The same is true with liquid and dry measurements. Take a cup. Now double it and you have a pint. Double it again and you have a quart. Take a gallon and divide in four; that’s a quart. Divide a liter into four parts, and you have to call it either 2.5 deciliters or 250 centiliters.

Look at a clock; it has sixty seconds in every minute, and sixty minutes in every hour. You can divide a minute in half, thirds, quarters, fifths, or sixths and in every case, you are left with a whole number of seconds. No fractions or decimals.

Metric may be good for scientific and technical measurements with things that increase by orders of magnitude. For example, hard drive memory started out with bytes, than kilobytes, followed by megabytes, gigabytes and now terabytes. But when dealing with carpentry and recipes and other measurements used in the construction of props, you are not having to convert between units which are one hundred or one thousand times larger than other units. You are dividing things into halves and quarters and thirds. You want to be able to take a measurement with a ruler which gives you one or two whole numbers and a fraction. It is so much easier to say “this prop is one foot and three inches tall, two feet and five inches long, and three quarters of an inch thick” than it is to say “this prop is 38.1 centimeters tall, 73.7 centimeters long, and 19 millimeters thick.” Furthermore, when you look at a tape measure, the hash marks for the fractions of an inch are all different sizes, so you can easily see whether you are at 1/4 or 5/16. With a metric tape measure, you have ten tiny divisions per centimeter, all at the same height. Is that .7 cm or .8? Who knows! (Of course, the greatest sin is a tape measure with both metric and customary units.)

The system of inches and feet were developed from commonly experienced physical objects, like a human thumb and a human foot. Their subdivisions were developed to measure commonly constructed objects for everyday use. This is what we deal with in props; the construction of everyday items on a human scale. A meter, on the other hand, was derived as a fraction of the Earth’s diameter. How much more sense does it make to say “this bench should be as long as three of my feet” than it is to say “this bench should be large enough so that 3,187,000 of them will fit end-to-end from one side of the planet to the other, going through the center”? Balderdash!

Metric is a centrally-designed hierarchical system which is applied to the measurement of everything conceivable, while customary units are a collection of localized systems specifically altered to the items and entities being measured. It may be funny to dig up archaic names of measurements to ask rhetorical questions like “how many hogsheads in a morgen”. In reality though, you will never need to convert the measurement of a cask of wine to the measurement for a plot of land. As an aside, archaic units are not limited to the customary system; does anyone in metric still use a stère?

It may be tricky to calculate how many inches are in a mile, but you rarely need to use that conversion in day-to-day life. Finally, despite the often touted ease of converting from nanograms to kilograms to megagrams, scientists have settled on essentially using the kilogram to measure the mass of everything, from the sun to an electron. No need to convert anything!

This is not so much a case against metric, but an appeal for hybrid systems and specificity in measurements to the task at hand. There is no harm done if I build a bench using inches and feet while biologists measure the volume of a cell in micrometers. I don’t wear the same outfit as a biologist, and a biologist doesn’t use the same tools and machines as a props artisan. That would be absurd. Neither of us have to convert the volume of a cell to the height of a chair. That would be even more absurd. Both of us using the same system of measurements? That’s the absurdest.

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Large stationary tools which allow precision work did not appear with the birth of electricity. Though it may seem a table saw or band saw can only work off of an electrical motor, machines like these were common long before they needed to be plugged in. Running off of foot pedals, hand wheels, or a central axle driven by water, wind or steam power, these machines share many of the shapes, guards, rails and features of their electrical descendants.

This is from The complete dictionary of arts and sciences, Volume 2, by Temple H. Croker, Thomas Williams, Samuel Clarke, published 1765.

A collection of lathes circa 1765

The next few are from Amateur work, illustrated, Volume 1, by Ward, Lock & Co., published 1883.

Fret and scroll saws, circa 1883

Band-saws, 1883

Band-saw attachment for hand power, 1883

Combine circular and band-saw, 1883

I imagine these kinds of tools took two people to operate; one on the wheel and one moving the material.

