Designs Ink Publishing Article Archive and Research Library
Chris A. Paschke, CPF GCF
"Heat Systems: Mechanical vs. Vacuum"
I am often asked "which is better...a mechanical or a vacuum press"? Quite simply they both have benefits and drawbacks depending upon your intended usage. In this month's article I will be discussing the differences between mechanical and heat vacuum systems, I will not however be discussing the differences between specific manufacturer's presses. Targeting your market and thus determining your growth goals will often get you to thinking on a larger scale and that is good. By thinking larger than you actually need at this point in time often allows for continued business growth without mounting limitations.
The issue of "space" often appears to be the first point of consideration for shops selecting a new press. I have previously addressed setting up the "ideal" work station for dry mounting in PFM's July 1992 store design issue, and at first glance, mechanical presses appear to be much more compact and therefore more likely to be easily "puzzled into" a tightly packed frame shop. Although it is true the overall outside dimensions of a mechanical press is smaller and will therefore fit easier into that unused corner of your workroom, one of the dynamite benefits of this press actually requires plenty of additional space surrounding it for accessibility and movement.
Unlike a vacuum press which is limited to mounting items which fit inside it's frame, a small mechanical press can actually mount items near twice it's width and miles longer then itself using the "multiple bite" process. This process is only limited by the walls, cabinets and equipment remaining in close proximity to it. Because of it's compact nature, small mechanical presses can be relocated on the rare occasion an oversized item is to be mounted...say to the center of your workroom, the hallway or even the floor, but then you need to consider dirt, dust and the inconvenience of working in an uncomfortable setting. On the other hand, any vacuum press may be fitted into the corner of a room since the mountings are always limited to what actually fits within the closed unit. Remember, whether mounting a 40x60" project in a large vacuum or as a multiple bite project in a mechanical, the same space will be required to accommodate the full 40x60" sheet.
A major space advantage often not initially recognized when considering the space required to fit a large vacuum press into your shop is the new found workspace on the top of the flat vacuum press. When I originally began attempting to rearrange my facility to accommodate the new press, I had to eliminate some shelf and storage space, but it wasn't until I installed the new 40x60" unit that I actually realized the additional storage space on the two shelves created below the press as well as the additional table top work area I had never considered.
The smaller mechanical presses were originally developed for artists and photographers since they are single bite limited to approximately a 16x20" mounting. Custom framers would be encouraged to graduate up to the larger version if dominantly mounting items no larger than 24x32". The multiple bite flexibility of a mechanical press is an advantage to the framer who only rarely requires the facilities to mount an oversized poster, say a Michael Jordan or an occasional 24x36".
This same press, however, would be considered a time detriment to a framer who routinely mounts numerous 24x36" posters or uses 32x40" substrate which would require the "two bite" method with the larger (or four with the smaller) mechanical press. If routine 32x40" boards are to be used then perhaps a smaller hot vacuum with a maximum mounting of 32x40" might be the best consideration. Likewise for a framer who stocks or routinely expects to mount 40x60" prints needs to look into the larger vacuum. Though vacuum presses are available as small as 16x20" they too were originally designed for the photographic market and are generally considered rather small for most regular framing operations.
Another advantage of the vacuum units is the flexibility of using only the vacuum, thus allowing the benefits of heat mounting, laminating and cold mounting, when heat is not advisable. I'm not attempting to state ONLY consider a heat vacuum unit, for there will always be the place for all sizes of cold vacuum frames too, it's simply that there are limitations when heat is not available (see "Vacuum Mounting", PFM May 1992). Vacuum systems also allow for increased flexibility in multiple mountings, mounting and laminating all in one step, and as mentioned above use of both heat and cold vacuum adhesives.
The basic elements of time, temperature, pressure and moisture come into play when considering the differences between mechanical and vacuum presses too, as defined by the very names of the presses themselves. When using a "mechanical" press it is your responsibility to make certain the pressure of the press is properly adjusted to the substrate you are using for each specific mounting. If the pressure is too light bubbles might appear, if too tight dents could be formed in a foam substrate during a multiple bite process. It is also required to pre-dry all mounting materials prior to the mounting process to remove any excess moisture. Both of these steps may be eliminated when using a "vacuum" press. The physical drawing of the vacuum pulls the moisture from the materials automatically, while the rubber diaphragm or bladder naturally conforms to the thickness of each individual substrate thus adjusting for pressure. The actual pressure of a mechanical press is about 2-4psi whereas a hot/cold combination vacuum press is approximately 12-14psi (24-28"Hg). This lower poundage in no way inhibits the ability of a mechanical press to produce as good a mounting as a vacuum press.
