Silk screening...
Spehro Pefhany
> Has anyone here made silk screens for their own front/rear equipment panels?
> If so, how did you go about it?
It depends where you want to start, if it's with wood and fabric, you have
to stretch the fabric and attach it to the frame, cover the stapes with
waterproof tape. Fabric is usually polyester, not silk, various meshes
are available. Bigger meshes give you thicker coating, all other things
being equal, but poorer resolution.
Then you coat the screen evenly with emulsion, allow it to dry in the
dark, expose it in a vacuum frame (preferably) or a contact frame with a
positive film of what you want to print. Vacuum frames for screen
printing have a special deep blanket.
Then it is developed with water. Carefully touch up any bad spots
manually, either painting screen block on or opening up holes with a
needle. If it's for one-shot use, ordinary office tape will work for long
enough in most cases to mask the ink off if you put it top and bottom
and avoid rubbing the squeegee over it.
The emulsion polymerizes where the light (usually UV or halogen)
hits it. After it dries you can use it, though for some solvent systems an
additional baking step (hardening) is advisable if you want much life.
You want positive right-reading with emulsion up for the film, since it's
exposed from the printing surface. If you are back-printing then it is
reversed, of course.
These days, I usually go to a top notch graphics place and have it done
(not a Tee shirt hack place.. avoid at all costs). They charge about
US$50-75 for making a high quality screen from 1:1 litho film. Any large
city will have at least one place like this (and many, many crappy ones).
Best regards,
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany --"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Contributions invited->The AVR-gcc FAQ is at: http://www.BlueCollarLinux.com
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Greg Neff
David Milne <dmi...@camtech.net.au> wrote:
> Has anyone here made silk screens for their own front/rear equipment
panels?
> If so, how did you go about it?
>
> --
> Regards
>
> David Milne
> ICQ 37590068
>
>
If you have a good relationship with your PCB house, you might be able
to get them to do it. They will use the same process as used for the
component reference designations on PCBs, and the quality will be
pretty good. If you really sweet talk them, they will even bake the
panels afterwards. This is a good approach for low volume stuff, such
as prototypes and testers.
BTW, find a sheet metal house that has a laser cutter. You feed an
AutoCad drawing file in one end, and then you get a plate with all your
cutouts from the other end. This saves on setup charges associated with
CNC punches, and you don't have to match your cutouts to the dies that
the fabricator happens to have in house.
For significant volumes, talk to your sheet metal fabricator. They
will point you to good sheet metal plate/paint shops, which should also
have screening equipment.
--
Greg Neff
VP Engineering
*Microsym* Computers Inc.
gr...@guesswhichwordgoeshere.com
Sent via Deja.com http://www.deja.com/
Before you buy.
Douglas W. Jones,201H MLH,3193350740,3193382879
by David Milne <dmi...@camtech.net.au>:
> Has anyone here made silk screens for their own front/rear equipment panels?
> If so, how did you go about it?
> Or, do you know of a website that describes the processes involved?
I learned silkscreen printing in art class in highschool, back around 1966.
You begin with a screen, traditionally made of fine silk cloth, but of
course, nowdays, a synthetic is used. Fine nylon stockings are too coarse,
but close. Most art supply stores sell silkscreen fabric.
Then, you mount the screen on a frame. Typically, you mount it on exactly
the same kind of frame you'd use for canvas on which you intended to make
an oil painting, using exactly the same method, pulling the fabric very
to make sure it's dead flat.
Then, you coat the fabric with silkscreen varnish in all places you don't
want to get ink in the final print -- that is, you varnish the negative of
your final artwork. There are at least 4 ways of doing this:
1) photo-polymerizing varnish (not too different from photoresist made
for printed circuit boards). If your final artwork is black lines on
white, expose the varnish through a positive of the artwork, develop,
and wash out the areas where it wasn't exposed. Art supply stores
sell the resist.
2) negative photo-resists. More complex than 1. Your resist ends up
on the areas where you want nothing, and it serves to resist the
adhesion of the final stencil (typically a varnish or shellack) to
the screen. Then you dissolve away the resist and mechanically
remove the varnish film where it didn't adhere to the screen.
3) Use tempera paint to directly draw on the screen the positive of what
you want to print, then shellack over the whole thing from one side
only. After the shellak dries, use water and a soft toothbrush to
wash out the tempera paint and remove the shellack that didn't stick
to the screen because the paint was in the way. This is the classic
way to make a silkscreen print.
4) Use shellak or varnish to directly paint the negative of your artwork.
No matter how you make your screen, you print it by putting a dollop of ink
on the screen (off to one side), and then putting the screen over the
surface you intend to print (T-shirt, instrument panel, you name it). To
finish the job, you use a squeege to firmly draw the dollop of ink across
the artwork, forcing the ink through the screen wherever the varnish or
shellack isn't in the way.
Doug Jones
jo...@cs.uiowa.edu
Harry H Conover
: Has anyone here made silk screens for their own front/rear equipment panels?
: If so, how did you go about it?
: Or, do you know of a website that describes the processes involved?
Dave, here's the process I (and many other use) in a nutshell.
(This is the classical method used by PC board producers and equipment
manufacturers. Unless you're a purist, it's a bit of effort to do for
a single piece.)
1. Prepare a full size artwork of the information you want to
silkscreen onto the panel.
2. Have the graphic artwook photographed using a lithography
camera and obtain a 1:1 negative. (Many printing shops can
do this for you at a nominal fee. ($6.00 for an 8x10 negative
or something like $10.00 for an 11x14 is about the going rate
IIRC.)
