While having breakfast at Palm Beach Farrier Supply last winter, some of the other regulars suggested that I interview local farrier Curtis Burns about his shop and business, Burns Polyflex Shoe. It was a good suggestion. Burns is my kind of guy — a smart, outside-the-box thinker, who is constantly working at improving the status quo.
Burns originally had his sights set on being a racehorse trainer. To succeed, he found it necessary to do most of the work himself, including shoeing the horses in his training barn. Soon the word got out that this young guy was a pretty good plater, and he became a farrier by default. When one of his clients had a horse plagued with recurring lameness problems, Burns designed and made a polyurethane shoe to help him. The rest is history.
In 2002, Burns and his wife, Diane, started making and selling his Polyflex shoes for the racehorse market. The Polyflex shoe is a polyurethane shoe that is unique in that it has a metal rod in its core and is designed to be glued on. He has recently expanded into the sport horse industry with a line of shoes suited to those disciplines. He estimates that he has glued on over 2,000 pairs of shoes with the horses achieving amazing success.
Burns agreed to share his techniques with me. I have frequently observed other farriers gluing on shoes and, over time, have seen small improvements in tools and techniques. Watching Burns was like hitting the jackpot in Las Vegas. His innovations just kept coming.
This article is a combination of my experiences gluing on shoes and the improvements Burns has made in the process. It is meant to detail some of the best ways of successfully dealing with horses, clients, owners and veterinarians for a favorable outcome.
Burns gets immense gratification from teaching farriers how to successfully glue on his shoes. When someone embraces his ideas, Burns feels as if he’s just won the derby. He has developed a system that is very reliable and easy to follow. The secret is to stick to the plan, follow the steps (without leaving any out) and pay attention to the details.
Before you get started, you may have to go on a shopping spree and stock up on supplies. Here is a shopping list of the equipment and supplies that Burns uses. You can get by with low-tech tools, but if you are frequently gluing on shoes, good quality tools will make the job easier and result in better outcomes.
Unless noted, these items can be purchased at big box hardware stores, farrier supply shops or online.
Curtis Burns is very careful in preparing feet for glue-ons. He uses a die grinder with a 3/4-inch drum sander to clean the hooves. He then uses a Dremel tool with a tungsten carbide cutter to finish the heels. After the foot has been dried with a butane torch and brushed with a wire brush, he’s ready to begin gluing on the shoes.
Aluminum or acrylic shoes are normally used for glue-ons. Steel shoes can be used, but keep in mind that steel shoes rust, so the bond between the shoe and the acrylic will be compromised in hot, humid conditions. For those conditions, aluminum or polyurethane may be better choices.
Keep an open mind when choosing shoes. Each material has its pros and cons. As Burns says, “Don’t become a one-trick pony.” If your objective is to stabilize the foot and stop the heels from moving, metal is better. However, over time the metal shoe will cause the foot to contract from lack of movement. If you want the heels to expand and contract normally, then the open-heeled polyurethane shoe is a smart choice.
Burns prefers to use the polymethylmethacrylate adhesive, which is manufactured by Lord Chemical and is sold and distributed by companies under their own brand names. Burns has tried them all and settled on the Equilox brand. Equilox comes in several formulas. The original, slow-setting Equilox I (EI) and the fast-setting Equilox II (EII) are the most popular. At 70 degrees EI, the slow set, will set in 6 to 8 minutes and cure in 10 to 13 minutes. EII, the fast set, will set in 4 to 6 minutes and cure in an additional 4 to 6 minutes. Set and cure times will rise and fall with the temperature. Burns prefers to use EII regardless of the outside temperature.
Equilox also comes in many different container options. Because Burns glues on so many shoes, he uses the 420-millimeter cartridge with the dispensing gun. The cartridge comes with a threaded opening for use with mixing tips. Few farriers elect to use the tips because they are expensive. Before using a cartridge, Burns cuts the threaded portion off with his band saw and grinds the end smooth.
Now, with just two small openings on the end, cleanup is a snap. Equilox is also marketed in 1- and 2-ounce, hand-mixing containers. These smaller containers may be more appropriate for someone who only occasionally glues shoes on. The 1-ounce container is enough for a small foot. For a larger foot, you will need the 2-ounce container.