There is also a type of mechanical press used more widely outside the United States known as a "hardbed" mechanical press (mechanical presses as compared in this article are known as "softbed" mechanical presses when discussed in that circle), which is capable of even higher pressure than a vacuum press.
Since routine maintenance of release papers, overlay foams and platens is necessary for either mechanical or vacuum systems, the other general maintenance considerations only surround the pumps of various vacuum presses. Included are recommendations to run some units 5 minutes prior to shut down each day to clean the vacuum system of accumulated moisture, regularly check the pump for moisture build-up, clean the filters and oil the pumps as needed. All manufacturer's manuals should be closely read prior to initial operation. Again, since no pumps are used with
mechanical systems none of this maintenance is required.
Electrical differences involve a standard 110 volt wall plug for a mechanical system while a 220 volt, three or four-wire system is required for vacuum presses. Most commercial buildings are set up to easily accommodate this extra electrical requirement, though a qualified electrician should be contacted to properly hook up the line.
All of this boils down to a few simple basic differences...
* Mounts and laminates
* Capable of oversized multiple bite mounting
* Takes up less physical table top space
* Uses 110 volt
* Lower capital investment cost
* Single mounts only up to 24x32"
* Must be manually adjusted for pressure
* Requires pre-drying of all mounting materials
* Top may not be also used as a work space
* Requires same surrounding area as substrate size
HOT/COLD VACUUM PRESSES
* Automatically adjusts to substrate thickness
* Automatically pulls moisture from materials
* Multiple mounting capabilities saves time and $
* Heat mounts, cold mounts, laminates
* Most mounting adhesives may be used (including wet)
* Maximum mounting limited to press frame size
* No oversized multiple bite capabilities
* Monitoring of vacuum pump, filter, oil levels on some models
* Requires 220 volt, three or four-wire hook-up and electrician
* Higher electrical usage
So what do I need to do to choose the right system for me? By asking yourself a series of questions concerning your current daily mounting materials, procedures, inventory and prospectus for future growth you can indeed select the most efficient piece or type of equipment to suit your specific needs and goals.
Considering the following types of questions will help direct you into whether you are ready for the capital investment of a heat system at all.
Am I doing a lot of wet or spray mounting?
Do I currently subcontract mounting to another framer?
Do I turn away mounting or laminating jobs?
Do I have heat mounting competition in my immediate area?
Is there additional marketing potential by mounting as a subcontractor for other framers?
Is there a market for additional mounting growth? laminating growth?
Are there potential engineers, architects, govt. offices in the vicinity?
This brings me to the most specific way of pinpointing the issue of press size, and in turn more specifically the type of press best suited to you. Although the resale value of heat mounting equipment remains high and the fact that mechanical presses seem to be work horses and in some cases the dinosaurs in the frame shop industry, it's generally best to purchase something a little larger than exactly what you require at this time, for you must always consider the growth potential and your marketing goals.
Now ask yourself...
How much 24x36", 32x40", 40x60" or 4'x8' foam board do I buy a month?
Do I currently sell poster art or limited editions?
Do I plan to increase my poster market?
How many oversized pieces do I currently mount? or hope to?
Do I plan on increasing inventory of larger pieces?
Do I sell, develop or promote photographs?
What is an average photo size?
How many large photos do I mount? or hope to?
Remember the total profit picture and payoff potential will include a complete service program including mounting, laminating and creative mounting applications (ie: "Tiered Matting"...PFM 1993), also keep in mind that without heat, laminating and many other creative applications may not be achievable at all.
The final decision is always up to you, but do ask for help in making your equipment selections. Though you may lust after the largest combination vacuum press available it may not truly suit your needs the best. If, however, that is the best selection for you and you really can't come up with the capital for the investment, then my advice is to save your pennies until you can afford the right one rather than buying smaller.
copyright © 1993, 2013 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 and creative applications in:
The Mounting and Laminating Handbook, Second Edition, 2002,
The Mounting And Laminating Handbook, Third Edition, 2008,
Creative Mounting, Wrapping and Laminating, 1999.
Chris Paschke, CPF GCF
Tehachapi, CA 93561