help!! ...anyone got any ideas whats happening here?

[Douglas Walker]

had to abandon the 3rd run on this print due to quite a large area at the top of the print not printing correctly... the mesh all looks ok - and i cant see where the problems coming from...




and more visible with the flash off...



the mesh does seem to ping back fine, although the area shown above does seem to be a bit 'sticky' in snapping back. the inks starting to clog on the mesh in this area

i THINK it seems like its lifting the ink back off the sheet, rather than the ink being blocked from passing thru the mesh in the first place

ive tried cleaning up, and applying emulsion remover to the area - just in case there was a faint trace of emulsion in the mesh, but still the exact same results

i'll try raising the snap/off height later today and see if that helps (cheers, spence!), but kinda resigned to scrapping the stencil and re-doing...

printing in a home workshop when its minus 6 outside isnt helping this either - and its too cold to have problems like this!

any ideas/help/advice appreciated

[kim_a]

Looks like a hickey, which is what happens when the ink makes the paper stick to the screen after your pull. If you had checked the last week of threads, you would have stumbled upon this, which looks very similar to me so I suggest you have a look and see the advise there:

What is making this weird line appear? Is the ink cracking?

So, more off-contact, thin the ink, etc.

-Kim

[DenisMutter]

how's the speed of your pull?

[standard]

You need to dehaze the offset with a discolorant.

[Andymac]

Looks like a hickey, which is what happens when the ink makes the paper stick to the screen after your pull. If you had checked the last week of threads, you would have stumbled upon this, which looks very similar to me so I suggest you have a look and see the advise there:

What is making this weird line appear? Is the ink cracking?

So, more off-contact, thin the ink, etc.

-Kim

This is it, nothing to do with your stencil.

do you have a vacuum? this happens when your paper sticks to your mesh (lifts) or your mesh is slack and sticks on your paper, then pops off.

have you raised your lift? If this is at the top of your screen, shim up your frame where they sit in your clamps

If you have a bigger screen, turn you image slightly, so when you are starting to pull, the squeegee starts in the corner, not against the whole side edge - it's less sticky coming across the corner, and allows the paper a chance to stay stuck to the bed. When you hit a large area straight on, the stickiness of the ink lifts the paper all at once and won't let it release.

You can get the same effect by angling your squeegee a bit at the start of the pull, then straighten out.

You are right about the ink staying in the screen, and then blocking - when you don't clear the screen on a pull, or it stays stuck to the screen because you don't have vac pulling it down, the ink will stick to the threads, after a print or two, more ink sticks, and your screen starts clogging.

If you have a vacuum and this thing keeps happening near an edge, take a sheet of stock and after you put you paper down, overlap the stock slightly over the edge. You have to leave vacuum under this flap too to keep it down, or tape it in place. this makes the print paper stay flat and tricks the screen into thinking it is printing a larger piece with bigger margins.

[andy_schmidt]

you need to weez the juice

[Douglas Walker]

This is it, nothing to do with your stencil.

...If you have a vacuum and this thing keeps happening near an edge, take a sheet of stock and after you put you paper down, overlap the stock slightly over the edge...

i'll try out this and raise the snap/off height along the edge nearest me... (im printing this the wrong way round as ive really small text at the foot of the print, and i find i use a bit more pressure at the start of a pull & seem to hold small detail that bit better) ...the problems at the end of each pull, and it WOULD be near the edge of the vaccum area. i'll maybe clean out the holes in the bench surface with a pin around this area, just in case the holes in the bench surface are clogged wi' ink & crap

now THAT sounds like a great job after just finishing shovelling snow fer two hours... i'll start back printing this afternoon and see how it goes

thanks for everyone's time on this - much appreciated

[mikeage]

i think steve recommended to me once that i use a more opaque color, that adding white if possible would help.

[paul204]

you need to weez the juice

I think this would def help

[Douglas Walker]

printed the blue run late this afternoon... and all perfect now

the edge of the print was near the edge of the vacuum area, so shifted the clamp bars up the bench so that the screen was more centralised on the vacuum area, raised the snap/off height & unblocked some clogged air holes

once a run is underway and going well, it's then easier to see any smaller problems... and noticed my board has a slight moisture buckle in it with being taken in/out of the workshop/house (just been way too cold overnight just to leave in the 'shop - minus 13 tonight apparently)

http://www.handcookedposters.com/wp-...s/DSC02574.JPG

even though the buckle is really slight, it was just enough for the board not to snap down tight with the vacuum - so a light press down along two edges once the vacuum was engaged did the trick - paper held tightly in place

thanks again, people - and remarkably enough, no juice required any weezing at all ...wtf?