How to convert 3M - UV exposure unit
- Harold Kyle wrote:
> All this to say that if you care about the quality of your (expensive)The UV lights in my 3M UV exposure unit are "Philips TLD 15W05". Are these
> photopolymer plates, you should not use an exposure unit for alt-process.
> You need a vacuum and you should try to use kreene, which will minimize
> light distortion. I sell the kreene at $1 per square foot. Kreene needs to
> be replaced periodically because it loses its plasticity and can soil up.
> Oh, and I also have a few extra vacuum pumps laying around
correct UV lights for letterpress photopolymers (somebody told me the
frequency could be wrong)?
If I would convert the unit I can take out the existing glass plate very
easy and then would have to go for the kreene & vacuum stuff. What distance
would you typically have between UV-lights and the kreene?
(For new listmembers you can see the unit at http://groups.yahoo.com/ (with
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>An lighting and electrical store with be more authoritative than me, but
>The UV lights in my 3M UV exposure unit are "Philips TLD 15W05". Are these
>correct UV lights for letterpress photopolymers (somebody told me the
>frequency could be wrong)?
I use Philips TL series lamps in my platemaker. Mine are TLK and a
different wattage. TLDs will most likely work for you.
>If I would convert the unit I can take out the existing glass plate veryThe platemakers I have seen have had 1.5 to 2 inches distance between
>easy and then would have to go for the kreene & vacuum stuff. What distance
>would you typically have between UV-lights and the kreene?
the lights and the plate. Too close, and the shoulders of reverse type
etc. will fill in; too far and the shoulder will be too vertical and
weak. No one has ever really confirmed this belief of mine, though. Have
people had luck with other distances?
Your conversion is more of an overhaul. You'd have to add quite a bit of
hardware to make it work with kreene and a vacuum. As long as we're
converting platemakers for polymer, you might find it easier to convert
an old offset platemaker by replacing its light source with the fixtures
in your contact frame & kreene. Just a thought.
~ ~ ~ ~ ~ ~
Fine Printing and Binding ~ Digital Letterpress Supplies
640 Fellows Avenue ~ Syracuse, NY 13210
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- Dear Harold
This is exactly what happens during photopolymerization. With longer
exposure times the photopolymer begins to fill in (just the opposite
of what you would common-sensical presume). Reverses and solids
require less exposure, thus are given more vertical strength.
But what is interesting here (in your statement) is the possibility,
with one of these units, of being able to mechanically modify exposure
rates independent of exposure time!!!
> The platemakers I have seen have had 1.5 to 2 inches distance between
> the lights and the plate. Too close, and the shoulders of reverse type
> etc. will fill in; too far and the shoulder will be too vertical and
> weak. No one has ever really confirmed this belief of mine, though. Have
> people had luck with other distances?
- Just to backtrack a bit:
I'm attracted by rumors of machines available cheaply. Could someone
tell me what a generic name or description might be for a "convertable"
UV exposure unit? I'm looking for some names (or model types) or terms
I could use to describe what I am looking for when calling a used
equipment dealer or perusing ads. I am familiar with the units made
specifically for photopolymer, but not with the other machines used by
the other printing industries.