What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Do we need to prime the piano hinges?

CubedRoot

CubedRoot

Well Known Member
I am assembling the trim tab section of my RV-7 tail kit, and I am wondering if we are supposed to prime the naked aluminum of the piano hinge that is used to attach the trim tab to the elevator E-606PP spar.

I'll be setting up a priming session in a few and want to know if I should spray this little hinge as well.
 
I don't know if "need" is the right word... But I can't think of a reason why it would hurt. It sure is not alclad so this may or may not be primed as much as any other part? But take this with a big grain of salt... You are still ahed of me. I am still on the rudder :)
 
Prime hinges

Not sure about "need" but they are exposed so I prime them.
But to put things in perspective, I also prime nutplates.:eek:
 
Good question.

This is a good question. Thanks for asking. I was worrying about the same thing. The nut plates for the wings look like they are coated.
 
Last edited:
The dull gray/blackish color you see on the nut plates is phosphate coating, A lower level of corrosion protection. It is an acceptable surface preparation if you want to apply primer. Therefore no problem in priming. Some may agree that leaving them not primed still provides adequate corrosion protection as long as they are not exposed to open climate.
 
Thanks

Nedimbek said:
The dull gray/blackish color you see on the nut plates is phosphate coating, A lower level of corrosion protection. It is an acceptable surface preparation if you want to apply primer. Therefore no problem in priming. Some may agree that leaving them not primed still provides adequate corrosion protection as long as they are not exposed to open climate.
Click to expand...
Thanks for this info. Really good to know.
 
Nedimbek said:
The dull gray/blackish color you see on the nut plates is phosphate coating, A lower level of corrosion protection. It is an acceptable surface preparation if you want to apply primer. Therefore no problem in priming. Some may agree that leaving them not primed still provides adequate corrosion protection as long as they are not exposed to open climate.
Click to expand...

Good to know. Thanks!
Do we know what kind of metal they are made out of.
 
RV7ForMe said:
Good to know. Thanks!
Do we know what kind of metal they are made out of.
Click to expand...


Commonly used nut plates are made out of carbon steel. Please remember they can come in various materials and finishes as well, such as alloy steel, stainless steel, passivated, cadmium plated, zinc plates or even with dry film lubricant coated etc. You have to look at the related NAS.
 
Nedimbek said:
Commonly used nut plates are made out of carbon steel. Please remember they can come in various materials and finishes as well, such as alloy steel, stainless steel, passivated, cadmium plated, zinc plates or even with dry film lubricant coated etc. You have to look at the related NAS.
Click to expand...

Thank you !
 
Nedimbek said:
Commonly used nut plates are made out of carbon steel. Please remember they can come in various materials and finishes as well, such as alloy steel, stainless steel, passivated, cadmium plated, zinc plates or even with dry film lubricant coated etc. You have to look at the related NAS.
Click to expand...

I'm not sure if the K-1000 series we usually use are actual Mil-Spec parts, nut they are made to similar specifications.

MATERIAL:
Carbon or alloy steel, heat treated Rc. 49 max.
FINISH:
K1000-(*) Cadmium plate per AMS-QQ-P-416, Type II, Class 2, plus Kaylube molybdenum disulfide dry film lubricant per AS5272.

So they may look 'black' but are actually cadmium plated under that dark lubricant, and if I'm reading my spec sheets correctly, these nutplates have a cad. plating that is 50% thicker than that on our AN bolts.

Again, should be good to go as-is.
 
I'm at the same build stage, and had the same question. Checked the MS. The -2P means the hinge is 5052 alloy, and is anodized so it does not require priming.

For info, any doubts about hardware can be resolved by looking up specifications on everyspec.com, where the specs can be downloaded in pdf format. A Google search on the spec number will generally take you to that site also.
 
I recommend not priming or painting the hinges.
1. They will be lubricated at least once a year, this will give all the protection you need
2. Paint often flakes off the "eyes" with time and that looks awful,
3. Too much paint, and it can cause binding of two hinge halves

A clean unpainted, lubricated hinge, looks clean and professional, (very subjective!)
 
Steinway "D"s & RV s

Steinway grand pianos and RV's generally get stored indoors away from salt spray and IMHO both look better with non primed, non painted hinges:D
 
Last edited:
You must log in or register to reply here.
Back
Top