Flexx® shoes

Q:  Why did Sound Horse develop & introduce the Flexx® Urethane Horseshoes?

 A:  Around 2008, the SoundHorse team started development work on non-metallic horseshoes.  We drew on the chemical, elastomer & plastics expertise of our manufacturing partners and identified several urethane chemistries suitable for the modern farrier.  After the successful introduction of our polyurethane medial / lateral extensions in Lexington, KY we were confident that these materials would allow us to introduce urethane horseshoes that met and/or exceeded the rigorous performance requirements of professional farriers.

The Flexx® horseshoes are built to allow farriers to employ the direct-glue shoeing process as an alternative to aluminum shoes. The new elastomer (polyurethane) horseshoe is dimensionally identical to conventional forged aluminum shoes and is “glue friendly” but overcomes a common direct-glue complaint of “hoof capsule restriction”.  The Flexx® shoes bio-mimic™ natural hoof movement and reduce hoof capsule restriction by allowing modest heel movement.
FAQ - Flexx® Urethane Horsehoes FAQ - Flexx® Urethane Horsehoes

Q:  Are the Flexx® horseshoes intended to replace traditional shoeing products and methods?

A:  Absolutely Not!  The Flexx® products will be one of the many “tools” the modern farrier has in his/her inventory of solutions to better serve the customers.  These urethane horseshoes are for the farrier or vet who is currently doing direct-glue application of aluminum shoes but may be looking for a lighter, less rigid option for the horse.  Sound Horse will be building our Flexx® shoes in shapes and sizes to meet the needs of the market.  We have started with 1) Medial/Lateral Extensions, 2) Therapy Shoes for young horses with a clubby / upright hoof, 3) Training Plates for pre-sale yearlings and young horses, 4) Sport Shoes, 5) Roller Motion Shoes

SoundHorse shoes are built with GRIT technology (pat.app) and grABS™ technology (pat. app).
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Q:  Aren’t all “plastics” alike?

 A:  No – no more than all farriers, all trucks or all aluminum or steel shoes are alike.  Plastic is a generic term that has been used to cover almost all types of non-metallic, chemically-derived compounds.  There are huge differences between “plastic” compounds; some of the differences are based on the chemistry and some are based on the manufacturing methods.  The most critical differences generally exhibit themselves in performance where the design & physical properties of specific materials yield widely varying results.

FAQ - Flexx® Urethane HorsehoesQ:  How can I tell the differences between these plastic shoes? 

A:  For a start, if it doesn’t look like a horseshoe, that’s a clue to how much you may or may not like its performance. If it is a lot thicker or wider than a typical metal shoe or it has a strange appearance, it is probably due to the manufacturer’s choice of the material. Most “plastics” do not possess the rigidity or durability required in regular shoeing applications. Manufacturers frequently make up for weak materials by adding physical dimensions (thickness, width, closed heels) to add strength or other properties. Superior properties that allow a more conventional shape will require a more expensive material or one that is difficult to process.

Q:  What “plastic” material does Sound Horse use to make the Flexx® horseshoes?

A:  Sound Horse uses a high temperature, thermoset, polyurethane (an elastomer) to achieve the balance of properties that farriers and vets demand in their direct-glue, non-metallic horseshoes.  Polyurethane thermosets cannot be continuously melted and reshaped into new products as can be done with thermoplastics.  High temperature pour & cure yields a material that allow our shoes to be dimensionally similar to aluminum but much lighter while delivering suitable rigidity incorporating just a bit of “flex” at the heels.  In addition, the specific family of thermoset urethanes we chose has proven to be somewhat “glue-friendly”…. A characterization voiced by all of the farriers regularly using the Flexx® products.  The new grABS™ technology (pat. app.) introduced in January 2016 overcomes all glue issues and delivers the BEST adhesive bond strength in the industry – with no shoe prep required.

Note:  Sound Horse uses a dark blue color as a company ID for our Flexx® shoes.  There may be some modest variation of the blue color when you buy them or when they are applied but, the shoes darken with exposure to UV (sunlight).  This does not affect the material, it just darkens.  Either way, in less than a week outside or on the hoof they will turn black.

FAQ - Flexx® Urethane HorsehoesQ:  How do I shape the Flexx® horsehoes?

A:  You can shape Flexx® by hand if all you are doing is opening or turning a branch. If you want to do more work, use a hammer and anvil or a stall jack as you would for forged aluminum shoes. The polyurethane elastomers we use are rugged and will not break or fracture. We strongly advise that you not use heat to shape ANY urethane horseshoes. Heat will significantly degrade the properties and, if the temperature is high enough, can generate a noxious gas.

Q:  What application method does Sound Horse recommend?

A: Each farrier / vet using a direct-glue application of horseshoes has their own, proven, trusted method which they should continue to use.  Sound Horse does recommend the use of Acrylic Adhesives when applying the Flexx® horseshoes. This is because all of our user experience has been with acrylics (generally “fast sets”). We are now advised that some farriers have used Vettec adhesives.

