Metal Bonding Adhesive vs Rivets

Schwemmer · #1 03-01-2012, 10:09 PM

I attended a radio control club meeting the other night and the topic was a model of the RV 4. The speaker mentioned that the first kits had the metal skins "bonded" instead of using rivets. I do know that there are bonding agents and some airplanes use that instead of rivets. Would it be possible to use bonding adhesives instead of rivets on the RV7? would it make the overall gross weight lighter? Has anyone researched this?

Thank you,
Rick

rockwoodrv9 · #2 03-01-2012, 10:15 PM

This is interesting. When I told my glass man I was building a plane and using pounded rivets, he asked me if I was going to use adhesive. I didn't even know that was an option. I asked Vans and they said it wasn't needed. Using adhesives instead of rivets didn't cross my mind. On the weight difference, I can't imagine anything being lighter than rivets. Glue or epoxy is pretty heavy. IF if worked, the benefit possibly could be less drag? From what I have been reading about Vans RV 1, it looks like they used rivets on that plane.

Snowflake · #3 03-01-2012, 10:39 PM

Just to clarify, the speaker was referring to the first kits of the model, not the first kits of the RV-4. No RV-4's have been built with adhesives instead of rivets, to my knowledge.

az_gila · #4 03-01-2012, 10:49 PM

Quote:

Originally Posted by Snowflake

Just to clarify, the speaker was referring to the first kits of the model, not the first kits of the RV-4. No RV-4's have been built with adhesives instead of rivets, to my knowledge.

Does the RC kit actually have metal wings? The Great Plains 1/4 scale one is wood...

Perhaps he's confusing it (the 1:1 scale one) with the similar shaped wings of the Grummans, which do have bonded metal wings....

skylor · #5 03-01-2012, 11:33 PM

Quote:

Originally Posted by Schwemmer

I attended a radio control club meeting the other night and the topic was a model of the RV 4. The speaker mentioned that the first kits had the metal skins "bonded" instead of using rivets. I do know that there are bonding agents and some airplanes use that instead of rivets. Would it be possible to use bonding adhesives instead of rivets on the RV7? would it make the overall gross weight lighter? Has anyone researched this?

Thank you,
Rick

It sounds like the speaker may have mixed up the RV-4 with the BD-4 which I believe was bonded construction.

Skylor

SHIPCHIEF · #6 03-01-2012, 11:42 PM

I always thought the bonded wings of the Grumman planes would start having delaminations and an AD by now.
Just goes to show you what I know...

Once I learned how to rivet sheet metal I started to think it's a pretty good system.
Could you imagine an airplane put together like your fuel tanks

minus the rivets, of course.

Ironflight · #7 03-02-2012, 06:04 AM

Quote:

Originally Posted by SHIPCHIEF

I always thought the bonded wings of the Grumman planes would start having delaminations and an AD by now.
Just goes to show you what I know...

.

As a Grumman refuge (there are many of us here....), I can tell you that there WERE some debonding issues in a couple of early production years - and it was quite a headache for some. But in general, yes - the airplanes have surprised their critics....and trained many a future RV builder/pilot!

krw5927 · #8 03-02-2012, 06:12 AM

In the big-airplane world, we do indeed bond skins with adhesive. However, it's typically only large doublers to skins, which then get rivets all the way through the stack-up.

Metal bond uses a film adhesive rather than a liquid "glue". The preparation for the skins prior to bonding includes, as a necessity, anodizing and a special bonding primer applied by a machine for uniformity. The layup happens in a cleanroom and then goes to an autoclave for curing, much like composite materials. After cure the whole thing gets NDI'd for any disbonds, voids, or porosity in the bond line.

Rivets we can do in our dirty garages.

WingsOnWheels · #9 03-02-2012, 06:38 AM

There was a kit for sale a few years back that was advertised on e-bay and other site. I think it was called the "bulldog" or something like that. It was a two-seat sheetmetal plane based on an existing design (can't remember which). When first advertised, they touted bonded skins, later that changed to pulled rivets, and then they went away. I spoke to the owner of the kit on the phone once and looked over his build log (his wasn't bonded) nice guy, but I wasn't impressed by the kit.

Mel · #10 03-02-2012, 06:41 AM

Originally the Moni Motorglider had bonded aluminum wing skins. They did have a lot of de-lamination problems.
Part of the problem is that the process of "bonding" aluminum is NOT forgiving and most home builders do not have the proper facilities. Bonding aluminum in a well controlled factory is one thing. Doing it in a garage is quite another.