Tag Archives: casting

Choosing the right disposable glove

First, I wish to offer a caveat; I don’t write much about safety, because it’s a highly complex area, especially once you start talking about safety around chemicals. I’m not an expert, and if you are in a workplace situation, there are actual regulations, standards and laws that need to be followed. The last thing I want is someone’s sum total of knowledge about safety coming from “Eric Hart’s Props Blog.” Still, the home hobbyist may not know where to look for information, and the prop shop employee may not know what questions to ask their employer, or what their employer is responsible for providing. Thus, what follows is not a guide for choosing the right disposable glove; rather, it is a guide to what questions to ask and what information to look up to learn which disposable gloves are best for each situation. All the safety data in the world is useless if we don’t know what information we are trying to find, or even that we need to find certain kinds of information. Often, we don’t know what we don’t know.

Dozens of companies make disposable gloves, offering hundreds of combinations of materials, thicknesses and liners. You need to find the permeation data for the specific gloves you are using. This will tell you how long it takes for specific chemicals to work their way through the glove and onto your skin.

No single glove will protect you against every chemical. There were approximately 50,000,000 chemicals registered by the CAS on September 7, 2009, with more being added at the rate of twenty-five per minute. Luckily in theatre, we only use a small percentage of those chemicals. If you work at a theatre or shop in the USA that employs ten or more people (that’s counting the whole theatre, not just the prop shop), then it is subject to OSHA regulations, and your employer is required to inform you of any toxic chemicals you may be using.

As a general rule of thumb, you should be wary of rules of thumb when it comes to safety. But a good rule of thumb to follow in safety is “don’t get stuff on you, and don’t breathe anything that isn’t air.” Choosing the right glove falls under the “don’t get stuff on you” part of the rule. Gloves are necessary because many chemicals can be absorbed through the skin. Chemicals commonly used in prop shops that can be absorbed through the skin include solvents and epoxies. Solvents don’t just include pure solvents like acetone, xylol and mineral spirits, but also any product that includes solvents: spray paints, cleaners, adhesives, etc.

Another good rule of thumb is that latex gloves don’t stop any chemicals. They can keep your hands dry, and they’re great for keeping blood and other bodily fluids from getting on your hands. They’re also useful for the reverse: keeping your own sweat and oils from getting onto your work surface. But as far as working with any sort of industrial or household chemicals, they may as well be invisible.

Notice how I mentioned household chemicals above. Just because you can buy something in a grocery or drug store doesn’t make it safe to work with without proper protection. For example, many cleaners like Windex, 409 and Simple Green use a chemical called 2-Butoxyethanol. The toxic exposure level of 2-Butoxyethanol is less than that of acetone and hexane, placing it in the category of “highly toxic” chemicals. When you start looking at permeation charts for popular glove brands, you see a trend; latex gives you no protection, while neoprene and vinyl will offer only several minutes before exposure begins. If you are using anything other than nitrile, you are exposing yourself to a highly toxic chemical.

If you are using a glove and the substance is splashing or spilling onto your bare arm, it defeats the purpose. Make sure you are wearing sleeves that offer similar chemical protection, or use longer gloves.

Many chemicals we use for prop making are toxic through skin absorption. An example is any of the two-part epoxies we use: sticks of epoxy putty, five-minute epoxy glue, epoxy coatings for fiberglass and carbon fiber, epoxy resin for casting. Epoxy is a sensitizer, which means our bodies do not react to it on the first exposure. Rather, it is on the second or subsequent exposures where we develop what is essentially an allergic reaction. It can even be after decades of using a product before one reacts to it. But reaction can be severe. Here is a chilling but not uncommon description of a reaction:

Open, oozing, and itching insanity hives virtually all over my body and my eyes literally were swollen shut for a week on two separate occasions. Recovery, each time, took better than a month.

Once developed, it is not reversible, and occupational physicians may advise you to not only never use epoxy again, but none of the “two-part” chemicals in that category. No more Smooth-On products, Great Stuff, A-B foam, etc. If you make your living as a props artisan, you pretty much have to do all your molding and casting out of plaster.

It is important to note that permeation data charts tell how long it takes for a chemical to permeate through a glove. This implies that no glove will offer permanent protection; they are called “disposable” for a reason. In fact, the most a glove gets tested is for 6 hours. If you use a pair of gloves all day, don’t set them aside for the next day. In fact, you should throw the gloves away. Trying to stretch the use of a pair of gloves to save money may seem thrifty, but it is actually counter-intuitive. The same is true of any safety measures and products you use. If you use or reuse them improperly, you get the worst of both worlds; you are spending money but not keeping yourself safe. If you feel you are spending to much money on safety equipment to make props, the best solution is to stop making props. You don’t go scuba diving without an air tank. We often get in situations where the easiest solution seems to be to continue on and finish a prop; it’s late and you’ve run out of gloves, and all the hardware stores are closed, and all you need to do is get one more coat of epoxy on so it can cure by the morning and they can use the prop in rehearsal. When you get to those situations, remember this: Your goal in life is not to finish that single prop. Your goal in life is to build props for the rest of your life. Taking shortcuts now will affect your health later on. No prop in the existence of humankind has ever been more important than your health.

A good shop foreman will be consistent in his or her purchasing of disposable gloves, so you don’t have to hunt down the permeation data every time he or she buys a new brand.