Circular Saw, 1883

The following come from Wood workers’ tools catalogue, published by C.A. Stelinger & Co. in 1897.

Empire scroll saw, 1897

Ajax boring machine

Imagine if you had to tell people that your job was to operate a boring machine all day.

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What is Celastic?

originally uploaded by Trimper's Haunted House Online

Celastic was first trademarked in 1926. It was being used by the theatrical industry as early as the 1930s, and saw its most widespread use in theatres of all sizes by the 1950s. It appears to be one of the most popular prop-making materials of the ’70s and ’80s, and why not? It was used to make everything from masks to armor, statues to helmets. It reinforced other props, or simply gave them a smooth, flowing surface.

Celastic is a plastic-impregnated fabric which is softened with a solvent such as acetone or MEK. When it is soft, it can be manipulated into nearly any shape; it can be wrapped around forms, pushed into molds, or draped over statutes. You can cut it into strips or small pieces; Celastic adheres to itself. When it dries, it becomes hard again, thus retaining whatever shape you can manipulate it into. If necessary, it can be resoftened and further manipulated.

Here is an example of what passed for safety knowledge back when the use of Celastic was prevalent: “Rubber gloves should be used to keep the Softener off the hands. The liquid is not injurious under normal working conditions… Common-sense precautions will make the medium acceptable for any school use” (Here’s How by Herbert V. Hake, 1958). Of course, “not injurious” is not the same as “harmless”.

Acetone and MEK of course can be absorbed through the skin, and the fumes can cause neurological damage. As prop makers became more health-conscious and aware of the effects that cumulative exposure to solvents, especially strong ones like MEK, could have on their bodies, they began seeking out alternatives and scaling back the use of Celastic. Today, you’d be hard-pressed to find even a single practitioner using this material. You find one occasionally; their argument is that no other material can be draped as finely as Celastic, and if you take the proper precautions, you can protect yourself. There is some point to that; all chemicals can harm your body to some extent, and you need to be aware of how that chemical can enter your body, how much is entering it, and how to properly limit your exposure to it. If you wear the proper gloves and sleeves, respirator, goggles and face shield, and work with the solvents in a well-ventilated area (preferably some kind of spray booth or hood), working with Celastic would be no more dangerous than working with wood.

Of course, we rarely work alone in theatre; if one person is working with Celastic, than everyone is breathing the fumes. Prop shops are rarely the best ventilated areas, so the vapors can hang around long after everyone has removed their respirators. And of course with all the deadlines and time pressures, the temptation to take shortcuts in safety are always present; “I’ll just dip this one piece in Celastic really quickly; I don’t need to go all the way to my locker to get my respirator.”

Most prop shops these days seek to use the “least toxic alternative.” Whatever perceived benefits Celastic may have is far outweighed by the existence of less toxic materials that will accomplish the same goals.

Some of these alternatives are thermoform plastics which are softened by mild heat; they can be dipped in boiling water or blown with a hot air gun. One of the first to be introduced was known as Hexcelite; it was developed as an alternative to plaster for setting broken bones in a cast. Today, it is sold under the trade name of Varaform. Two other popular brands are Wonderflex and Fosshape. Wonderflex is a hard plastic sheet, while Fosshape is more of a plastic-impregnated fabric.

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• 16 oz. Claw Hammer
• 25′ or 30′ Measuring Tape
• 100′ Measuring Tape
• 12″ Combination Square
• Framing Square
• Bevel Square
• 8 pt. Hand Saw
• 12 pt. Hand Saw
• Back Saw
• Key Hole Saw
• 1/4″ – 1/2″ – 3/4″ – 1″ Wood Chisels
• Cold Chisel
• Box Plane
• Hand Axe
• Two Chalk Boxes
• Dry Line
• Line Level
• 24″ or 30″ Level
• Compass
• Angle Dividers
• 24″ or 30″ Wrecking Bar
• 10″ Vise Grip Pliers
• Pliers
• Diagonal Cutters
• Straight-head and Phillips-head Screwdrivers
• 10″ Crescent Wrench
• Nail Sets – Various Sizes
• Wood Files – Various Types and Sizes
• Sharpening Stone
• Tool Belt
• Assorted Pencils and Marking Crayons
• Plumb Bob
• Utility Knife and Blades
• Gloves
• Cordless Drill
• Large Ratcheting Screwdriver (Yankee)
• Tool Box