Burns uses Equine Slipper Boots to keep the prepped hoof clean while the shoes are being prepared.
Keeping It Cool
Burns stores his Equilox in a full-size refrigerator at his shop. He transfers just what he needs into a portable fridge housed in his shoeing trailer. It is important to remember that the temperature of the material as it is applied to the foot is critical. If you keep it in the refrigerator all night and then put it in a warm rig for hours, it may become too warm to use. Also remember to put the cartridge back into a cool place when you are preparing the second foot if it is extremely hot, or when there is a delay between applications.
While on the subject of heat, note that you should grind the hoof surface of aluminum shoes before gluing. The friction from grinding produces enough heat in the shoe to cause uneven setting of the adhesive. After cleaning the shoe, chill it to dissipate the heat for better results.
Variable Temperature Heat Gun
When you are gluing shoes on in the cold, it is a good idea to have a heat gun handy. After the Equilox is in place on the foot, use the heat gun at a low setting to gently warm the material. This will jump start the bonding of the Equilox and dramatically speed up the process. Use good judgment on the heat setting and keep the gun moving for best results.
Keep in mind that Equilox sticks to anything that it comes into contact with. Reliable gloves are necessary to protect your skin from contact. I prefer 4-millimeter powder blue nitrile gloves. They are available from a number of sources and cost from 10 to 15 cents per pair.
Lung And Eye Protection
If you are going to be grinding on hooves, a high-quality respirator is a good investment. A respirator will protect you from inhaling pathogens that become airborne from the grinding process. I don’t know enough about respirators to make a recommendation, but keep in mind that filth in the air is a problem and could affect your health.
Eye safety is also one of my ongoing soapbox topics. Put on a good pair of safety glasses whenever you do any grinding. The probability of severe eye injury is high if you choose not to wear safety glasses.
Curtis Burns places Equilox on a shoe from heel to heel, using a tongue depressor. He then places the shoe on the foot. He stresses that it’s important to do this with the Equilox at the right temperature for the conditions you’re working in, and to place the shoe exactly where you want it on the foot before the Equilox begins to set.
It is important to have accurate measuring tools to precisely determine the dorsal wall angle and toe length. I used the Ward and Story angle gauge very happily throughout my career. To measure toe lengths, I relied on the 6-inch spring divider sold by Washoe Valley Farrier Supply. It is important to modify it slightly so that it does not irritate the coronary band. With minor modifications it will provide years of service.
I was not familiar with the measuring tool that Burns uses. It is a Precision Hoof Pick and is made and sold by Precision Pick online and through distributors. It looks like a conventional flat metal pick with a flat metal handle. It has a measurement scale on both the pick and the handle. After a conventional pick is used to gently and thoroughly clean the foot, it is used to measure the distance from the bottom of the medial and lateral sulci to the plane of the heels. As we know, the entire hoof capsule is pliable and can distort, but the frog and the sulci remain the same regardless of what the rest of the foot is doing.
This measurement is very reliable in determining the medial-lateral balance. Care must be taken when cleaning the sulci to make sure you don’t thin the horn. If disease is present, be careful not to injure the foot. The measurements on the handle are used to measure toe and heel length. The flat sides of the handle are useful for checking wall flares. It is such a good idea that I wish I had thought of it myself.
Die Grinder With Drum Sander
Burns uses a Makita GD0800C 1/4-inch die grinder for part of the cleaning process. Its speed ranges from 7,000 to 28,000 rpm. It costs about $215 and is easy to find. If you are price shopping, you will find that it costs twice as much as its single-speed brother.
Curtis Burns gets mutliple uses out of his Dremel tool. He uses it to grind the shoe smooth before he puts glue on it (right), and also to clean up around the edges when he’s done. He uses an older, duller bit for the latter part of the job.
I recommend spending the extra money. The option of slowing the speed down lets you vary the texture of the wall and sole. Slowing the speed also makes the grinder-sander combination safer to use. You will learn that it is indispensable after you have used it for a while.
