Riveting Anodized Aluminium 1

[drawoh]

I am about to specify solid rivets on a black anodized aluminium sheet part. There is very little stress on this, but it should look good and I do not want corrosion. Can I have this thing riveted and then anodized, or should I have the rivet installed afterwards, and specify a relatively non-corrosive aluminium grade for the rivet?

My application is not absolutely critical at the moment, but I may have something similar later that will be critical. I would appreciate any tips, or a pointer to some literature or a website.

Thank yo very much.

JHG

 

[israelkk]

In the aerospace business they usually using an clad aluminum sheets (the alloy is covered with a thin layer of pure aluminum) If you drill the anodized parts you will have bare aluminum alloy in the holes. In the aerospace business they dip the rivets in paint primer that contain zinc before the riveting process and then apply paint all over the sheet and the rivets.

If I am not wrong, anodizing after riveting may cause some of the anodizing compounds (acids etc.) to be trapped between the rivets and the sheet and may promote future corrosion.

 

[COKA]

Hi,
In my company, we drill the holes for for the rivets, anodize the hole and around the hole and then install the rivets. Usually, the rivets are a finished product, which meand that they are already protected. I don't have experience with the black aluminum sheet, but I don't see how it would matter.

Coka

 

[MadMango]

Here at where I am we are using 6061-T6 sheet with thru holes. The entire material is hard anodized black (AMS-A-8625, Type III, Class 2), and anodized rivets are installed. We subject these to 100hr salt-spray tests with good results.

Ray Reynolds
"There is no reason anyone would want a computer in their home."
Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977
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[israelkk]

MadMango:

If I am not wrong MIL-A-8625, Type III, Class 2 used to ask for 336 hr salt-spray tests. Is there any change in AMS-A-8625 which replaced MIL-A-8625?

 

[MadMango]

[blue]israelkk[/blue], not that I am aware of. The 100hr test is strictly internal to my company, so AMS-A-8625 exceeds our requirements.

Ray Reynolds
"There is no reason anyone would want a computer in their home."
Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977
Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[rd400guy]

COKA has the solution. Definitely drill the holes for the rivets and then anodize the sheet. I'm also agreeing with MadMango to use anodized rivets. If you're primarily concerned with aesthetics, I think this will give you a very good looking part, with the corrosion resistance you desire.

 

[drawoh]

Thank you very much everyone. So this means that anodized aluminium rivets are an off-the-sheft part that I can call up on my drawing?

JHG

 

[COKA]

yes.

I omitted a very important word in my previous answer. What I ment to say is anodize TOUCH-UP, which is different from the anodizing process. You have an anodized aluminum sheet, which means that the surface configuration was changed. The anodize touch-up is applied with a brush, and there is no surface configuration change. The anodizing process is better then the touch-up, more durable, deeper corrosion protection, but the touch-up method is also widely used. If you want to anodize your aluminum sheet, you would have to strip the original anodizing, drill the holes, and re-anodize the plate. It all depends on the application of your plate, but usually the touch-up is enough.

Coka