IATSE Local 44 is also known as the Affiliated Property Craftspersons Local 44; it covers workers in film, TV and independent shops in Los Angeles (though members work throughout the world). As such, the above list is specific to those employees. Still, it is a good starting point for propmakers in other situations, locations and fields. My own traveling prop kit includes some tools I can’t live without, and does not include some of the tools listed above. What does yours look like?

As a postscript, you will notice the list contains no tools for soft goods, sewing or upholstering. This is not an oversight; rather, these crafts are separate departments in the local, and thus have their own list of expected tools detailed on the website, which I may write about in the future.

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Inventables has a whole smörgåsbord of strange and interesting materials for props people. Squishy magnets, translucent concrete, aluminum foam, waterproof sand, rubber glass… I can go on and on, but the site begs you to just peruse everything for yourself.

Styrofoam has been a big boon to props artisans, but it brings with it a host of environmental concerns, both in its manufacturing (it is a petroleum-based product) and in its disposal (it will not bio-degrade for thousands of years). I’ve recently come across a foam made from mushrooms and bio-waste (technically, it’s made from the mushroom roots, which don’t contain spores and allergens). It seems promising as a potential replacement for some uses of foam, though I haven’t gotten my hands on a sample yet to test it out. Eben Bayer, one of the inventors and founders of the company, gave a TED Talk called “Are Mushrooms the New Plastics” where he goes into further details.

Along the same lines, researchers at the University of Nebraska-Lincoln are turning chicken feathers into plastic. It’s still a ways from being a usable product, but you can expect a whole host of non-petroleum-based and biodegradable plastics to be popping up over the next decade.

Shapelock is a new thermoplastic which becomes moldable at low temperatures (150°F). If you’ve ever used Friendly Plastic or Instamorph, this seems like similar stuff.

Finally, Sugru has been getting a lot of buzz lately. It seems similar to epoxy putty in its use and application, but it is a silicone, so it remains flexible, soft and waterproof.

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So who invented the hot glue gun, and how did it come to be? If we Google the phrase “who invented the hot glue gun”, we find the following results:

Google search for "Who invented the hot glue gun"

The first few results list “Robert Brooklyns” as the inventor. Let’s see what a Google search on him turns up:

Google search for "Robert Brooklyns"

When I did the search, Google returned around 83 results. All of them basically parroted the same sentence. Basically, one site (Answers.com is my guess) made this completely uncited statement, and it has been echoed throughout content farms and superficial sites across the internet. No one with this name shows up in a deeper search through books or patents, which seems surprising, given how important the hot glue gun is.

You may have noticed in the first image that a result shows up with an obituary for George Schultz, whom the Boston Globe calls the “inventor of the first industrial glue gun”. According to the Globe, he founded Industrial Shoe Machinery in Boston in 1954, which he sold to 3M in 1973. Somewhere along the way, he invented the Polygun, the “first industrial glue gun”. 3M manufactured hot glue guns under the name “Polygun” until 2006, when they changed the name to “Scotch-Weld”.

The earliest related patent I could find for George Schultz was for an Apparatus for Dispensing Thermoplastic Material. It was issued on June 2, 1971.

George Schultz's glue gun

The diagram shows a glue gun with a trigger, but the glue is held in an internal reservoir rather than fed through as sticks. While Mr. Schultz was certainly the inventor of a hot glue gun, he was hardly the inventor of the hot glue gun.

