silkscreen printing

[burraboy]

I've done a bit of this over the years, certainly not commercially, but T-shirts for special occasions and the family and so on. I'm now looking at etching artwork into metal (brass & aluminium) and wondering about screening the design onto the surface so the ink acts as the resist while the etching takes place. My experience with inks is only the fabric kind, so could anyone comment on the availability of an inks and solvents that would stick to metal and remain waterproof for the process. I would probably remove it mechanically by polishing or with a solvent after the etching has finished.

[Pusser]

You can get photo resist at jaycar. You use it to make circuit boards - paint it on the copper, put a mask on, expose it to UV light then use an acid to etch the copper (away in the case of a circuit board. You can also get resist pens which do similar things. Don't know it this meets your needs though.

[burraboy]

I have used a PCB pen in the past as the resist when drawing some basic designs in the etching process, but the designs I would like to use are more detailed and not suitable for hand reproduction, thus the possibility of using a screen to reproduce it. Does the resist for the PCB's (not the pen) lend itself for use by printing with a screen do you reckon? Or perhaps there is a dedicated ink that would do?

[burraboy]

Just thinking about the photosensitive paint. Do you think I could use a transparency of the design to achieve the same result without using a screen? How fine a line would it allow me to achieve? Say the sort of definition to reproduce written words like the ones on this page?

[Pusser]

What I know about screen printing could be printed on a postage stamp and have space for an executive summary. But you will see from the examples here that quite fine lines can be achieved.

http://www.bcae1.com/circuitboardetch.htm
http://www.robotroom.com/PCB.html
http://www.atmsite.org/contrib/Webb/pcb/
http://hackedgadgets.com/2006/06/24/photo-etch-circuit-board-process/3
http://themodelmakersresource.co.uk/articles/article001.html

And if you want to try sandblasting the design
http://photobrasive.com/photo_resist_film.php

Note photo resist is abailable as an ink or a film but some of these methods just use a leser printer and transparency film (You iron the tranparency and transfer the toner to the metal. )

Hope that gives you some idea and is helpful.

[Arch Stanton]

I've done a bit of this over the years, certainly not commercially, but T-shirts for special occasions and the family and so on. I'm now looking at etching artwork into metal (brass & aluminium) and wondering about screening the design onto the surface so the ink acts as the resist while the etching takes place. My experience with inks is only the fabric kind, so could anyone comment on the availability of an inks and solvents that would stick to metal and remain waterproof for the process. I would probably remove it mechanically by polishing or with a solvent after the etching has finished.

G'day Burra,

I was a screen printer for 20 years but I never had to do anything like you want to do however I'll throw in my 2 bobs worth.

There are inks used which are printed on metals for making Printed circuit boards but I don't know what they are but if I wanted to print on brass and aluminium and later wash it off then I would use a lacquer ink.

I've been out of the industry for 10 years and am not up to speed on all the suppliers so I can't be any more help, sorry.

What I would suggest is that you ring the ink suppliers and ask them. They should be in the yellow pages under "Screen Printing Supplies".

[burraboy]

Thanks Arch,
that ink for pcb's could be what I'm after. If you don't mind, could you elaborate a bit on 'laquer' inks, I've only done fabric printing with acrylic inks.

[billbeee]

Burraboy,
I have done a fair bit of of art silkscreen prints, and I have also done some etching.
To me using a silk screen, which is one multiple printing process, to get an image onto an etching plate, which is another multiple process seems a bit strange. Newspapers are printed from thin zinc pates that have photo resists on them.

There are heaps of photosensitive emulsions that you should be able to use on an aluminium or copper plate. You probably will need a half tone screen to get the dot patterns if you are looking for photo realistic images.

Even silkscreen emulsion might work directly on you plates. I guess it depends on what process you are using. I used to print some of my positives off on my computer, ordinary plain paper, not clear film as it should be. I'd squeegee it to my screen with vegy oil and that made it transparent enough to expose the emulsion.

I can remember using things called solar plates for making etchings. They already had the emulsion on them.

Look up etching on the web, forget screen printing. People have been etching metal for centuries before screen prints came out.

What are you intending to make, your end result?

Cheers
Bill.

