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Hot Air Balloon Envelope Fabric Recoating

Depending on the condition of the fabric in your balloon envelope, you may want to consider envelope recoating as the most cost-effective way to keep your balloon in the air. If the fabric still has reasonably high tensile strength (5-10 pounds or more above factory minimums) and adequate tear strength, but is very porous, it may be a perfect candidate for recoating using an FAA-approved process that we've had excellent results with.

This recoating process, called Koala-Coat #25, will bring back zero porosity to your fabric, and in many cases will actually increase the tear strength of the base fabric. It is radically different than the older urethane or acrylic recoating solvents that tended to disagree with the fabric in many ways, and often resulted in a big, sticky mess of weak fabric at the end.

The new Koala-Coat process is a real miracle worker certified on all types of balloon fabrics - Nylon 6, 6.6, and Polyester. The new coating will no doubt outlast the balloon's base fabric, so the more remaining strength in the fabric, the longer your balloon will last after recoating. Although a specific guarantee of flight hours after recoating cannot be made for that reason, we don't recommend recoating unless we're sure it will guarantee significant long-term results for your envelope.

Keep in mind that the new coating will want to bond strongly to the base fabric - if the original coating is still quite firmly attached, the new coating won't bond as effectively to the fabric. This is important to consider, since balloons with original coatings that are still largely intact are not necessarily very good candidates for a recoating job. To look at it a different way, they aren't porous enough to consider recoating yet. However, one balloon manufacturer has made it a practice to apply coating to the outside of some brand new balloon envelopes even when the original coating is still brand new on the inside.

Although not all old balloons are candidates for recoating, there are a couple key items to look out for when trying to determine the practicality of an envelope recoating job. If the original coating is beginning to flake off or is already worn off, and the fabric tensile and tear strength values remain relatively strong, there's a very good chance you will be able to apply coating to the envelope and come out with extremely positive results. Your balloon will no doubt once again fly like it did when new.

How It's Done:

  • The first half of the Koala-Coat process is a special fabric wash which will help remove most of the remaining original coating, plus any dirt and debris, as well as prime the base fabric for the new coating. This fabric wash is lightly sponged onto the fabric.
  • The second half of the process is the actual recoating step, where the new coating is applied evenly with sponges to make sure it penetrates deeply into the base fabric. The new coating is applied to the entire top two thirds of the envelope, where zero-porosity is most important.
  • When the coating is dried to the touch in a few minutes, the process is basically finished. The coating will need to cure overnight, after which you'll be able to fly!

Success Stories:

• Barry DiLibero, who pioneered the development of Koala-Coat, regularly flies his 1994 Cameron A-105 recoating testbed, "Larry The Phoenix." The original DuraFlight fabric underneath the Hyperlast top 1/3 grew porous in the first two hundred hours of flight, but a Koala-Coat application around the equator saved this balloon from early retirement or massive fabric replacement. It continues to fly like new, with over 275 hours since recoating!

• Jon Radowski's 450-hour 1987 Aerostar S60A (105), "Skidmarks," had been growing extremely porous in the royal blue top cap, although the coating in all colors of the rest of the envelope still remains intact. A recent hour-long morning flight had consumed 24 gallons of propane carrying pilot plus one average passenger. A three-hour session late at night sealed the Spring Top back to its original nonporous state, and the balloon flew the next evening with great results. The hour-long afternoon flight directly after the coating consumed only 17 gallons with pilot plus three average passengers aboard.
• Fred B. Rabbit, a 1990 FireFly 8B, was getting extremely porous in the top half. Owner Keith Sproul recoated the top half of the envelope including the ears. What was once a saggy balloon again flew just like new!

• Jon Radowski's 295-hour 1987 Aerostar S60A (105), "Daydream Believer," was purchased with excessive porosity but good fabric strength. With 120+CFM in most colors in the upper half, it was way past the maximum porosity allowable for even a 50-hour annual inspection (50-70CFM). The fabric strength was still well above the minimum requirements, but the porous fabric meant the envelope would not pass an annual inspection at all. The parachute and top 1/3 was recoated with the usual results (0 CFM), and the envelope was returned to service. It now has nearly 350 hours and shows no signs of porosity in the recoated section. The equator now needs to be recoated, since that's the only place the air is able to find a way out!

Stay tuned for other success stories as we obtain permission to publish their information.

 

 


All content and images ©2000-2012 Jon Radowski unless otherwise noted. All rights reserved.