The Wikipedia article on adhesives has an uncited claim that thermoplastic adhesives were invented in the 1940s by Proctor and Gamble by a man named Paul Cope. Again, this becomes hard to verify, because innumerable content farms merely copy the Wikipedia article, and most of the search results are variations of this same initial claim (many have the same exact wording). At least we can find evidence that Paul Cope was a real person who worked at Proctor and Gamble. He even filed a number of patents having to do with improvements in packaging. Whether he had anything to do with thermoplastic glues seems to be a moot point, as mentions of thermoplastic adhesives can be found in literature and patents much earlier than that, as far back as 1907.

Perhaps the earliest proto-hot glue gun was this Plastic Extrusion Gun created by William R. Myers and Albert S. Tennant in 1949. The device was created for melting plastic and extruding it onto fishing hooks to manufacture fishing flies. The plastic was fed into the device as ribbons rather than as sticks, and it did not use thermoplastic adhesive. Regardless, many of the parts and components of a modern hot glue gun are there, and later inventors referred to the Myers and Tennant plastic extrusion gun quite a bit in their patents.

Myers and Tennant Plastic Extrusion Gun

In 1965, Hans C. Paulsen, working for United Shoe Machinery Corporation, was granted this patent for the Portable Thermoplastic Cement Dispenser. It predates Schultz’s invention by six years.

Paulsen's portable thermoplastic cement dispenser

That December, Popular Science ran an article about this glue gun, named the “Thermogrip”. The article proclaims “A black plastic pistol with an electrical heating element and an aluminum nozzle that extrudes hot-melt glue is one of the newest tools for home and shop.” I find the Thermogrip notable for its use of glue sticks and for the fact it was marketed and sold to home users, as opposed to previous glue guns which were tailored for specific industrial processes. I would consider this to be the first “hot glue gun” in the sense which we are most familiar today.

As with any invention, it is perhaps futile to try and trace its invention to a single person. The hot glue gun relies on a number of parts and components, such as the development of thermoplastics, the evolution of plastic extrusion guns, and the societal need for a portable device which accomplishes all of this. The modern-day glue gun we all know and love has any number of features and improvements which were not present in the earliest iterations.

That said, the hot glue gun was certainly not invented by a (perhaps imaginary) man named Robert Brooklyns, and hot glue was not invented by Paul Cope. This goes to show how easily an unverified claim can infiltrate the Internet. Remember kids, more search results in Google does not equal more reliability. An unsourced claim is still an unsourced claim even when it shows up on thousands of websites.

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Parts of a hammer

Your basic hammer is made of two parts: the handle and the head. The handle fits through a hole in the head known as the eye (or adze eye), and is held in place with a wedge. On newer hammers, the grip may be wrapped in rubber for greater comfort. The face is what strikes the nail or other surface you are hammering. Hammers used for peening, or shaping metal come in a number of varieties. A ball peen hammer has a peen with a hemisphere shape. A claw hammer has a claw used for removing nails or separating two pieces of wood.

Types of hammers

I gathered some of the hammers we have in our shop, which represent some of the more common types which are useful to the props artisan. From left to right, we have:

Claw hammer: Your basic carpentry hammer is useful for driving and removing nails into wood. It’s also the go-to-hammer for basic “hitting stuff”; I kind of cringe every time I see someone grab a ball peen hammer to knock something loose.

Rawhide mallet: Useful for non-marring blows, especially when working with leather, jewelery or other softer and delicate metals.

Lead mallet: These are used to hit steel without the risk of creating sparks. You can also get copper mallets for the same purpose.

Soft-faced hammer: The faces are made of soft materials, such as rubber or plastic, and are often removable and replaceable. These are used when you are hammering on or around decorative or finished wood to keep from marring the surface.

Tack hammer: Used in upholstery to drive tacks. One end is split and often magnetic to help hold the tiny tacks while driving them in.

