>>> On 9/23/02 1:35 PM, "Bruce" <smthopr@...> wrote:
>>> has anyone tried using a silk screen squeegee, but without the screen?
>>>
>>> -Bruce
>> From: "Robert Morrison" <rmorrison@...>
>> Doesn't work. Screens produce enormous shear resulting in a major foaming
>> problem with thin liquids. You have to use a thick body product or a lot
> of
>> antifoam to get rid of the foam...this requires formulating the likely
>> polymers for a method of application much different than what they were
> made
>> for...or risking the poor film qualities of polymers dosed with anti-foam.
>
> On 9/24/02 2:05 AM, "Ernst Dinkla" <E.Dinkla@...> wrote:
> Correct, but depends on the speed of printing, the mesh and the number of
> prints.
> Something has to be added: inks with water, alcohol or glycol as the
> solvents are much more prone to foaming than the usual solvents or no
> solvent as in UV curable inks.. The addition of antifoaming agents is 1%
> weight at most, I have not seen problems as a result of that. And it is
> possible to print large prints in silkscreen something I see not possible
> with a rod. A3 will be no problem with the last though. I guess a vacuum
> tabletop will be nice for keeping the paper flat when using a rod
> applicator.
>
> Ernst
>
Right, but I think the application that most people are talking about here
is simply using a screen with a squeegee "at home" or in a non-ventilated
studio. My feeling is that a screeb is extremely unlikely to work with
anything that people would be able to handle in an environment not set up
for dealing with solvents. I have no doubt that a commercial screen printer
could get acceptable results if a ink company set out to formulate an
overcoat for this application. I recently saw some prints coated with silk
screen, but the client rejected them because of yellowing and how brittle
the paper became...but of course this was just with one tyep of overprint
varnish (which was solvent based and UV curable). The problem, as far as
I've been able to tell is that this is a niche market and most people don't
want to be dependent on someone else to do the coating of their prints. But
I certainly could be wrong.
As far as the rod goes, I think the practical size limit for someone working
at home/studio is 24 x 36. I've recently coated a bunch of prints that
size. If you work with heavy paper (around 300gm) the paper stays
relatively flat, although a vacuum table would be great if you were really
setting up a production line. Rod coating is obviously used for much larger
applications than this, but I think a print larger than 24 x 36 would
probably require a machine built for the purpose. I've considered this,
going in with a prepress to offer the service.
Robert