DIP Online
Designs Ink
Publishing Article Archive and Reference Library
Articles
by Chris A. Paschke, CPF GCF CMG
"TTPM - Time"
January 1995
Trends for
1995...hum, hard to believe it's time to think about that again. Last year I addressed both conservation and
lamination as growing trends to watch throughout the 90s, and I still see that
development. Conservation mounting
techniques are strong as ever and are most definitely here to stay!
So what's
happening on the non-conservation mounting front? Laminates will continue as a glazing
alternative, but this year the "hot" item to consider, if you haven't
gotten into it already, is canvas look-alikes.
Development of and increasing consumer interest in canvas transfers is
making it an actively viable and growing market. There's lots of profit potential in this
arena.
Manufacturers and
distributors are actively promoting laminating films, adhesives and canvas
texturing procedures that individual artists, framers and photographers are
able to use within their own facilities.
There are a variety of techniques and materials available to use
depending upon your comfort level of using wet glue, dry film and/or laminating
procedures.
There also remain
the numerous commercial transferring companies poised and ready to transpose
your customer's photo or print manually, chemically, or even through computer
imaging by mounting it onto canvas for you.
So there seems to be no excuse left not to jump onto the canvas
bandwagon!
MOUNTING
EXCELLENCE
In line with the
development and profit trends for 1995, we must never cease striving for good
mounting technique. This may often best
be achieved through a solid educational foundation in mounting procedures as
well as simply learning through repetition and mistakes. Of course learning by doing generally has a
learning curve of failures, and ultimately stands on the assumption your
results will eventually be perfect and predictable every time. Predictable and fearless mounting results
should be expected.
Since "time
is money", being efficient when it comes to your comfort level and
understanding of mounting techniques is imperative. Ironically, the fastest and most efficient
form of permanent mounting often creates the greatest degree of anxiety...dry
mounting! Somehow, the healthy respect
we are supposed to have when applying heat many items often turns to fear
instead. Do not be afraid of your dry
mount press, rather strive for a better working understanding of it, by
learning about the and truly understanding basic elements of mounting.
THE ELEMENTS OF
TTPM
Time, temperature,
pressure and moisture (TTPM) are the four basic mounting elements from which
all successful mountings will develop, and in opposition, reasons for any
unsuccessful mountings may be tracked.
All mounting may be individually analyzed by going back to the same four
basic elements.
The ratios of time
to temperature may vary greatly depending upon the media, mounting process,
equipment and adhesive being used. The
basics of wet, spray and pressure sensitive mountings follow many of the same
rules as for dry mounting, but often include the need to understand "open
time" (also called "tack time").
This is the workable time (TTPM) required by the adhesive, prior to
positioning the print to be mounted, as the solvent evaporates, in preparation
to make the bond.
Open times vary
depending upon individual products, so be familiar with manufacturer's
suggested usage of the products you select.
Application time
(the time it actually takes you to apply the adhesive) also comes into play
with wet and spray adhesives (TTPM). A
good uniform coat of adhesive must be applied in order to guarantee good
adhesion. Too much adhesive unevenly
applied may cause bleed through, while any areas which have begun to dry prior
to mounting the art will not create a lasting bond (TTPM). Although a basic bond will be created within
the first hour, more permanent bonding will take 4-24 hours and should be
placed in an undisturbed area under pressure (TTPM) during that initial set-up
time.
DRY MOUNTING TIME
The time it takes
to dry mount a project will vary depending upon the adhesive, substrate, size,
temperature and item being mounted. Now
if that isn't enough to confuse you...there's more. Most tissues and films mount between
165F-190F. The "dwell time" is
the time a project must remain in the press to adequately heat all inert
materials, squeeze out the air, activate the adhesive and create the bond. The total size of the project and thickness
of substrate or mounting board has a direct effect on this dwell time.