Q: Can I use nails to apply the Flexx® horseshoes?

A:  Sound Horse does not recommend the use of nails to apply the Flexx®  horseshoes.  While there is a crease, the urethane material will not grip & lock the nail heads as would metal.  Acrylic adhesive (fast set) is generally the accepted method for successful application.  We have, however, heard of some farriers “pecking” a nail in to “guarantee” the attachment.  Most shoeing applications will not need this mechanical fastener.

FAQ - Flexx® Urethane HorsehoesQ:  Can I drill & tap the Flexx® shoes for studs?  Can I use drive-in studs?

A:  The urethane elastomer we use can be drilled and tapped for studs.  You can also use the drive-in type small, tapered studs (Mustad or Kerckhaert).  The encapsulated “stiffener” wire stops at the end of the crease in the SPORT shoe to permit a farrier to drill and tap the shoe for studs.

All of the Flexx®  shoes can be fitted with drive in studs.  Neither the screw-in nor the drive in studs will lock quite as tightly as they would in metal shoes.  The friction fit generated by typical metal-to-metal surface interference is somewhat lower in a urethane shoe.  The Sound Horse shoes will, however, generate adequate locking for most typical stud applications.

Q:  Don’t “plastic” horseshoes wear out faster than metal?

A:  Good question – it depends on the plastic. Many manufacturers will use a thicker section of “plastic” to accommodate the wear problem so the shoes will last through the normal shoeing interval. Flexx® horseshoes use a high temperature, thermoset urethane (an elastomer) to keep the shoe dimensions close to those of forged aluminum and we ADD an abrasive material to deliver improved wear performance. By use of a proprietary process with GRIT (pat. app.) Sound Horse is able to concentrate the abrasives toward the bottom of the shoe to deliver maximum wear performance for the user.

Q: What about grip or traction?  I heard that “plastic” horseshoes are slick and don’t grip the ground very well.

A:  Again – good question. Sound Horse does a couple of things differently. 1) All Flexx® shoes are built with a crease. This design feature aids grip because the crease enhances traction. 2) Our Flexx® shoe design uses the same dimensions as a forged aluminum shoe – with a crease. This means a higher unit loading at the ground surface for maximum grip potential. 3) The addition of the hard abrasive GRIT  material to the shoe and concentrating it at the ground surface delivers a significant improvement in traction as the urethane (plastic) material slowly wears from the shoe ground surface (pat. app.).

Q:  Do the Flexx® shoes reduce shock better than the metal shoes?

A:   The urethane elastomer used for the Sound Horse shoes is certainly a better material for shock attenuation than direct-glued aluminum and steel horseshoes. For real shock-reduction performance for the seriously sore hoof you might want to look at the Sound Horse Series I shoes with the built in ¼-inch thick, urethane rim pads. For direct-glue applications, however, the Flexx® shoe’s urethane material and design allow the hoof to “flex” and move a bit at the heels to bio-mimic™ nature. This modest lateral/medial movement with some heel freedom in the vertical axis means the hoof capsule can move more like an unshod hoof. Nature designed the horse’s suspensory system; man domesticated the horse & built metal shoes to protect the hoof & farriers have invented methods to attach shoes to the hoof. Sound Horse designed Flexx® to optimize shoes for the direct-glue practitioners.

Q:  Plastic, Elastomer, Thermoset, Thermo-plastic…… interchangeable terms?  What’s the big difference?

A:  Many plastic materials (polyethylene, polypropylene, etc.) are typically not as durable or as rugged as elastomers like polyurethane. Many common plastic materials start life as polymerized thermoplastics and are then ground or chopped into pellets that facilitate their use in injection molding processes. Each time these pellets are heated and processed adds to the “heat history or aging” of the material….. the more times you heat it; the more physical properties you tend to give up. Also, most injection molders will reprocess scrap and use a percentage of recyle in any production run (adding more to the heat history) further reducing the performance potential of the material. Sound Horse polyurethane is a thermoset that cannot be continuously melted and reshaped into new products as can be done with thermoplastics. It delivers superior performance when compared the thermoplastics..

High temperature thermosets generate better properties than room temperature thermosets.  Polyurethane (urethane) is an elastomer that can be produced in both modes (room temp. or high temp.).  Much like steel, higher production temperature yield better materials.  High production temperatures allow the cross-linking and polymerization of urethanes to proceed in a way that generates tighter & stronger molecular bonds.  Room temperature cures tend to be used for cosmetic products, such as props or models with limited functionality.  Both types of urethanes are chemically similar but the products generated are dramatically different.  Sound Horse Flexx® horseshoes are all built in ourPolymer Forge™ using high temperature production processes and elastomer thermoset polyurethanes cured for at least 16 hours at 200°+ Fahrenheit.

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