Shoe Failures

Uh-oh …. A shoe came off.  What happened?

Let’s admit it, a SoundHorse shoe occasionally comes off. There are a number of reasons shoes can come off. One of them is by design and the others generally involve a mistake. Let’s review the product & processes:

  1. Horse pulls or “grabs” a shoe. When this happens something has got to give; if nothing moves there will be a catastrophic hoof wall failure. With a nailed-on shoe, the clinched nails are stronger than the hoof wall so the nails rip through the hoof wall as the shoe is pulled. If you are lucky, the shoe leaves quickly and the sole does not get stuck with a nail. Whatever happens, at minimum you probably have some broken hoof to repair.

The Sound Horse system is different.  The shoe is designed and built to separate safely from the hoof if there is a pull or grab. The cuff is securely bonded to the hoof wall and will stay attached to the hoof wall reinforcing it during & after the grab. The cuff design has the fabric embedded in the urethane rim pad – when grabbed, the fabric will start to pull out of the urethane. If the pull or grab is severe enough, the shoe will bend and then separate from the fabric cuff. No nails to stick your horse and the hoof wall is protected by the adhesive reinforced fabric cuff.

  1. The entire shoe came off the hoof.  The whole thing came off and it looks like a slipper. The fabric cuff and adhesive are completely hard and kept their shape, but the horse just stepped out of it. What happened?
    This type of failure occasionally happens.  We can generally trace the problem to one of these areas:

    • Hoof Preparation
    • Adhesive Preparation
    • Adhesive Application   
    • Shoe Application & “Dry Joints”
    • Adhesive Cure
    • Stretch Wrapping

a) Hoof Preparation: Start with a dry hoof.  You do NOT need to use solvents to clean and prepare the hoof. Once the hoof has been trimmed you should rasp the hoof wall to clean it. As a final step, use either a clean rasp or a clean piece of sandpaper to dress the outer hoof wall… it does not need to be roughened but it does need to be reasonably clean. This is good enough for all but the worst hoof problems. Don’t touch the hoof wall with your hand once this preparation process is complete.

b) Adhesive Preparation:  Mixing the adhesive COMPLETELY is very important.  The EquAcrylic ™ adhesive we supply is a modified epoxy-methacrylate. It is similar to Equilox, Equibond and several other acrylic adhesives In acrylic adhesives the hardener is very tacky and must be mixed completely to be effective. When using our EquAcrylic ™ “Twin-Packs” we recommend starting the mix in the poly twin-pack and completing it in the supplied cup. Mix in the cup for 1-minute — 60 full seconds. This will assure predictable performance.
— [do NOT use urethane repair adhesives to apply the SoundHorse shoes – they set very fast and will not work].

c) Adhesive Application: The first step is to take a small quantity of mixed adhesive & smear it on the hoof wall to allow the adhesive to start to “grab” the hoof. This is an important part of the process and will increase the reliability of the cuff attachment. Completely impregnate both of the cuff layers with the rest of the adhesive.

d) Shoe Application:  Pick up the foot and smooth the cuff onto the hoof while aligning the shoe. Use the wooden blades (supplied) to smooth the cuff eliminating gaps or bubbles and to ensure complete contact to hoof.

Dry Joints:  The epoxy-methacrylate adhesive is a very reliable material that has been in use in the equine industry for over 20 years. You must completely saturate the cuff with adhesive (also between the layers of fabric); if you don’t, you get a “dry joint”.
SoundHorse supplies a foil pack of adhesive to customers who want our “glue”. The foil pack contains 2 inner packets of 3 ounces each. We use this foil pack to guarantee fresh material and adequate quantity to do the job (for all sizes). The 3 ounces for each shoe is plenty for size 00 thru size 3. Farriers using their own acrylic glue should be aware that a 2 ounce single use jar of adhesive is adequate for shoes up to size 1 (Medium or a #7 race plate). For larger sizes you should consider using more adhesive to avoid risking a “dry joint”.
We sometimes see farriers working so very hard to make a perfectly smooth cuff that they strip most of the adhesive out of the joint between the fabric and hoof wall creating a “dry joint”. If you have a shoe drop off and it looks like a slipper with a hard cuff, you may have a dry joint issue. Relax when you put the next shoe on, the adhesive will hold it and a little work will make it look good.

e) Stretch Wrapping:  This is the critical process.  Practice by lifting a hoof and wrapping without the shoe. Wrap from high over the heel bulbs across the toe of the shoe – 5 wraps. Align the heels and continue wrapping high over the coronary band back over the heels f the shoe – 5 wraps. Repeat toe – 5 wraps. Repeat heels – 5 wraps. Wrap around entire shoe- 5 wraps. Drop the hoof. When doing this step you are stretching the wrap ~ 15-20% and securing the shoe with this “X” wrap [don’t just wind wrap around the hoof]. The stretch wrap will:

      • Secure the shoe while the adhesive cures
      • Smooth the surface of the adhesive
      • Hold heat in to accelerate cure
      • Keep the farrier & horse happy [since the hoof is not off the ground for more than 60-90 seconds]

f) Adhesive Cure: The epoxy-methacrylate is designed to cure in 5-7 minutes at 70ºF. If the temperature is lower it will take longer; hotter weather means faster cure times. At 35-40ºF expect the cure time to increase to 9-13 minutes. At 90+ºF expect the cure time to drop to 4-6 minutes. The stretch-wrap will hold in the heat and help accelerate the “cure” process. In extremely cold weather you can carefully use a heat gun to help to start the cure process. A little heat is all it takes – use too much heat & the stretch wrap will soften & slip.Open Time: This is the time that the adhesive is “open & workable” and before it stiffens up and begins to cure. You can extend or shorten this “open” time to help you with your application. We package the adhesive in “poly-packs” so you can easily cool or warm them. In HOT WEATHER put the sealed inner poly-pack in cold water as you are preparing the hoof and you can extend your working time by 60-90 seconds. In COLD WEATHER warm the adhesive inner poly pack and you’ll shorten the open time by up to 90+ seconds.

g) Adhesive Storage: SoundHorse adhesives are supplied in a sealed foil pack with two inner poly-packs to ensure a long shelf life. HEAT is the enemy of any acrylic adhesive…… heat will reduce the shelf life and significantly change the working time & characteristics of the material. We suggest that you store your acrylics in a cool place. Experienced farriers using acrylics in hot weather will carry a small cooler to store their adhesive materials (they’ll do the same in the winter). Remember, the sealed cab &/or cap on your truck can reach temperatures of 134-150 degrees Fahrenheit on a hot day. Temperatures like this will cook urethanes & acrylics.

  1. The metal shoe separated from the cuff. The shoe just dropped off the bottom and the cuff and blue urethane rim pad is still attached to the hoof. What happened? This type of failure rarely happens. We can generally trace the problem to one of two areas:
    Factory Failure      Farrier Enthusiasm

a) Factory Failure: We have infrequently had an inexplicable metal-bond failure (urethane separates from the metal shoe). The incidence rate of these is so small since 2005 as to be statistically insignificant. Our fault.

b) Farrier Enthusiasm: Sometimes a farrier enthusiastically uses a grinder to roll the toe, relieve the heel, dress the edges, etc. Energetic work with the grinder can generate LOTS of HEAT. If you cannot hold your thumb on the area that you are grinding (~130°F) then the shoe is getting too hot. These shoes are made to be “cold worked” — overheat them and you may compromise the metal-to-urethane bond. Easy does it with your grinder!!