If a project is
removed too soon for proper bonding to be achieved, it may be put back into the
press for a second time. If however the
mounting was only left in the press for 2 minutes when it actually needed 2-1/2
minutes to mount, it must be placed back into the press for the initial 2
minutes of mounting time plus 1/2 minute in order to achieve that desired
additional 1/2 minute of dwell time.
Once again...the
mounting must remain in the press a total of 2-1/2 minutes the second time, in
addition to the incomplete 2 minute mounting the first time, for a total press
time of 4-1/2 minutes. All of the mounting
materials from the release paper to the substrate must be reheated to the
previous mounting temperature (TTPM) once again and then the extra time added
on.
If rushing a dry
mounting requires it to be remounted, the entire concept of time efficiency
affiliated with the dry mounting has not been met, for the single item has thus
been mounted twice. Remember, "time
is money" and this is not time and cost effective. Do not rush projects only to begin again.
Time is ultimately
a variable that you will control manually based upon other selected mounting
materials.
At the
manufacturer's recommended temperatures, the proper time to leave a project in
your press is long enough to mount it correctly the first time!
It's important to
match the proper time/temperature ratios.
Since it has been increasingly desirable to dry mount at lower
temperatures (TTPM), the dwell times must be increased. Simply because a particular print may easily
tolerate a higher temperature does not suggest turning up the temperature to
cut down the time required to mount.
This can be a risky endeavor and quite often you will be the one to
lose. It is far better to mount at a
lower temperature for a longer time than to increase the temperature in an
attempt to speed up the production process.
It only takes a few remountings to blow the entire "higher
temperature/shorter time" theory
out of the water.
MECHANICAL PRESSES
An average
mounting time for dry mounting will vary slightly between mechanical and vacuum
presses, as a direct result of their physical construction. Dwell times will vary depending upon the
overall size and thickness of the substrate selected, with an average mounting
time in a mechanical press running from 1 minute for and 8x10" mounting to
3 minutes for a 20x24" mounting, or approximately 1-3 minutes.
Pre-drying (TTPM)
is required as a manual step prior to mounting when using a mechanical press
which will increase the physical time required for the total mounting. Though generally never more than 10-15
seconds per item, it could add a minute or so to the total mounting
process. This will be discussed at
length in "TTPM Part Four: Moisture".
HEAT VACUUM
PRESSES
When using a heat
vacuum press, total "cycle time" for an average mounting will be
about 4 minutes up to 32x40" while 5 minutes is more common up to
40x60", or approximately 4-5 minutes.
The total cycle time includes "draw time" for the press to
pull it's vacuum plus the actual dwell time required to heat up all the
materials to the required bonding temperature.
Since predrying (TTPM) is not a required step in vacuum mounting, a
16x20" print will mount in most vacuum presses in about 4 minutes.
HOW LONG IS LONG
ENOUGH?
The important
point to remember concerning the mounting element of TIME is to establish a
comfortable working time/temperature ratio, based on your average substrate
size, thickness and adhesive selection.
Average mounting
times, when temperatures are properly set, for a mechanical press run from 1-3
minutes with an additional minute for drying and 3-5 minutes for a vacuum
press. Now, I suppose I could have
simply said that at the beginning, but then again the issue is time and how
long is long enough?
Next month I'll
explore taking your press' temperature more seriously in part two of
"TTPM".
END
For more articles
on design or mounting search your desired topic under Articles by Subject.
If you know your specific title check Articles by Title.
Additional
information on mounting basics is found in
The Mounting
and Laminating Handbook, Second Edition, 2002, and
The Mounting
And Laminating Handbook, Third Edition, 2008.
Creative
Mounting, Wrapping, And Laminating, 2000
will teach you
everything you need to know about getting the most from your dry mount
equipment
and materials as
an innovative frame designer. All books are available from Designs Ink
Publishing through this website.
Chris A Paschke,
CPF GCF
Designs Ink
Designs Ink
Publishing
785 Tucker Road,
Suite G-183
Tehachapi,
CA 93561
661.821.2188
info@designsinkart.com