HOW MUCH PRESSURE IS ENOUGH?
By Steve Conde
I just saw a video (not on CondéTV by the way) that inadvertently raised the old issue of “How Much Pressure Is Enough?” and then confused the issue completely with just one piece of inaccurate information.
I have no desire to beat this guy up over a slip of the tongue but it is very important that sublimators understand pressure, so here’s a short tutorial:
FINAL ANSWER: The winning answer to how much pressure is enough is (drum roll please): As much as it takes to cause the transfer to come into full and complete contact with the substrate so there are no air bubbles remaining.
Through the years, we have given this many labels: “LIGHT, MEDIUM or HEAVY” remain the best descriptions but those are confusing since everyone is different. A petite girl might have a very different sense of “Heavy” than a 300# man. So, we have tried to do it by the number of hands it takes to close the press: “Two Fingers for Light, Two Hands for Medium and extra effort for Heavy. But that doesn’t really help much either since everyone is different.
George Knight tried to fix this with a “Pressure Gauge” a number of years ago. The “gauge” readout on the machine shows up as a number (0-9). Although this has helped in consistency between people of different sizes, it only adds another number to the mix. Is light pressure a 1 or 2 or 3? The secret is always with the operator, not a dial. You must learn to “feel” the difference.
To further confuse matters, there is the old “Rule of Thumb” that says, 20psi is light pressure, 40psi is medium and 60-80psi is heavy pressure. Unless you own a hydraulic press however, this is all wrong. No desktop press could withstand 20psi across the platen. It would be like parking a Lincoln Town Car on top of the press. Those numbers, although they may be accurate for someone with a hydraulic press, mean nothing to the manual press user. They refer to how much air press is allowed into the air piston and is not the amount of pressure exerted in the press.
So what is the right answer? I have already told you: As much pressure as it takes to remove any air between the transfer and the substrate without damaging the substrate. For most people, if it takes both hands to close your press, that’s probably enough. Excessive pressure isn’t necessary. For the slight of build, this may mean a good “Umph” to close the press. For an adult man, it will require some effort to close the press but no strain.
What IS important is that you always hear the press “latch” when it closes. The amount of pressure you apply from the time you first feel resistance to the time you hear the latch equals the amount of pressure actually being applied.