temporarily and i have complete creative control of our basement studio that i built by hand, but did not finance.
here is a picture of the setup:
there is a huge florescent AWT vacuum exposure unit on the far right. under it is dark windy HEPA filtered storage for drying newly coated screens.
to the left is printing / drying area. two spots, 1 for small and 1 for large screens with hinges on flat melamine. theres a big sink/tub with spray nozzle out of frame.
i need to be taught to scoopcoat fine mesh screens.
i have a gallon of Ulano QX-1, and know the basics...here's my journey so far
i failed to get the emulsion to stick a few times. im curious as to QX-1 dry times, scoopcoating methods.
i have the victory factory plastisol and emulsion remover, and stiff brush, i used those. even with overnight drying, i get hesitant washout of the stencil, and then the whole emulsion comes off in big chunks.
i tried last time degreasing with 91% isopropyl, is there something else i can use to degrease, or is my FNG style scoopcoating method whats causing me issues?
also...for the brave, i know sheer black/white stencils are easier to expose, but of course i have some halftone transparencies id like to work with. the AWT vacuum table has 8 40W floroescent bulbs in it. with QX-1, and whatever technique makes it work, what should my ballpark exposure time be?
1. Coating Screen. Fill the scoop up, use the sharp edge against the inside of the screen pull form bottom up like in your avatar. Do the same to the back, then once more to the inside again. Don't be afraid to use a little pressure, you don't want it thick and goopy you just want to put a thin film down. How old is the emulsion? might need to invest in a new tub.
2. Shooting. After you shot your screen and begin to wash it out, is the top layer slimy? if so shoot it longer next time! If you can not wash out the image then shoot it less. You should do step test with a chunk of film to determine the best time for your set up. Or better yet call your sis and ask her! I expose on a grow lamp for 4-5 mins on white mesh and 6-7 mins on yellow mesh.
3. Halftones.. first things first! Dial in your exposure time and coating, once you got that down to a science then shoot halftones. I would make a film with assorted size dots and patterns with assorted angles and shoot and test print it to see what you can hold. Personally I prefer a larger dot like 25-15 and a angle of 22.5
Oh ok well then.... lean your screen up againts a wall or something to hold it still and tilt your coater towards the screen. Make sure you have a bead making contact the length of the screen and pull up with your hands about a a quater space apart
kinda like this...> |....m....m....|
Make sure you have even pressure and are getting an even coat.
I use QX-1 and I love that shit. Wouldnt want to use anything else except for QTX.
The step wedge test.
Print out say ... a line of type and some halftones like so
1. 12345 :::::::: """"""""
2. 12345 :::::::: """"""""
3. 12345 :::::::: """"""""
4. 12345 :::::::: """"""""
5. 12345 :::::::: """"""""
take a piece of lightpfoof cardstock or something and expose
#1 at say ... 1 minute
move the card down to expose #2 and expose another minute.
By the time you get to 5
1 has been exposed 5 minutes and 5 has been exposed 1 minute.
gently rinse out your screen to see what happens. The stuff that comes out too fast is under exposed, the stuff that doesnt come out at all is over
1. screens must be completely dry before coating
2. fill the coater 1/4 -1/2 full remove any plastic edge protector
3. Coat with the sharp side of the coater (if it has two edges to choose from)
4. If it is a ssmall screen and you can hold the screen with one hand and the coater with the the other, grab the screen on the top frame facing the coater, hold the screen by the top. It should be sideways in front of you, not flat to you.
5. hold the coater in the centre, bring it to the screen bottom ON THE MESH not the frame - it's ok to be up an inch or so. the screen is not straight up and down, it is tilted back slightly. (away from the coater)
6. with the edge of the coater even with the edge of the bottom frame, tip the coater until the emulsion is agianst the mesh all along the coater
7. Using good pressure lift the coater in a steady motion up the screen. STOP before you get to the top frame. the coater MUST run straight and not go on the frame, only on the mesh
8, when you get to the top, tip the screen more upright, at the same time tip the coater back so the emulsion stttles back in.
9. rub the coater back and forth, then lift up and away all in one motion - this stops getting blobs on the screen at the end of the stroke.
10. Look at your coat - it should be even, with no thick spots or waves of thick. If you have either of these, press harder and go smoother (no stop and start)
11. If it is way thick, do a skim coat where you don't tip the coater, you use the edge to clean the excess off.
12. Depending on your coating patter, hit that side again, then flip the screen and do the same on the other side.
13. when coating the inside of the screen, don't try to get too close to the frame or you will make a mess
14 use a flat cake batter spatula or card to scoop off and spread excess bits near the edge.
I'll see if there are some photos.
when doing coating on larger screens, you need to put a clamp on a door frame so the screen can jam under it at a slight angle. then you can hold the coater with two hands, your pressure will hold the screen still.
wow, i coat my screens EXACTLY like andymac does. that makes me feel like i'm doing at least one step of all of this in a professional manner. i also pretty much always do the skim thing on both sides to ensure a very thin but even coat.