Use a Third Hand

I used to own a Leatherman Multi-Tool. It was one of my favorite hand
tools, mostly because of the pliers. It’s the most useful thing about the
tool beside the knives, which can also be found in any pocket knife. Pliers
come in handy for a variety of chores around the shop (and in daily life) and I
use them all the time. Invariably, however, I find myself with some pesky item
in one hand while trying to unfold the Leatherman; the bad part about using
this tool is that you often need a third hand to open the thing.

In time, I replaced my trusty Leatherman with the military version of
the Gerber Multi-Tool which can be opened one-handed and with just a flick of
the wrist. It lacks the more plier-like handles of the Leatherman, but the need
for a third hand has been eliminated from the ready implementation of its use.

But this article isn’t about the various pros and cons of

  Kevin Matthews, CO, uses a surge tank in the vacuum line for control.
  Kevin Matthews, CO, uses a surge
tank in the vacuum line for control.
  Images: Kevin Matthews

I was reminded of the occasional need for a third hand when I was out
and about in Texas and visited a very talented practitioner named Kevin
Matthews, CO, at Advanced Orthopedic Design in San Antonio, Texas. There are
still a handful of practitioners who are as much technician as clinician and
Kevin is one of the more creative practitioners on the bench. He showed me an
interesting way to apply the critical “third hand” to one of our more
challenging fabrication jobs, molded leather gauntlets.

Create a vacuum seal

The need to stretch wet leather in one direction and then another while
stapling it in place requires a technician and a half. Because you can’t
really have half a technician working on one job and the other half working on
another, this becomes a two-person job. These devices are time consuming enough
without pulling another valuable technician off of whatever he’s working
on to stretch or staple for another technician. This is where Kevin has thought
to use vacuum power to assist him in this task.

Whatever method of molded leather fabrication you employ for the design,
you will come to a point where you need that extra hand. When you do, try this
simple and easy solution: Apply a heavy duty bag over the cast, seal it above a
vacuum line and turn on the vacuum. As the air is sucked out of the bag, pull
it forward toward the anterior to smooth out the wrinkles in the bag and then
you can begin to work the wrinkles out of the leather. When performed
correctly, the bag acts like an extra hand holding the leather in place while
you are free to use any number of tools to force the leather to bend to your

Of course you need to remember that all leather has a grain — one
way that it will stretch and the other direction that it won’t. Anyone who
has ever worked leather, especially molded leather, understands this and will
work it into the design and layout of the fabrication. Since leather will lay
along the posterior of the cast (down the gastroc, across the heel and to the
tip of the toes) without stretching at all, you might want to make certain that
you are stretching the leather forward toward the ankle. Take advantage of the
lay of the land and use the grain of the leather to make your job easier.

Ensure bag durability

Here are a few tips that you might find useful in adapting this
technique to your process. To begin with, a heavy duty plastic bag is required
to withstand both the pressures of the negative vacuum and the pressures of the
tool you use to work the leather. My friend Kevin has found that trash
compactor bags work perfectly. They are designed to be used under similar
pressures as we will put them through and they’re relatively cheap. If you
accidentally pop a hole in one you’re only out a few cents.

  Matthews uses trash compactor bags to help hold the molded leather in place.
  Matthews uses trash compactor
bags to help hold the molded leather in place.

On that note, there are a couple of things you can do to avoid popping
the bag. First, make sure that you don’t have any large voids between the
cast and the vacuum pipe that might suck it in too far, causing it to rupture.
Some stocking scraps usually work best since you need to make sure the vacuum
stays constant and the hole isn’t blocked.

Another thing you can do to prolong the durability of the bag is to
employ a variety of tools to work the leather that are smooth and don’t
have any sharp edges. A small, hard rubber roller is a great tool. You can
force the leather to stretch forward in large areas all at once. Such a tool
can be found at any craft store and is sometimes used by calligraphers and
scrapbookers to roll out ink and clay. Also useful is any round metal ball, as
can be found on ball peen hammers. These are handy when trying to shape the
leather around the complex curves found at boney prominences and flairs. Butter
knives, spoons and any other tools with a smooth hard edge can make shaping the
material easier.

Remember that when using these tools, especially the ball peen hammer,
be careful of the plaster cast underneath the leather. It takes a fair amount
of pressure to damage it under normal circumstances, but you can reduce the
surface of the cast to dust if you’re overzealous. Firm pressure should be
enough to get the wrinkle to take the shape of the cast underneath without
breaking the mold.

Have a surge tank

As far as the vacuum system is concerned, it’s best to have a surge
tank in your line. You will turn the vacuum on and off during the course of
working the leather and a surge tank makes that kind of controlled vacuum
possible. It’s all about technique and finesse. Controlling the flow of
air will enable you to relieve pressure on the leather, adjust position and
reapply pressure again, all very quickly and smoothly.

When you have worked the leather as best as you can, it is perfectly
acceptable to allow it to dry for a few hours and then try it again. Like any
molded leather operation, it may take two or more applications to get the shape
right but that’s normal — and one of the downsides of molded leather.

This method will allow you to do the process by yourself without
drafting another technician onto the project. Using this third hand can make
you more efficient and valuable as a technician, and the finished product might
even be better than what you were capable of before.

Steve Hill Steve Hill, CO is secretary and co-founder of
the Orthotic Prosthetic Technological Association and president of Delphi
Ortho, an orthotic consulting firm based in Asheville, N.C. He serves on the
American Orthotic and Prosthetic Association Assembly Planning Committee and is
a Board of Certification/Accreditation, International Facility Accreditation

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