Rotor Blade Chip Repair

[drthomasd]

I would appreciate help in understanding the process an owner can take to repair small chips in the leading edge of composite rotor blades.
Picture is of my ELA EVO rotor blade. Thanks.

 

[Sv.grainne]

I've never repaired a rotor blade but have done some props. I used thickened epoxy, West System thickened with colloidal silica.

 

[Strike]

Gradirei aiuto per comprendere il processo che un proprietario può intraprendere per riparare piccole scheggiature nel bordo anteriore delle pale del rotore in materiale composito.
L'immagine è della mia pala del rotore ELA EVO. Grazie.

Q These are the classic holes that are created when the original stucco comes off, normally it is sufficient to close them with epoxy resin if you work well you don't even need it. repaint the edge!!

 

[Aerofoam]

One looks deep, like it was over a void, I would make sure the void is not significant, then just patch with gelcoat, epoxy putty, or thickened resin.

 

[schmoe90]

One thing I've found (test with whatever you're using) is that epoxy doesn't stick to parchment paper. I've taken to clamping some over my fix, meaning less to sand off.

 

[DarDow101]

Won't be fixing these rotors.

 

[Strike]

Non ripareremo questi rotori.

ILBasically 4 REAL DEMENTS

 

[Sv.grainne]

I would appreciate help in understanding the process an owner can take to repair small chips in the leading edge of composite rotor blades.
Picture is of my ELA EVO rotor blade. Thanks.

If you probe the "chip" holes how deep are they into the blade?

 

[Aerofoam]

One thing I've found (test with whatever you're using) is that epoxy doesn't stick to parchment paper. I've taken to clamping some over my fix, meaning less to sand off.

I use premium packaging tape (Thicker) to compress over curves.
If you wrap it far enough, you can even heat shrink it to compress more.
It sometimes leaves residue, but that comes off with solvent...

 

[drthomasd]

Thanks for all your input!
The depth of the chips are all the same, approximately 1- 1.5 mm. The photography makes it look deeper I believe.
Looks like epoxy is the choice however since I am a retired dentist I thought of using light cured composite resin. I have ordered the resin, etching liquid, bonding agent and an LED curing light for just over $100. I will run some test and report back.

 

[Aerofoam]

Thanks for all your input!
The depth of the chips are all the same, approximately 1- 1.5 mm. The photography makes it look deeper I believe.
Looks like epoxy is the choice however since I am a retired dentist I thought of using light cured composite resin. I have ordered the resin, etching liquid, bonding agent and an LED curing light for just over $100. I will run some test and report back.

The UV resin should be fine, but you want to load it with something easily sanded, like phenolic, or glass microspheres. (Micro balloons)
Also, make sure it is Ok bonding to un-reacted amines, or make sure to lightly grind out the depression to expose fresh material.
A dentist drill would be perfect for this....
If you tape over the patch tightly, you probably wont need to sand, but it is better to make sure the patching material
is easier to sand than the substrate, so you don't mess up the blade if you have to shape the patch.....

 

[WaspAir]

Sounds like a second career in the making here, with all the skills and tools already in hand!

 

[j4flyer]

I have repaired many, many composite prop blades using a Jerrie Barnett fix. You mix a slurry of baking soda and super glue. You fill the chip and put wax paper over the repair and reinforce it with clamped popsicle sticks. You remove the paper after 24 hours and sand it smooth. It creates a strong bond that looks professional as well. This works on wood as well as composites. I never had a repair separate from a prop.

 

[Doug Riley]

Remember that epoxy and polyester resins have no resistance to UV damage. I've seen many hasty repairs on fiberglass done with these resins. If the patch is left unpainted, it yellows and eventually just crumbles away from UV degradation.

I've used the baking-soda-and-superglue thing. It does work, and hardens very quickly -- but I think it has the same UV problem as the other resins in the long run.

The nice thing about gelcoat is that it is UV-protected. When I contacted McCutchen about fixing blade damage of the sort show in the poster's pictures, they just sent me a can with a glob of red gelcoat in it. It worked nicely and held up perfectly. So I'd select that.

I use ordinary 2" wide clear shipping tape as a mold. Put the no-adhesive side against the wet gelcoat (i.e. sticky side up). Then stick this piece to the blade with a larger piece of the same tape over it, sticky-side down. The thicker the tape, the smoother the result (so spring for the better stuff, like 3M, and skip the store brand).

 

[Aerofoam]

The super glue also has adhesion problems with unreacted amines, so the surface should be scraped and cleaned with acetone.
It will harden immediately, but is also harder than the surrounding material, so sanding can be difficult.
Gelcoat is polyester resin and also has no UV protection except the massive loading of talc and pigment that makes it thick.
It will last a long time, but is always losing the outer layer and has about 1/10 the adhesion of epoxy.
That being said, it's chip repair which I have actually done with light weight spackle, so it doesn't need to be that strong....

 

[Sv.grainne]

I Used thickened epoxy and black spray paint

 

[drthomasd]

Reporting back that I made some trial repairs of my rotor blade chips with epoxy, dental resin material and gel coat. Vastly preferred the gel coat material due to ease of use and color matching. I purchased RAL 9003 Signal White gel coat from Fibreglast.com. Unfortunately one quart is minimum size.

 

[magknight]

I would appreciate help in understanding the process an owner can take to repair small chips in the leading edge of composite rotor blades.
Picture is of my ELA EVO rotor blade. Thanks.

I’m curious what the factory suggested. How’s their support?

 

[Abid]

I would appreciate help in understanding the process an owner can take to repair small chips in the leading edge of composite rotor blades.
Picture is of my ELA EVO rotor blade. Thanks.

I think you should contact ELA for technical support. A hole or two looks kind of deep in this picture. You can use a micrometer to measure the hollow depth. Gelcoat paint and primer should not be more than 40 thou. This seems deeper to me like it went into a void or bubble and if so that may require sanding down to determine how big or wide that is and ask ELA for proper procedure.

 

[Falco]

I have repaired many, many composite prop blades using a Jerrie Barnett fix. You mix a slurry of baking soda and super glue. You fill the chip and put wax paper over the repair and reinforce it with clamped popsicle sticks. You remove the paper after 24 hours and sand it smooth. It creates a strong bond that looks professional as well. This works on wood as well as composites. I never had a repair separate from a prop.

Im thinking this is most likely a joke. For one, if you try and mix up a slurry of super glue and baking soda you'll need a gas mask from the fumes it'll kick off. And, before you can fill the chip you'll find your slurry has turned into a hot smoking ball of goop that is harder than chinese arithmetic. Also, you'll need a grinder with 10 grit sandpaper to even scratch the surface of it. Don't believe me? Give it a try and tell us how it went. I could write a book on the highs and especially the lows on working with super glue and have everyone rolling on the floor laughing your guts out from just reading the first page! Cheers! PS. I'm still looking for a cdi for my 72 hp Mac.