Ball peen hammer: Peen hammers are used for shaping metal. Besides the ball peen, you may also find straight peen, cross peen, and point peen, among others.

Wooden mallet: Or carpenter’s mallet, used for furniture assembly or driving in dowels when non-marring blows are needed.

You can of course find any number of other types of hammers and mallets, with many variations in between. Prop shops will often carry rubber mallets, rip hammers and sledge hammers. Other types of hammers, such as bricklayer hammers or drywall hammers may also find their way into shops. Check out the Science and Engineering Encyclopedia for a comprehensive list of hammers.

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Front view of the brake

Again, I have to credit this post on Dave’s Sheet Metal Bending Brake for getting me up to speed on the best way to design a brake.

Side view of the brake

The piece of angle-iron is screwed to the worktable. The square tube is attached to the angle-iron by two small hinges, which are welded on. The tops of the bar stock, hinges and angle-iron are all in line with each other. Finally, I have a piece of wood which can be clamped down to the brake; the front face of the wood is lined up with the front face of the angle iron.

Sequence showing a fold being made

The metal is laid on the box tube and angle iron. The wood is clamped down. The fold will happen at the edge of the wood, so we mark the metal where we want the fold, and line that mark up with the edge of the wood. When you lift the handle, the metal bends with a nice sharp crease.

Here is a brief video of the brake in action making all the folds on one of the footlights.

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Likewise, France in the time of Moliere saw craftsmen building props. The theatre was controlled by the monarchy, which also controlled the various guilds, who enjoyed monopolies in their industries. Thus, if a play called for a chair or table which could not be borrowed, the specific furniture guild could be called upon to construct what was needed.

From a plate in Andre Roubo’s book on woodworking

Several societal innovations occurred which brought carpentry out of the guilds and more accessible to the average prop master. The industrial revolution brought standardized parts and mass production. This greatly improved the quality and amount of carpentry tools which were available to the general public. Tools such as highly accurate marking devices, truer saws, and mechanically-advantaged drills increased the speed and efficiency of carpentry to the point where a more generally-trained property master could now construct custom props out of wood for a show.

The second innovation, which is really an extension of the first, is the introduction of electrical power tools. Tools which relied on power were certainly available long before electricity; animal, water and steam power could drive a shaft in a large shop, which in turn, drove any number of large power tools. Electricity made it possible to escape the line and bring the tool anywhere. A prop master could now use a table saw or band saw in a basement of a theatre as long as they had an electrical outlet down there. If they needed to bring a tool to another part of the theatre, they could. The great leap forward came not just in the greater speed and efficiency of these tools, but also the ability to set up a shop in nearly any location. This innovation continued with the introduction and improvement of battery-operated power tools. These days, you can perform just about anything on a cordless tool as you can with a corded one.

These innovations should not be overlooked. If you’ve ever ripped multiple pieces from a full-length piece of plywood, imagine having to do the same thing with a handsaw. The sheer amount of carpentry which a props artisan can accomplish in one day is far greater by magnitudes than what was possible in the days before Vaudeville.

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Amy Slater cuts a fake goat apart

Artisans have a wide range of opinions on how to choose your tools. Some feel the cheapest tools are good enough, while others feel only the most expensive tools are worth your time. I believe it’s better to have the right tool for the job, rather than trying to improvise with the wrong tool. If that means you have to buy the cheapest one because your budget is small, so be it. Better to pound in a nail with a cheap hammer than the end of your cordless drill.

When you are building your tool collection, you will most likely feel tempted to buy all sorts of tools you see in the store or read about. If you wish to “audition” a tool to figure out whether it deserves a place in your toolbox, buy the cheapest version that will get the job down. If you use it to the point where it wears down and falls apart, you know it will be worth it to invest in a more expensive and higher quality version. You will also learn why it is a cheap version and which features and specifications to look for in your next purchase. If, however, that cheap tool sits around in your tool box for a year, unused, than you can feel good that you did not spend a lot of money on a tool which you don’t actually need.

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