3. Contact print the negative on what is generically known as
"carbon tissue" (Hi-Fi Green and Hi-Fi Blue and typical
brand names. This is a light sensitive material that you buy
in sheets or a roll from a graphic arts supplier. (I believe
that Nazdar is the name of a major mail order dealer for graphic
arts and silk screening supplies. You will need a UV exposure
frame similar to that used for making printing plates to
expose it, or sunlight may work.
4. Develop the carbon tissue (typically using a weak solution of
hydrogen peroxide in water), and carefully place it gelatin
side down against the OUTSIDE of a silkscreen previously
stretched on a wood or metal frame. The gelatin sticks to
the screen material. Peel off the carbon tissue backing per
manufacturer's instructions.
5. Use masking tape to block out all portions of the screen not
covered by carbon tissue.
6. Mount the frame in a pair of silkscreen hinges attached to a
sheet of 3/4" plywood, and use thin positioning strips of
plastic of PC board stock to hold the item to be screened in
a fixed position.
7. Carefully align the screen with the work using adjustments
usually found on the silk screen hinges. Register the postion
of the screen to the work -- index marks on the artwook help.
8. Coat the insider of the screen with the paint that you are going
to use, and use newsprint layed on top of the item to be screened
until you have got the feel of using the squeegee, which takes
some practice. Once you are getting good, clear impressions,
omit the newsprint and screen the work surface.
9. If doing a number of pieces, work quickly because the silkscreen
type paints tend to dry quickly and clog the screen when you work
tool slowly.
10. Keep a good quantity of silkscreen paint solvent on hand and
when you screw up a piece, clean it with the solvent, let it dry
and try again.
11. When the run is complete, carefully clean both the screen material
and carbon tissue stencil for storage. You can even remove the
stencil to prepare the screen for use with a different stencil at
a later time.
12. There are businesses that will prepare the finished silkscreen
with a permanent stencil mounted on a screen in a frame, if you
don't want to go through the learning curve.
Hope this helps.
Harry C.
p.s. It may be possible to produce an artwork negative directly on
overhead transparency film using a laser printer. There may even
be a product equivalent to carbon tissue that you can produce
directly using a laser printer.... Check the literature.
Mark Zenier
David Milne <dmi...@camtech.net.au> wrote:
>Has anyone here made silk screens for their own front/rear equipment panels?
>If so, how did you go about it?
>Or, do you know of a website that describes the processes involved?
Try a web search for Ulano. They seem to be the dominant supplier of
supplies.
One caveat: you need a fairly big work area that you don't mind getting
splattered with pigment.
Mark Zenier mze...@eskimo.com mze...@netcom.com Washington State resident
John Devereux
(Douglas W. Jones,201H MLH,3193350740,3193382879)
wrote:
>From article <391189F2...@camtech.net.au>,
>by David Milne <dmi...@camtech.net.au>:
>
>> Has anyone here made silk screens for their own front/rear equipment panels?
>> If so, how did you go about it?
>> Or, do you know of a website that describes the processes involved?
>
I wonder if you could more easily make a silk
screen using the "toner transfer" method that some
use for pcbs?
-- John Devereux
Douglas W. Jones,201H MLH,3193350740,3193382879
by John Devereux <jo...@devereux.demon.co.uk>:
>
> I wonder if you could more easily make a silk
> screen using the "toner transfer" method that some
> use for pcbs?
An intriguing idea. The short answer is no. The volume of the toner
must be sufficient to block the pores in the silkscreen fabric, and
the volume of toner in the original photocopy is so close to nil that
there just isn't enough available for transfer!
But! There is hope. Schemes like Press-N-Peel, where the toner adheres
to a secondary membrane, adding significant bulk, might just work.
The question is, how do you make the toner plus membrane adhere to the
screen. Thermal transfer won't work with typical synthetic polymer
fabrics, but I have heard of silkscreen printing from very fine stainless
steel fabric (at outrageous price, but with excellent dimensional
stability). Solvent bonding might work, assuming the solvent doesn't
dissolve your fabric.
Doug Jones
jo...@cs.uiowa.edu
Spehro Pefhany
> I wonder if you could more easily make a silk
> screen using the "toner transfer" method that some
> use for pcbs?
> -- John Devereux
You'd have to tread the fine line between melting the polymer toner and
not melting or distorting the screen fabric. Other than that, it might
work. You'd need negative right-reading in that case, of course you'd
try to put it on the bottom of the screen. You'd also need some method of
backing the screen up (a block of wood?) when doing the transfer.
Adam Seychell
John Devereux wrote:
>
> On 4 May 2000 20:02:42 GMT, jo...@cs.uiowa.edu
> (Douglas W. Jones,201H MLH,3193350740,3193382879)
> wrote:
>
>
> I wonder if you could more easily make a silk
> screen using the "toner transfer" method that some
> use for pcbs?
>
> -- John Devereux
>
I tried ironing toner directly onto aluminum panels for homemade
instrument cases. results are quite good. I found the aluminum needs to
be etched in 10% NaOH for few hours to get a good adhesion. Etching also
gives the aluminum a nice dull finish. You need to apply more heat
(longer time) than you do when making a PCB. A hot roll laminator may be
perfect for this.
John Devereux
Dale Gloer
been discussed.
I have not tried thisproduct but was wonderingif anyone had or if it would be
the answer for the original poster. It is a silk screen that you expose in
daylight and process in water. Here's the url:
Dale Gloer
"Douglas W. Jones,201H MLH,3193350740,3193382879" wrote:
> From article <iIMSOVply7R8FH...@4ax.com>,
> by John Devereux <jo...@devereux.demon.co.uk>:
> >
> > I wonder if you could more easily make a silk
> > screen using the "toner transfer" method that some
> > use for pcbs?
>