Designs Ink Publishing Article Archive and Reference Library
Articles by Chris A. Paschke, CPF GCF CMG
"TTPM - Time"
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!
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.
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".
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 Publishing
785 Tucker Road, Suite G-183
Tehachapi, CA 93561