I started with an ambitious project - I wanted to screen print from home. Not an A4 screen print, but a huge XXXm screen print. I'm not exactly sure why I have the need to do this, but I wanted to set myself the challenge of doing it.
My background is art and design, and I did but the briefest bit of printing on my foundation course many years ago - and that was metal plate printing, not even screen printing. About six or so years ago I did a course at Weymouth College - evening course without any qualification - lasted some seven or so weeks, one evening a week as I remember. I really got the bug for it, and ever since I have had the burning ambition to do it for myself.
This is an image I made of StGeorge, the first screen I ever printed. The thing I love is that you can make the colours by hand. Yes, you can do halftone and print photographs but I just love massive scale and intense colours that you make by eye.
Fast forward to a year or so ago. I bid on a screen printing table hoping for the best. I lost out, then lost out on another one. The next one I bid on, I didn’t get, and I wrote to the owner asking if they might put me on the list - oh yeah thats going to happen. But it did! and lo - the first buyer got it home and couldn’t house it because its an industrial scale one. The owner phoned me back and asked if I wanted it still. And the rest is history.
As you can see from the scale, its XXXL. The mounting bars accommodate easily A0. In addition it has a physical squeegee winding mechanism plus the mother of all vacuums on the underside with foot pedal - this thing was designed for churning out hundreds of prints.
But there are a few problems. Hence this is pt1 of this posting. Firstly physical - I have space to accommodate it in my newly built cabin - but its designed to be put up on legs, and thats not convenient. I'm reasonably able to manhandle it - but best idea I thought is to have it mounted to drop from the vertical. To that end I have to have legs constructed with a pivot. And given its weight - Im guessing 300kg I will need to reinforce the cabin wall to make sure it doesn’t rip itself from the hinges when it lowered. Ok so more about that in a later post.
The general principal.
- Make your artwork which then has to be either spot colour or halftone in CMYK.
- Create a transparency for said artwork - could be massive
- Paint light sensitive emulsion on the screen and expose the transparencies in whatever order.
- Finally - mix your colours and print.
- Construct giant frame for hanging the work.
So - step 2, Im not going to do. Its a one time process thats either correct or incorrect. Im not quite sure yet exactly how its going to work, but speaking to a local printers they will make things called a milky that they use for exposing plates.
Step 3 is the main concern of this post. Ive got to build an exposure unit.
Traditional units use UV tubes - not very powerful so the screen has to be placed almost on the lights. In addition the people selling them know there is a lack of practical knowledge to build a unit so they often try and sell for like £600 or so - not in my budget for a gigantic unit that you use the few times. Don’t have space. There were all kinds of exotic stand unit ideas with grow lights and mercury lights that get absolutely red hot - and Im in a wooden cabin so I nixed those ideas.
So I came up with a UV LED having seen this very helpful youtube clip.
So I assembled the follwing items,
They are in order,
- conductive paste for gluing the heatsink to the chip
- A massive heat sink - its comically large
- A small stepdown trans for 30v to 1.5 or something - its got a digital pot on it so you can set the voltage
- A 30v 200W trans
- A gigantic 200W UV chip
All I have to do now is to link them altogether and fire it up. The chip has no +- marking, great. So its all a bit of an experiment. the chip wasn’t cheap - £60 I think.