Burns teams his die grinder with a 3/4-inch diameter drum sander using 50-grit sand paper. He uses this cylindrical grinding drum for cleaning the sole and wall. It is available from big box stores or on Amazon.
Dremel Tool With Tungsten Carbide Cutter
For the final prep before drying the foot, Burns relies on his Dremel tool, equipped with a structured-tooth tungsten carbide cutter. The top-of-the-line model is the 8200-2/28 12-volt cordless model. It has good battery life and eliminating the hassle of the cord is priceless. If price is an issue, the corded models are cheaper. Do not buy the hobby model because it will not hold up for this type of work.
The body of the tungsten carbide cutter, # 9931 is a 2-inch long, 1/4-inch diameter rod that is tapered on the end. It has small carbide pieces bonded to it. This grinder is perfect for sculpting the heels. Burns keeps two on hand. One is new or slightly used and is used to clean the heels before gluing. The other is one that has seen a bit more use and is now used to finish the foot and shoe after the glue-on procedure. It is the same rotation farriers use with their trim rasps and clinching rasps.
Burns uses thin foam strips with adhesive on one side to prevent sole pressure. He buys the material and cuts it into 3/8-by-1/8-inch strips, each 12 inches long. They are applied to the inner rim of the shoe when gluing a shoe on a foot with sensitive soles. It prevents the glue from creating pressure on the sole and can mean the difference between success and failure. This material is also great for making a drainage line in quarter-crack repair.
Burns uses 6- or 8-ounce cups to mix the Equilox. Both paper and plastic cups work fine. Standard drugstore tongue depressors are also used for mixing the material, as well as spreading it on the shoe and foot, and for cleaning off any excess material. Cut the tip on one end to a 45-degree angle to remove any excess under the inner edge of the shoe.
Equine Slipper Boots are used to keep the prepped foot clean while the shoe is being prepared for gluing. They are made with blue cordura sides, a thick leather sole, and Velcro closures. They are very easy to get on and off fast. They come in small, medium and large sizes. It is a good idea to carry all three sizes. They are available from Dover Saddlery for $39.99 per boot. Burns cuts a leather insert that fits just inside the boot. He can take the insert out and clean it, which provides a clean environment for the next foot.
This small torch is used to dry the trimmed foot before gluing. Burns likes the Bernzomatic brand, which can be found in the plumbing department of most hardware stores. It has an adjustable flame, is refillable and is very reliable. The butane torch produces a small flame of 2,500 degrees and is adjustable.
You may be familiar with the plumber’s propane brazing torch, which is commonly used to soften hard feet. That torch produces a large flame and temperatures of 3,600 degrees. It is safe when you are using it on a hard, untrimmed sole, but is dangerous to the trimmed live sole. Do not use your propane torch for drying the trimmed foot.
A standard hardware store brush works well and is available at all farrier supply stores.
Copper sulfate is a chemical compound also known as blue vitriol or bluestone. It is very good at killing bacteria. It is easy to obtain at hardware stores where it is sold in crystal or powder form to kill aquatic plants in ponds. If you can only find it in crystal form, crush it or put in a coffee grinder to reduce it to a powder. Burns adds it to the Equilox before mixing to control the bacteria found at the adhesion area.
Play Dough And Keratex Putty
Play Dough, the children’s modeling compound is made of water, flour, salt, boric acid and mineral oil. Keratex is the brand name of a line of hoof-care products from England. Keratex Putty is a medicated wax that works well in filling cavities to keep out debris and keep the area healthy. When Burns comes across a cavity that will be under the glue, he fills it with one of these products rather than filling it with adhesive. If the area is sensitive and on the sole, Burns uses Play Dough. For cavities in the wall, such as white line sites, he uses Keratex putty.
Burns and I both like Mustad’s Edge Adjustable Hoof Tester. It has a sliding bar for easy adjustment and has a little give in the handles, which increases sensitivity. I think I have tried just about every hoof tester available and like this one the best.