[burraboy]

Thanks for the input Bill, the end result will be small plates etched with a celtic knotwork design and some basic lettering that I will attach to some articles that I make. The problem lies in getting the design onto the metal in a resist medium for the etching process. I tried unsuccessfully with some special blue paper from the US that I printed with a photocopier and then applied to the metal using heat. Incomplete transfer was the problem there.
I thought I may be able to use screenprinting to produce the design but was not sure about what sort of ink would do the job. My investigations have shown me that there is an ink which is refered to as being like 'bitumenised roof paint' which may do the job with an appropriate mesh. I have seen medieval type bookmarks in brass made this way and the results seem good. Next problem is making up a photo stencil of the design.
Another alternative that has ben suggested here is to paint the metal pieces direct with a photosensitive emulsion and expose them with a OHP sheet with the design on them. This in some ways may be the easiest method, but in the long term, probably the slowest too.
I'm still looking into what will suit my situation the best. I'm leaning to the screenprinting option but don't have experience with making up photo screens. It may be that I will have to learn about this whichever way I go. Any input is most welcome!

[echnidna]

a non water soluble ink is all you need.
After etching you need to remove it with its own solvent

[billbeee]

Hi Burraboy,
Bob's right, I guess any oil based ink should do, just do a few tests.
The thing to look for something that does the job, but is still easy to clean off your screen and your plate after.

Your mention of bitumen based ink, reminds me that we used to use something like Pabco Hydroseal or similar.
We used it straight out of the can, rolled it out on a sheet of glass with a rubber roller and then rolled it onto the plate in a thin layer. Next day it was dry enough to draw on with a point, and then etch.
You would have to play about with the consistency a bit for making a screen ink, a touch of turps in it maybe.

After etching I'd wash the resist off easy with turps, (outdoors under a tree) but the "new age rs" non-toxic printmakers used to feel smug using vegy oil indoors. Naturally they took twice as long to clean up.

Main thing with all resists is to get your plate scrupulously clean. We polished them with whiting powder for ages, a right pain in the bum.

If you are only doing line art (no halftones) then your photo stencil negative is easy.
Prepare it on your computer in a graphics package, and then take it on disk to a copy bureau and get them to print it out with a laser printer onto clear film.
Even if you want tones, most graphics package will give you a dithering option. That's what I used for some of my paper negatives.

To give you an idea I'll take some photos of some my prints and post them later in the "art" category.

[billbeee]

Hi again,
I was going to start another thread but don't want to be accused of hi-jacking.

Below are four of my efforts.

The dog is a straight etching, Pabco Hydroseal resist on a zinc plate. That is the drawing is done direct with a stylus (steel scriber) onto the black resist. Line only, the shading is caused by leaving more ink on the plate in the darker parts.

The old guy is an etching first and then aquatint added to give tonal values. Drawing with the stylus makes light marks on a dark surface. These light marks are the zinc plate showing through. When the plate is etched in acid these marks then become grooves which hold the ink for the final print.

So in effect when drawing on the plate directly you have to draw in negative, your lights become dark in the print and you shadows become light.
Tricky eh! Too tricky for me on the old guys left hand cheek. At some stage my mind switched over and I started drawing normally so the ravaged look wasn't intended but an accident. I always intended following this up and making positive and negative aspects in the one print but never got around to it.

The two screen prints are both done with two different types of negatives. Paper print out from my computer from a modified (corel draw) photograph for the frog and the boy, and all the hand worked stuff was done painting by hand of clear plastic to make the negative.

I made almost all of my screenprinting gear myself, vacuum frame powered by my Makita shop vac. RHS steel screens. I made a light box with about 10 fluro tube in it, for exposing the screens, but it was too slow so did it in sunlight.
I even finished up making my own inks from wallpaper paste and painter's tinters.

The things you do when you you should be making a dollar at your day job.

Cheers
Bill

[burraboy]

Finally, some finished product!
http://i278.photobucket.com/albums/kk103/synwhistles/etchedlabels.jpg

I got a photographic screen made up with a coarse fabric (80T) and printed the design with bitumen roof paint to act as the resist for etching. After etching the resist comes off easily with turps.
These little labels aren't exactly art, but I can see there are possibilities in the technique, especially with multiple screens and several etchings to get some nice results

[billbeee]

Hi Burra, I thought this thread was faamiliar.
Great to see that you persevered with it. Good results too. From now on it gets easier, spend more time on new designs and less on technical matters.
Cheers
Bill

[tea lady]

Oh! Very interesting. Might revive another project I;ve been thinking about. Thanks guys.:2tsup: