advice needed with screenprinting a water based adhesive

[David Rowland]

does this glue dry to the stencil in any way?

[John Gregson]

Hi Martin,
I did this many years ago but on a hand bench not an automatic. The stencil will have to be water resistant and the pinholes dotted out with ink instead of blue filler. I think we masked out with fasson/vinyl as cellotape or gum tapes are no good. Squeegee and flood bar will have to be clean and a reasonable amount of snap will have to be used so no bubbles are left after the print. never used a svecia but when you start your ink/glue will have to be where the flood bar touches the screen first. How much ink/glue depends on whether its text or full solids. Start with a line the full length of the squeegee/flood bar, its best not to put too much on at first until your happy with the way the print is going.

A bit of a steep learning curve to go straight to an automatic, when you’ve got glue all over the place and your pulling your hair out give me a bell…..

i’ll buy the svecia off you :lol1:

[Martin Williams]

hi, I’ve not used the machine yet as been installing it and building a room for it to go into. I have got the screens which are just outlines of pictures which should when printed drop onto a conveyor belt then pass under an electrostatic flocker to apply flock to creating velvet art pictures.

[Martin Williams]

I’M NOW ON A LEARNING CURVE, DOES ANYBODY KNOW HOW TO GET GLUE OUT OF JEANS,JUMPERS AND HAIR?
HOW MUCH PRESSURE SHOULD I HAVE ON THE FLOOD AND SQUEEGE ALSO IF I AM GETTING BUBBLES DO I NEED MORE OR LESS PRESSURE

[John Gregson]

Hi Martin, :lol1: sounds like your having fun.

Bubbles left on the print could be a number of things. The glue could be too thick – thin it a bit. Not enough snap, raise your screen slightly. Your printing too fast, not sure if you can slow down an auto. Crap vac on your bed, clean holes with paper clip. Wrong angle or type of squeegee. I would use a hard, sharp squeegee with not a lot of angle – about 50
degrees.

Screen printing is a steep learning curve and every job is different.
Good luck 😀

[Martin Williams]

HI, THE MACHINE WAS USED PREVIOUSLY FOR THE SAME JOB SO SQUEEGE SHOULD BE OK. HOW MUCH PRESSURE SHOULD BE ON THE SQUEEGE AND SHOULD THE FLOOD BAR BE TOUCHING THE SCREEN OR HOW FAR OFF. I CAN SLOW THE MACHINE DOWN. WHAT DO YOU MEAN BY SNAP.I HAVE CLEANED ALL AIR HOLES AND WILL GIVE IT ANOTHER TRY

[John Gregson]

Hi Martin,
The snap (that’s what i’ve always known it as – might be a geordie term) is the gap between the stencil and the media being printed. If this machine has previously been set up for doing this then its down to the consistency of the glue. I’ve never used an automatic printer before but I would have thought that the flood bar should touch the screen when flooding/coating. If it doesn’t touch it wouldn’t flood/coat the stencil evenly ready for the next print. The pressure is all about trial and error – basically, by hand, its all about getting even pressure and letting the sharpness and angle of the blade do the work.

Cheers John

Martin – your might want to take your caps off :lol1:

[Martin Williams]

HI JOHN,
WE KEEP GETTING THE ODD ONE PRINTING OK BUT ARE HAVING TROUBLE WITH THE CARD STICKING TO THE UNDERSIDE OF THE SCREEN IS THERE SUCH A THING OF PRESSING TO HARD WITH THE SQUEEGE

[John Gregson]

right – so the print is not snapping off properly. Could be the thickness of the glue – too thick. it could be not enough snap, or it could be that you have used the wrong emulsion and the water based glue is attacking the stencil and making it sticky. Or you’ve flooded the print and some of the glue is on the underneath of the stencil making the media stick.

Have you masked the holes on the print bed out with paper that are not covered by the media getting printed ?. If you haven’t done this – do it now as it makes the vac extra strong and keeps the media stuck down on the bed.

If using a sharp hard squeegee there should be very little bend in the rubber. Yes you do have to put pressure on but not excessive, its the sharp edge and the angle of the squeegee that does all the work.

Its very hard to guesstimate what your problems are without watching you print or doing it myself. wack a video of you printing on youtube and i’ll have a better idea. :lol1:

Sorry i’m not much help on this one – John

BTW – you’ve still got your caps on on your keyboard. :lol1:

[Martin Williams]

Hi John,
I haven’t had chance to have another play yet. I don’t think the squeege is fantastic so i think i will replace it. Could you recommend a supplier to get a squeege from and what sort would you suggest. The squeege i have in is 810mm wide, 35mm long and 8mm thick, it doesn’t seem to have any sharp edges and at each end around 30mm inwards to the end it banana’s out.
The air bed is masked out. All the screens came with the machines and have been used previously. I kept getting glue coming through the screen onto the underside but i think i had far too much pressure on the squeege. It was a nightmare to keep cleaning the screen and the bed.
Thankyou for your help and advice.
Martin

[John Gregson]

Hi Martin,
Yes it sounds like your squeegee blade needs renewing as it should be straight not bent. If the wood or metal of the squeegee handle is ok then just buy the rubber, if not then buy the whole thing.

I use Colenso for my squeegee’s, screens and emulsion and Sericol for all my inks. You can get cheaper ink but I’ve found over the years that Sericols the best (personal opinion).

When ringing your order in I would ask there opinion on shore hardness of the rubber. I would get a medium G1 sharp squeegee, the softer rubber is normally used for textile printing – which would be no good for you.

Sericol: http://www.fujifilmsericol.co.uk/ff/con … ct_us.html
Colenso: http://www.colenso.co.uk/squeegee-blade.htm

Cheers John