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Old bolts -- is this corrosion?

A

Alex

Well Known Member
I'm just getting back to an RV-12 empennage kit that I started in 2010 and had to box up in 2012 due to life getting in the way. Unpacked these bolts (still in the paper bags) for the next build step, and saw what appears to be surface damage. Since it's been so long since I was last working on the plane I can't recall what condition the bolts were in when I received them.

First, let me be clear that I'm planning to order replacements for these bolts. Cheap piece of mind.

However, I'd like some advice on:

1) What are the limits for acceptability in hardware condition. Are scratches and chipping of the plating acceptable?

2) Does the marking on these bolts indicate corrosion?

and more fundamentally,

3) Do I need to be concerned about all the other fasteners in my kit, beyond typical inspection prior to installation, including rivets already installed? I'm hoping not.

Thanks,
Alex







 
They look like "bag marks" to me. Bolts packaged together bounce around in shipping and handling and leave these kinds of marks. Some of the bolts look like they where trial fitted.
There is a spec for thickness of CAD plating to meet mil spec, but I don't know of any limits for this type of surface damage. Perhaps somebody else does.
 
mike newall said:
Those bolts have been in and out but are still acceptable to me.

Move on.... :D
Click to expand...

That. However, if they have been installed, which some of these clearly have been (others just knocking around in the bag), then put back into inventory, how do you know they weren't over torqued or otherwise abused. It is just an inventory control problem; pre-assembly hardware vs. final assembly hardware.

You're doing well to simply solve your own piece of mind. If you were really certain that you had never put those bolts in a hole... That is a different conversation.
 
Cadmium

Cadmium is normally a dull silver color. The gold color is dichromate, a separate process after the cad plating. Scratches or nicks in the dichromate are not an issue.
I would replace the bolts that have a mark all the way around. In that area the cadmium is probably gone.
Cadmium is a sacrificial coating, in theory a small part will not rust until all the cadmium is gone.
 
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