Cordless Drill And Hoof Buffer
The combination of any of the major manufacturer’s 18-volt cordless drills and Farrier Product Distribution’s hoof buffer makes a safe and effective way of removing the unfinished horn from hooves. Burns uses his hoof buffer for both preliminary and finish sanding. He runs the buffer in both directions on the foot for a much more even finish.
I used to tell my associates that to get to where you want to go, you have to first know where you are. By that I mean that you must make a thorough assessment of your client’s horse before you ever lay a hand on it.
Get a history and write it down. Take the time to talk to the owner, trainer, groom, veterinarian or whomever may have pertinent information. Jog the horse on a straight line and in both directions in a circle on a lunge line.
If possible, take a video of the horse. Since we all have such short memories, there is no way we can remember exactly what the horse looked like during the exam. The video camera has a better memory than an elephant. We have entered the digital age. Make use of it to further your business.
The next step is the hands-on examination. Start by walking around the horse and studying its feet. I ask myself six basic questions.
Does he look long?
Does he look short?
Does his angle look high?
Does his angle look low?
Does the foot deviate medially?
Does the foot deviate laterally?
Pick up the horse’s feet, clean them out thoroughly and record the lengths and angles. Pay attention to the health and condition of the feet. Study them to determine if they are symmetrical. Ask yourself if the visual information agrees with the measured information.
Once again, pick up the feet and this time do a thorough exam for soreness using your hoof tester. Only then are you ready to start trimming.
You should have a plan for what you want to accomplish in mind at this point and be able to visualize the finished job in your mind.
Although farriers have been trimming horse’s feet for centuries, there is an ongoing discussion of what constitutes a correct trim.
When a foot is properly trimmed, the coffin bone within the hoof capsule is aligned with the ground. On a radiograph, the medial and lateral branches of the coffin bone should be the same distance from the ground, so that a palmar angle of 3 to 5 degrees is present. A horse that is 15.2 hands to 16.2 hands should have a sole thickness at the toe of between 1/4 and 3/8 inches.
All flares and deviations of the wall have to be corrected so that pressure on the wall is uniform. The wall should be trimmed circumferentially from heel to heel at the junction of the thick live sole.
Trim the foot as if you were preparing it for a nail-on shoe with these criteria in mind. This is a very brief instruction but covers the important points of trimming a foot correctly.
Holes, Sore Spots And Nail Holes
When trimming the foot, it is important not to leave any pockets or depressions on any area of the foot where the Equilox will make contact. These may result in pressure points that will cause soreness. Fill any pockets that do exist with Play Dough. If you have old nail holes in the wall, do not open them up at the bottom. Open the hole at the top where the clinch was, so air can get to it.
After the foot is trimmed it is time to select and fit the shoes. Burns’s own Polyflex line of shoes have open heels and are designed for use with racehorses or sport horses. They have a steel rod in the center, which gives them memory so they can be shaped. He has also tweaked the formula so the bonding with Equilox is excellent. Although he is normally called upon to apply glue-on shoes, he stresses that he always chooses between glue-on and nail-on shoes based on which one will work best for a particular horse.
The technique for shaping his shoes is the same as if they were made of metal or acrylic, or if you were nailing them on instead of gluing them. Take great care to get the fit correct at the heels. Ideally you want about 1/8- to 3/16-inch of shoe behind the heel. If you are gluing on clipped shoes, bend the clips over to meet the wall. If you don’t, Equilox can get behind the clip, and no amount of hammering is going to make it sit flat against the wall.
After the shoe is shaped, it is necessary to thoroughly prep the hoof surface of the shoe. Burns uses his Dremel tool to clean it. He does not touch the surface after it is cleaned to avoid leaving oil residue from his hands, which can interfere with bonding. With a metal shoe, use the butane torch to burn off all the oil for even better results.
Cleaning The Hoof
After the foot is trimmed and the shoes are fitted, the foot must be prepared for the gluing process. The three operative words for success are clean, dry and fast. Keep these in mind. Burns has a three-step process to accomplish this.
Step 1. Use the cordless drill with a large drum sander to thoroughly clean the wall.
Step 2. Burns uses his Makita 1/4-inch adjustable speed die grinder with the 1-inch drum sander and coarse sandpaper for further work on the wall. He also uses this grinder on the sole.
