Rivet count

So before buying my RV-10, I spent 20 years flying airplanes that we almost totally devoid of rivets. I have brought up the subject at the local coffee urn as to why we spend years drilling, counter-sinking, de-burring and driving rivets when there are literally thousands of almost 50 year old Grummans flying around that are glued together.

If it would save hundreds of hours in construction time, why not reduce the rivet count by 80% and bond things together?

Some say that it would be impossible to bond joints in the EAB garage but many of us do so successfully in our fuel tanks.

Thoughts?

Do they...

Do they ever talk about the ones that aren't still together?

I learned to fly in a AA-1B and loved it...

rocketman1988 said:

Do they ever talk about the ones that aren't still together?

I learned to fly in a AA-1B and loved it...

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I just got the eye roll from across the room for laughing at my laptop

I know of no Grumman that was lost to delamination. It is easy to detect and usually due to corrosion. The repair is to rivet the piece on 1? centers with wet proseal.

Not lost...

Not aircraft that were lost in flight but aircraft that were no longer airworthy due to delamination.

Some time back, I was looking to purchase a AA-1B, or any of the others cats. I looked at quite a few and found many that had issues...they may very well have been repairable but I just wasn't into a project...

rocketman1988 said:

Not aircraft that were lost in flight but aircraft that were no longer airworthy due to delamination.

Some time back, I was looking to purchase a AA-1B, or any of the others cats. I looked at quite a few and found many that had issues...they may very well have been repairable but I just wasn't into a project...

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Not surprising that you can find a lot of 40-50 year old airframes that are suffering corrosion issues whether bonded or riveted. You can take the plane out of Florida but you cannot take Florida out of the plane.

The only other issue is that they cannot be paint stripped with methylene chloride based stripper as the fumes can delaminate the bonds. I hate the stuff on any airframe. It has to be totally neutralized or it will eat the aluminum lap joints too.

It's not a trivial matter to prepare aluminum for a reliable bond. I'm sure that others are more knowledgeable than I am about that.

Some folks might remember that I'm bonding and riveting my RV-3B together. I'm using the bond primarily for two purposes: as a liquid shim and as an assembly fixture, replacing clecoes. I am not relying on it for primary structure.

Figured I'd better mention that before someone draws the wrong conclusions.

Dave

David Paule said:

It's not a trivial matter to prepare aluminum for a reliable bond. I'm sure that others are more knowledgeable than I am about that.

Some folks might remember that I'm bonding and riveting my RV-3B together. I'm using the bond primarily for two purposes: as a liquid shim and as an assembly fixture, replacing clecoes. I am not relying on it for primary structure.

Figured I'd better mention that before someone draws the wrong conclusions.

Dave

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Dave,
Exactly my point, if there was a chemical and mechanical bond, could the rivet count be cut in half and save a ton of time? Or is the bonding that time consuming? I am a flyer, not a builder.

MConner said:

Dave,
Exactly my point, if there was a chemical and mechanical bond, could the rivet count be cut in half and save a ton of time? Or is the bonding that time consuming? I am a flyer, not a builder.

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The question is whether 10,000 amateurs could get reliable structural bonds, and if the bonds are/were defective, how would those same amateurs know it?

Rivets are easy to inspect visually. Glue joints? I have no idea how you verify the quality of the joint, other than indirectly, which would be by very closely following a good known procedure and running test coupons on the glue and process used for each joint.

Riveting is fast and fun

MConner said:

...Exactly my point, if there was a chemical and mechanical bond, could the rivet count be cut in half and save a ton of time? Or is the bonding that time consuming? I am a flyer, not a builder.

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I personally find riveting fast and fun. Sure, there are some rivets that are not easy to squeeze, sometimes I needed 3 hands to drive a rivet or two, and I've had my share of drilling out bad rivets but overall that feeling of putting two pieces of metal together "permanently" after often many hours of prep is extremely satisfying.

+1 on that. Riveting is the dessert of aluminum aircraft building

MConner said:

Dave,
Exactly my point, if there was a chemical and mechanical bond, could the rivet count be cut in half and save a ton of time? Or is the bonding that time consuming? I am a flyer, not a builder.

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It could be cut in more than half. Bonding is adequately strong, according to the pull samples. You'd still need rivets in a few places, though.

It's very slow, even in the crude form I'm doing it. If I were to follow some process for a more-secure bond, it would take longer and require other equipment and environmental controls. I don't know much about that, merely that it's both possible and something not in my plans.

To repeat, it's very time consuming.

Riveting has some very useful attributes that bonding doesn't have:

It's easy to inspect,
It's easy to replace a badly-done one,
A single bad one usually doesn't jeopardize the joint,
it's reliable,
It's tested and known,
The tools, processes and parts are cheap and readily available.

Go rivets!

I'm all for riveting. And I've seen one RV-3B (I go out of my way to see RV-3Bs since I'm building one) that is every bit as smooth and slick as the best bonded one I've seen. So it can be done.

Dave

What I have seen..

For what its worth,
In my almost 40 years of Heavy aircraft maintenance, I have seen both types of construction and what it takes to MFG and repair both. Anyone whom ever worked on the Fokker F-28 series of jets can attest. The stringers are glued to the wing skins, and fuselage skins with just a few fasteners at the ends. The process is extremely controlled ( I went to the factory) and not the type work you would do in a garage. Most all bonding is performed in an autoclave or under heat/vacuum bagging, not to mention the chemical pre-assembly process needed for adhesion. Fokker didn't even approve post-production re-bonding, and all repairs are done via mechanical fastening (rivets). At my day job, we build metal bonded skin assemblies, and all work is done in controlled clean rooms with equipment I cant afford, and we have to perform pull tests on test coupons ect...I have a love of riveted joints for inspectability , and don't like the mystic of trust in glued joints !