I would like to put here my 2 cents again, if you guys don’t mind.
I think things are becoming confusing because we have adopted a too much abstract point of view. If we are speaking about physics phenomena, we have to start by what we can observe. Let’s suppose an average penis is 6” length (NBP) x 5” girth. If we clamp so tight that 3” inch of the penis is practically “void”, we are raising the pressure at roughly double of when starting. So, if pressure in erect penis is 3 HG, clamping up to half length raise the pressure to about 6 HG.
First point: could we agree that this kind of work (remembering that clamps are so tights that volume under them is near zero) will easily cause a serious injury to the tunica albuginea? I suppose “Yes”. We could have a tears of tunica compressed by clamps, but also a break of tunica in the unclamped area, and damages in the glans as well.
Let’s see what happens with a pump: raising pressure to 6 HG will lead to same injury? Do a try, you’ll find the answer is “Not”.
So: analogous levels of pressure aren’t affecting in the same way the tunica when pumping as it happens when clamping. This is a fact.
Is theoretically possible raising pressure in the pump so much that same degree of stress on the tunica is obtained? Theoretically, yes. But let’s see what happens with lower numbers.
A clamp (so tight that volume under of the penis gripped is zero) wide 1 inch should cause a raise in the pressure inside tunica of roughly 1/6 higher. A practical experiment will tell us that 1) the expansion obtained is near (or above) dangerous levels; 2) the penis is rock-hard.
Translating that pressure to pumping, it would be a 3.5 Hg; this is a level of pressure not dangerous at all. This confirm what we have observed above.
What would be a level of pressure so high that tears or break of tunica would happen by pumping? I don’t think that even at 12 HG of pressure this could happens – let’s relate to what ttt just said about his experiment with pump. But what would happens (for most of us) using a 12 HG pressure when pumping? Easily, “fluff” penis, temporary ED, loss of sensitivity etc..
So: using a pump, the pressure is deforming other penile tissue’s than tunica more than it happens by clamping. It means: pressure is affecting (and deforming) tunica more when clamping than when pumping. It means again that, for our goals, pressure is more profitably used when clamping than when pumping. In the first case, tunica resistance is the limit; in the second, not.
The explanation of this fact could be that others tissue than tunica (and/or limph build-up) are, to use a metaphoric term , absorbing the pressure.
I can’t say better than that, and if it’s not clear, I apologize in advance.
I want to add an attempt of a more formal description of what I mean. This is in blue color, so those not interested in details can miss it- it is not essential, and could be confusing.
All of you have also to remember that I’m not a phisicist, and this is just a try for a “second level” reading, if you get what I mean.
Pressure (P) is what we want to use for deforming the tunica.
Pressure should act on volume (V) of tunica.
Changes in volume are (dV).
Deforming effect is D.
While the absolute value of D should be P/dV, if we want a relative measure, or index, we have to relate dV to starting V.
So: D= P/(dV/V).
If penis was only made of tunica, higher levels of P should lead to higher D values in a linear way.
But if penis was made of, in example, three different tissues, the higher pressure level could be not so linear; i.e., I suppose (a physicist or engineer should chime in) this:P = (P1+P2+P3)/3=(D *dV1/V1 + D *dV2/V2 + D *dV3/V3)/3.
Otherwise said, when clamping P is pressure hitting tunica entirely. When pumping, P is the median pounded value of those P(n) values- this is what we read on the pump-gauge.
Moreover, the maximum level of P that can be obtained is correlated to the mini-max of that these P(n) we want : the lower value of each max P(n) value.
This mini-max P(n) is, itself, dependent to the maximal D value we want on each tissue : the lower value of each max D(n) value.
Others things related to penis anatomy, observed by our thread-MEDS, can of course concur as well in limiting the maximum value of P that can be obtained, or the effectiveness of P on tunica deformation.