SS Screws

[johnfurey]

I would like to use SS screws on the fuel tank but many I find don't have the shear rating of the 509-8R8 that Vans uses. What are you guys using?

[SvingenB]

When SS is combined with aluminium, the alu will corrode while SS stays fine. In my opinion it is better let the screws corrode and replace them, than to replace your tank.

[rzbill]

+1 for plated AN hardware on the tank.

SS is, as a rule, not as strong as non-stainless alloys and also not as close to Al on the galvanic scale as CAD plated.

EDIT **** Tensile strength of CAD plated MS24694S5 is 125,000 psi, the Stainless MS24694C5 is 85,000 psi or 68% ****

[Daniel S.]

Stainless structural #8 screws (MS24694C5).

[6 Gun]

When you install SS screws Dip the threads in zinc chromate paint and install . Bob

[dmaib]

Five years ago, I had installed my tanks with SS Torx screws during the build. Prior to finishing, there were some threads about SS screws on the tanks on this forum, or perhaps Matronics. IIRC, Van's suggested strongly that SS screws should not be used on the tanks since they are structural. I removed all of mine and installed the screws called for in the plans.
I learned several lessons about making those kinds of changes without really knowing what I was doing during the build.

[petersb]

I flew 1600 hours in my RV6 with stainless screws holding the tanks on.

The plane was painted for half that time, so they where not in direct contact with the aluminum for half that time.

Light aerobatics up to 4 g, nothing broke, did not see any corrosion issues.

They do tend to gaul and cause problems when removed, I will be lubricating the threads on my new RV7, Iwill be using stainless