Rain will reduce the life of PROP GUARD as the constant impact of the water droplets will eventually fatigue the material, causing it to become more brittle with progressively less ability to absorb energy. This constant water hammering will eventually cause it to shred, starting at the prop tip area. This is a harmless situation that causes no concern in flight, but it will require repairing the PROP GUARD installation. PROP GUARD will tolerate a considerable amount of light rain, but fails fairly quickly in heavy rain. When PROP GUARD is failed by rain, it has already sacrificed itself to prevent considerable propeller erosion.

No, PROP GUARD is an FAA-PMA/STC product, but the STC specifically states that a form 337 is not required. It does require an A&P mechanic endorsement for return to service.

Although PROP GUARD has been successfully used by some customers on non-certified aircraft with composite propellers, it is not FAA approved yet for applications not listed on the FAA Approved Model List.

Yes, it will bond well if care is taken to remove all traces of wax or silicone with a commercial wax and silicone remover or Naphtha using several clean paper towels.

The problem is most likely caused by silicone contamination. Any trace of silicone compounds will act as a release agent and destroy the bond of the underlying paint or PROP GUARD adhesive. Silicone cannot be removed with lacquer thinner, MEK or other standard solvents. Naphtha or a silicone remover found at local auto parts or paint stores is required to remove it. Just repainting and reinstalling will probably not solve the problem. The silicone contamination can come from something as simple as touching the prop with your hands that have touched RTV or a waxed surface.

High quality spray can paint has worked well when the prop has been cleaned and the metal primed effectively.

PROP GUARD is not certified for use on certificated wooden propellers. It can sometimes be used on non-certified aircraft applications. Some varnish used on wooden propellers is not compatible with the PROP GUARD adhesive and the bond will fail. PROP GUARD has been successfully used with many varnishes. We recommend testing by placing a small sample of PROP GUARD on a surface with the same varnish before installing on a propeller.

PROP GUARD will stop water erosion of the propeller and has been used on seaplane applications. However, it has very limited life on high speed propellers that are subject to a lot of water spray. Water spray will reduce the life of PROP GUARD as the constant impact of the water droplets will eventually fatigue the material causing it to become more brittle with progressively less ability to absorb energy. This constant water hammering will eventually cause it to shred, starting at the prop tip area. This is a harmless situation that causes no concern in flight, but it will require repairing the PROP GUARD installation. Some seaplane operators use PROP GUARD knowing that they will have to frequently replace PROP GUARD at the prop tip area. By sacrificing itself, the PROP GUARD has stopped considerable prop erosion. PROP GUARD will hold up relatively well on lower horsepower applications where the propeller has good water clearance.

The special heat treated elastomer in PROP GUARD absorbs the impact energy from the particle strike. In other words, PROP GUARD gives a little and spreads the energy when something hits it.

Follow the guidance of the aircraft or propeller manufacture. When no guidance is available, conversion coating such as Alodine followed by a light coat of corrosion preventing primer followed by the finish coat has proven effective. Before you start, be sure the metal is clean and use a silicone removing compound such as Naphtha or a commercial wax and silicone remover with multiple clean paper towels to assure all traces of silicones have been removed. Most solvents will not remove silicone compounds.

There is no loss of performance for the listed applicable model propellers. We have seen some performance degradation on exotic high performance experimental applications where extreme prop speeds or extra wide propeller blades were involved. We have also seen some experimental use of PROP GUARD where there were performance increases when the PROP GUARD edge was pinked on the face (forward side) of the propeller. The zig-zag pattern of the pinked edge produces a vortices generation that helps hold the moving air to the propeller surface longer.

There is a certain size rock that will break through the PROP GUARD and damage the propeller. When this happens, the damage to the propeller will be much less than if PROP GUARD had not been there, as much of the rock’s energy is absorbed by failing the PROP GUARD.

The first installation takes longer, with reading the instructions and carefully going through each step. You always want to properly dress the propeller before you install PROP GUARD as this is the last time you will need to dress or paint the prop until PROP GUARD is replaced. First time installation on a properly dressed and painted prop takes close to an hour, and about fifteen minutes once you have done several.

Being clear allows you to see through PROP GUARD to inspect the propeller.

A flat finish material was tried but the manufacturing process to get a flat finish reduced the strength of the product. The glossy finish has little effect on light reflection in flight.

PROP GUARD is a very special high strength product manufactured to take the high centrifugal forces of the rotating propeller while being able to absorb impact energy. It goes through special heat treatments and careful quality controls. Only some of the material manufactured will pass our rigid quality standards. PROP GUARD is different.