The speed of the grinder is set at the lowest setting. There are two reasons for this. First, the slower speed gives you a rougher surface so more bearing surface is created. Second, occasionally the bonding on the sleeve will fail and fall apart. It is much safer for everyone involved if it is rotating at a slower speed when its flies apart.
Burns switches to his Dremel tool, fitted with the 1/4-inch structured-tooth tungsten carbide cutter to finish the heels to perfection. This cutter is tapered at the end so it is able to get into very small spaces for cleaning and shaping. Very small bits of carbide are bonded to the shaft, producing a rough grinding surface. This rough surface enables the Equilox to adhere well.
Step 3. The last part of the process is drying the foot. This is done with a butane torch. It is very safe when used with discretion. Keep in mind that it is possible to destroy sensitive tissue if it is not used carefully. Burns passes the torch over the foot and then brushes the foot with a wire brush until all debris is gone. When the foot is clean, he puts the hoof in the cloth boot.
Now, the foot is prepped and wrapped and the shoe is shaped. We have two decisions to make. First, we must decide if the shoe needs to have a foam strip applied to the inside edge of the branch to prevent adhesive from contacting the foot. If the foot you are shoeing has a thin sensitive sole, the foam strip will keep the adhesive off the sole and prevent pressure which could compromise the job.
Next, we must decide whether to administer a sedative. By this point, you should have a clear indication of the disposition of the horse. If you feel there is a good chance it is going to blow up as the adhesive is setting, it needs to be sedated before you go on.
A high degree of cooperation is required when the shoe is actually being glued to the foot. If the horse takes its foot away before the glue is set, you will have to start over.
My motto is, “Prepare to succeed.” Do not go forward if there is a good chance the horse is not going to stand.
Before putting the adhesive on the shoe, go through your checklist.
- Is the horse happy, quiet and standing on a hard, clean surface?
- Is the foot prepared properly?
- Is the shoe shaped, prepped and cool?
- Is the adhesive at the correct temperature?
- Do you have gloves on, and are the mixing cups and tongue depressors ready?
Squirt three to five dabs of Equilox and approximately an ounce of copper sulfate into the bottom of an 8-ounce paper or plastic cup. Stir vigorously for one minute, and then apply uniformly on the shoe from heel to heel.
Applying the Equilox mixture to the shoe is the important part. Let me stress that. If the ambient temperature is above 70 degrees, you must get the Equilox on the shoe and the shoe on the foot in 30 to 60 seconds. It is imperative that the Equilox does not start to set before the shoe is on the foot. If you are slow and the Equilox begins changing texture, stop and discard it. In this situation, the chances of getting good adhesion are greatly diminished. The prudent thing is to try again — and be faster.
The grandfather of the glue-on shoe was Eddie Watson. The late Virginia farrier, a member of the International Horseshoeing Hall Of Fame, mixed Equilox with shredded fiberglass to glue on his shoes. He reasoned that the fiberglass gave the Equilox mass and would prevent it from being squeezed out when the shoe was pressed onto the foot. But Burns has found that the shredded fiberglass is not necessary. Equilox was first developed to bond metal pieces together in the automobile industry. Tiny glass balls are mixed into the product to prevent the adhesive from being squeezed out. I thought that a minimum of 1/8-inch of Equilox should remain between the foot and the shoe. But Burns finds much less is necessary. The process becomes a lot easier and neater without having the fiberglass in the mix.
Now you are at a critical point. Remove the boot from the foot and carefully place the shoe on the foot, exactly where you want it. Next, press it down evenly and gently, using a slight, back-and-forth twisting motion to ensure even distribution of the adhesive between the foot and shoe. If you do this correctly, excess Equilox will be forced out evenly all around the shoe. Using your tongue depressor, scrape away all the excess from the perimeter of the shoe.
Burns taught me another trick. Cut one end of the tongue depressor to about 45 degrees. Using the cut end, remove excess Equilox from the inner rim of the shoe. This reduces sole pressure and makes the finished foot much more attractive.