In conclusion, don’t get stuff on yourself. You should know what is present in any material or substance you are working with. If it includes chemicals that can be absorbed through your skin, you need to find out what glove will offer protection from that chemical, and how long it will offer that protection. Remember that gloves from different companies may differ in their permeation data, even if all the stats on the box seem the same.

Monday’s Rockin Links

I spent the weekend with my wife at Monomoy Theatre, where she is the guest scenic designer for two shows. I wish I could turn that into a segue for today’s blog post, but unfortunately, it just means I only had time to hunt down some links for you all. Maybe at the end of the summer, I’ll have a “what did you do on your summer vacation” post to hear your stories about propping summer stock shows and what not.

  • Here is an interview with Paul Alix, one of the model-makers on the new Predators movie. It also includes a video of him demonstrating some casting techniques.
  • Speaking of casting, here is Sarah Gill casting a sheep’s head. It’s from 2007 but still loads of fun.
  • Design*Sponge has great pieces on the histories of certain objects. Two recent ones include the history of the fork and the history of the curule (an x-stool, or folding stool).
  • British Antique Furniture Restorers’ Association has loads of information on antique furniture, including a glossary of terms used to describe pieces and parts.

How to make a breakaway telephone

One of the trick props we needed for The Book of Grace was a phone which John Doman smashed during every performance. We decided that the phone receiver would remain real, but the part it hung on would be cast from plaster. It would all hang on a wooden base, and a collection of “phone innards” will be held inside the plaster part, so when it broke, an assortment of metal bells, chip-boards, and other electronic components would be left hanging on the wall.

Weigh out the silicone
Carefully weigh out the silicone

We made a two-part silicone mold of the phone. Making a two-part silicone mold is beyond the scope of today’s post. However, I did get a photograph before the pouring of the first part. At this point, Natalie Taylor Hart took over the project.

Preperation for making a mold of the phone
Preparation for making a mold of the phone

Normally, the next step is to make the second half of the mold from the back of the phone. In this case, the shape of the back was far more complicated than what we needed, and we were worried the plaster cast would be too thin. So we took the first part of the mold and built up the thickness we wanted to achieve out of Klean Klay. The Klean Klay is the yellow substance in the photograph above, and remains flexible like plastiline. It also does not contain sulphur, which reacts with the silicone mold-making compound. The mold still needed some tweaking, so Natalie carved directly on the silicone to perfect it.

A view of the mold
A view of the mold

We wanted the color of the phone receiver to match the back part, which was the sort of taupe that most appliances from the late twentieth century came in. When the plaster phone gets smashed, the broken edges would show up white. Thus, we needed to dye the plaster while it was still in liquid form. Natalie found that a tablespoon of Rit tan dye in the mix made the best color match.

Adding dye to the plaster mix
Adding dye to the plaster mix

Natalie sifted the plaster into the water until tiny islands of plaster began to form on the surface. Once she had made a few phones, she had the exact measurements of both plaster and water marked down.

Combining the plaster into the water
Combining the plaster into the water

Next, she let the plaster sit in the water for about 30 seconds. “Wetting” the plaster allows it to mix more thoroughly.

Letting the plaster wet up
Letting the plaster wet up

With such a small amount, she mixed it by hand. This also gave her a tactile way to ensure all the lumps were worked out of the mix.

Mixing the plaster
Mixing the plaster

Natalie discovered the best way to pour this particular mold was to slosh plaster over the top half before putting it together. It was important to get plaster in all the cracks and crevices or the strength would be compromised.

Pouring the plaster into the mold
Pouring the plaster into the mold

The phones set up overnight, but they actually took two to three days to fully dry. We could not get any kind of adhesive to keep the plaster parts onto the bases until all the moisture was completely out. We ended up needing around 40-50 phones for the run of the show, but since we could cast more than one a day, we could make them throughout the run rather than all at once.

Phones
Phones

Finally, here’s a video showing the end result. This was taken earlier with a different phone model, before they changed it to the slimmer model.

Fake ‘n Bake

I would like to introduce you to the newest blog about props: Fake ‘n Bake. My friend, Anna Warren, details the projects she crafts and constructs at the Milwaukee Repertory Theater. She specializes in fake food craftsmanship and casting and molding. Her articles so far are well-documented and chock full of photographs.

TV Dinner
A fake TV Dinner made by Anna Warren

The peas in that picture above? Mardi Gras beads. Check out the Fake ‘n Bake kitchen for how she made the rest. If you leave a comment there, tell her I sent you!

Dragon Skin

This week, at the Public Theatre, we begin working on some props for The Bacchae. Since there is going to be a dead corpse which is picked apart and torn up on stage, Jay Duckworth has ordered some “Dragon Skin” from Smooth-On to experiment with.

Many of us in the props world are familiar with Smooth-On and their range of products for molding and casting. My father, a potter in Pennsylvania, has been using their polyurethane for years in his mold-making, and they’ve really pushed some new products for theatrical purposes in the past decade or so.

A Silicone Severed Head
A Silicone Severed Head

But wait, there’s more! Their website isn’t just some bland information portal. They have a treasure trove of guides, tutorials, and instructions for using their products. On the special effects and propmaking section you can find step-by-step video sequences, photo sequences, and examples of what other people have done with their products.

You can also find a Smooth-On video channel over at YouTube. This contains many of the same videos showing molding and casting with their products as their website. They also have a list of “Favorites” showing videos from other users making and casting molds.