Loctite

[David Z]

Would there be a problem with using blue Loctite?
I'm thinking more of preventing the bolt and nut from seizing together than thread locking. Although it would be a good backup.

[L.Adamson]

I haven't found a problem of seizing.......but just so you know,keep Loctite away from the canopy. It will create crazing marks.

L.Adamson --- RV6A

[David Z]

So I used the blue Loctite on the four bolts that hold the elevator hinge on the rear HS spar. I also plan on using it for the rest of the airplane. Is it redundant? Most likely yes. Is it going to cause any harm? I really don't think so.
I will keep the canopy in mind though.

[Flying Scotsman]

What is this buying you?

Properly torqued Nylocks or steel locknuts will not loosen...the engineers designed the structure to use the correct bolts for the flight loads. Same for castellated nuts.

Loctite is not an anti-seize, either.

I'm not an A&P, but I'd say use what the plans call for, and follow best practices (AC 43.13), and avoid untried "solutions".

Torque correctly, mark with Torque-seal, and move on.

ETA: From the description of Blue Loctite:

"The product cures when confined in the absence of air between close fitting metal surfaces." (N.B. Metal, not metal and nylon)
"Not Recommended For
Use on plastic parts, particularly thermoplastic materials where stress cracking of the plastic could result ."

I don't know if Nylon counts as plastic, but I'd avoid mixing the two. Who knows what Blue Loctite will do in the long term to the nylon inserts?

[pierre smith]

...really overkill. No certified airplanes that I know of use Loctite on control surface attachments...the bolts and nuts are designed to be dependable.

Best,

[carguy614]

Just a little piece of info I have on that issue. Jaguar cars uses a lot of AN hardware on their older vehicles, including nylock nuts on some of their brake attachment bracket points. They caution against using a combination of Chemical thread lockers of any kind on attach point using Nylock nuts, as it will degrade the nylon locking band pressed into the fastener. I know of no reference to this from any aviation literature, but that surely doesn't mean it doesn't exist.
Refer to "aircraft standard practice" publication to answer any questions you might have concerning fastener use. Tried and true procedure is the way to go.
Believe me, you won't experience a loose properly torqued and properly installed nylock bolt nut combination.
As for corrosion, inspect and replace affected hardware at annual if you are concerned.
Cad plated AN hardware is pretty well protected against corrosion, as you will see as your aircraft ages.
Resist the urge to substitute stainless hardware if it is not called out on the plan. If you do choose to use it in a particular location, consult the ASP publication for proper substitutions, and seek advice from Vans. The Stainless tensile strength is usually less for the corrosion resistant hardware. This is particularly important if the said bolt is in shear.

Regards,
Chris

[David Z]

I talked to Vans this morning, and they said they have never heard of Loctite hurting nyloc nuts. They also said it is a waste of time because the nuts and bolts won't corrode, seize or lossen.