Here we go again, more about those issues of TIME, TEMPERATURE, PRESSURE and MOISTURE, and this time I really want you to take your temperature seriously. "Predictability" should be the hallmark of dry mounting. When repeatedly mounting similar items, the end product should always turn out the same each time. Generally speaking, if there is inconsistency with your dry mounting it may usually be tracked to one of the key elements being out of sync with the others, proper ratios and control are imperative.
The ratios of time, temperature, pressure and moisture may vary greatly depending upon the media, mounting process, equipment and adhesive being used. Since suggested mounting temperatures for assorted dry mount adhesives and films range everywhere from 150ºF to 225ºF, it is impossible to give the end all, ideal temperature to be used in every situation. The best to be done is explain and establish a median or average (safe) daily temperature that will meet most of the normal mounting project requirements.
Maintaining Control
By establishing an average base temperature to be used for as much mounting as possible, you will eliminate wasting any potentially productive mounting time by having to wait for the press to heat up or cool down. I do a great deal of both creative and straight-forward mounting, and I leave my press set at 180ºF for daily routine projects. Seal Products suggests the mechanical press be set at 10 degrees cooler than a hot vacuum press, but this is not a mandatory practice and I generally set both presses at the same 180ºF. If a number of individuals are regularly using all of the equipment, it may be most sensible to maintain control by using the same temperature on your mechanical and vacuum presses.
In a mechanical press, at 180ºF an 8x10 requires about 1 minute, while an 18x24 requires 3 minutes (plus about 1 minute for the predrying process in both). In a vacuum press, the same 180ºF will mount either piece the (8x10 or 18x24) in about 4 minutes. The common question of "If it takes 4 minutes at 180ºF can't I mount the same item for 2 minutes at 200ºF, thus allowing me to mount twice as many pieces in the same amount of time?", is a good question. Perhaps in theory this appears correct, but take into consideration having to more closely monitor each project to avoid damage, now, you end up wasting time. And, what if the one project damaged because of excess heat applied too long is non-replaceable...problems! An extremely good rule to follow is "it's better to be slow and safe, than fast and foolhardy".
Damage, in some cases might also be defined as simply altering your "desired end product". You must maintain the control and predictability mentioned earlier! Individual tissues and pure adhesive films may vary, depending upon the item being mounted, it's thickness or delicacy, it's substrate and your desired end product. Consider a 16x20" piece of delicate rice paper with dominant visible fibers is to be mounted onto a dark mat board encouraging a color bleed tint for use as a designer mat. By using pure adhesive film (Fusion 4000 or TM3) to guarantee the accented rice fibers in the paper to remain visible and enhanced by the tint of the board, it must either be mounted at the adhesive's minimum temperature of 170ºF for 2 minutes or at the manufacturer's recommended temperature of 190ºF for as long as 15-30 minutes. The longer (time) the rice paper remains under pressure, in the chosen temperature, the more it will absorb this particular adhesive and thus become more transparent (see "Ghosting Newsprint", PFM November 1991).
Variables
Since posters or paper graphics (non-limited editions) often make up a major portion of daily mountings, using rolled tissue (ie: MT-5, ColorMount, or TM2) in a press set at 180ºF would be a reasonable selection. Vary the time not necessarily the temperature to accommodate substrate and size. As mentioned in Jan/Feb "Adhesive Trends" the most recent development in heat mounting is a basic lowering of all tissues to less than 200ºF recommended mounting temperature. As long as you maintain that understanding, the variables will occur as more delicate or extreme heat is required. You generally will choose to dry mount vellum (once tested), tissue, silk, even Ilfochrome Classics at the lower 160ºF using compatible tissues (i.e.: ArchivalMount, TM4 or Drychival) if an alternative mounting method (which may be preferred) has not been selected. Multiple 4-ply rag boards with layers of art paper and adhesive between for pin striped bevel designs may require more aggressive techniques and adhesives (ie: Fusion 4000 Plus, TM3 or Flobond), longer dwell times and higher temperatures. Remember the entire mounting package must reach the required temperature, and denser substrate or multiple layering will always take longer.
Photographs require some care, and extremes of temperature for long durations should be avoided, but you need not be afraid of the mounting process. Again, watch the time factor! Leave them in long enough to liquefy the adhesive and mount, but be certain to always use a breathable tissue (i.e.: ColorMount or TM2) never a glassine core (i.e.: MT-5 or TM1). Setting the press to accommodate laminating films (even for use with photos) clearly illustrates a photograph's tolerance for heat when you consider the 210-225ºF temperature requirements. Thus, fear not the 180ºF for mounting...just don't forget it overnight!
Conclusion
All manufacturers offer time/temperature requirements, tables and general mounting information concerning each of their individual adhesives and films in relation to substrate size and density. You need to be aware of the manufacturers' minimum and suggested mounting temperatures...and then apply the facts to your individual needs. It is often best to establish a good average use temperature of about 180ºF, which should meet most of your mounting needs. Don't regularly attempt to vary the press temperatures, it is a source of frustration you shouldn't have to deal with. Mounting should become extremely instinctive if you wish it to be truly profitable.
Duplicating a particular look must be achievable without reinventing the wheel each time, always note the time/temperature on the back of your "created" mat corner samples. Creating a solid, comfortable routine, involving familiar adhesives, quality substrates, repetitive times settings and common temperatures, ensures predictable and successful mountings without burning up excess brain cells. Save "the burn" for the special projects you are charging more for!
END
Copyright © 1992 Chris A Paschke
For more articles on mounting basics look under the mounting section in Articles by Subject.
Additional information on all types of mounting is found in:
The Mounting and Laminating Handbook, Second Edition, 2002,
The Mounting And Laminating Handbook, Third Edition, 2008 and
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
P 661-821-2188
chris@designsinkart.com