Pay special attention to the heels. You want the adhesive to come up the heels about 3/4 inch and blend in. Do not let it reach any part of the heel that is soft and sensitive. If you do, it will irritate the heel over time, resulting in lameness and an unhappy client.
It is paramount that the horse’s foot remains elevated until the adhesive is set. Again, this is temperature dependent. If the day is cool, a heat gun can be directed at the shoe to speed up the process. As the Equilox sets up, the chemical reaction produces heat. You are just about finished when the foot is getting hot and the adhesive is getting firm. When you are confident that the adhesive is set, let the horse put its foot down. Stay with it for 5 minutes to prevent it from pawing and moving around.
Watson wrapped the foot in shrink wrap or some other plastic wrap to aid in the curing process. Burns’s method uses less adhesive, so wrapping isn’t necessary.
Burns has a method for cleaning metal shoes before gluing. He first uses a small drum sander to remove all external debris from the surface. Next, he uses a butane torch to heat the shoe and burn off any oil residue left on the surface from his hands. This extra step is especially important when using steel shoes. Once the shoe is clean, apply the Equilox and place it on the foot as quickly as possible.
In cold weather, Burns applies the adhesive onto the hoof rather than the shoe. Curing of the adhesive is accelerated by the warm shoe rather than slowed down by a cold one. Keep this tip in mind if you work on the frozen tundra. It is a good one.
Dressing And Maintenance
To finish the wall and the perimeter of the shoe, Burns starts with his rasp. If the shoe was set back from the toe, he rasps the toe back to the shoe to give it a more finished appearance. To finish the heels, he uses his Dremel tool with the duller, used point. Great care is taken to clean any excess adhesive from the heels and to blend the adhesive onto solid wall.
The rotary drum sander, powered by the cordless drill, is used for the final finish. Burns does not use hoof sealants. He feels that “clean and dry” is the best way of maintaining hoof health.
He also recommends using Magic Cushion hoof packing on horses with thin sensitive soles. He finds that soles packed with Magic Cushion exfoliate less. This creates a thicker, tougher sole. Pack the feet every other day as directed for best results.
Getting Them Off
Glue-on shoes can be left on for variable lengths of time, depending on the individual horse and situation. The usual time is 4 to 6 weeks, but for horses with compromised feet or on stall rest, 8 to 10 weeks is not uncommon.
Burns uses a “retired” pair of hoof nippers to remove glue-on shoes. He carefully cuts the adhesive at the heels to break the glue-hoof bond. Next, he applies leverage, just as he would pulling off a nailed-on shoe. Once the initial cut is made and the adhesive is separated from the wall, the shoe comes off easily.
If additional adhesive is needed to fill in gaps or areas that were not properly filled, extra Equilox can be easily added without creating problems. If only a small amount is needed, Burns will mix it in the palm of his gloved hand using a tongue depressor and apply it to the foot without having to juggle a cup. I thought this was a clever idea.
When Polyflex shoes are being used in an attempt to eliminate lameness, Burns occasionally glues the shoes on temporarily using Super Glue. This allows him to determine if the shoes will alleviate the lameness before going to the expense of gluing them on with Equilox. The trim, foot prep, and shoe shaping are the same. Next, he cuts felt material into a rim pad and glues it to the shoe with Super Glue. Finally, he saturates the felt with the Super Glue and glues the shoe to the foot as if he were using Equilox. The felt provides a flexible contact surface to bond the shoe to the foot. Without the felt, the Super Glue does not have enough viscosity to fill the gaps.
The shoes will normally stay on for 2 to 3 weeks. This is long enough to judge whether the Polyflex shoe is helping to alleviate the lameness. If the shoes seem to be helping, they can be glued on with Equilox for more permanent bonding.
In the last 2 decades, advances in farrier science have jumped forward more than in the preceding 2 centuries. As more advances in technology and science are made, more new and complex innovations will become commonplace. In the future I am sure that the nail-on shoe will be seen as antiquated as the horse-drawn plow. What we are doing now is the foundation for things to come. Challenge yourself to improve on current methods. Your idea may be the next brick in the wall.