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Rivets that won't smash

SantosDumont

Well Known Member
Anyone ever had any rivets that won't smash? I've had a few in my AD470AD4-6 bag from Vans for my RV-14. I've tried the pneumatic squeezer and the rivet gun. Unfortunately they smash just the tiniest bit so I have to cut them off then drill them out.

Thinking I should just throw the whole bag away and order from Spruce.
 
Long rivets

Sounds like they are getting work hardened before fully set. Long rivets can be a challenge. Crank up the pressure on the gun and use a tungsten bar. If not, find a heavier bar. If it's a squeezer, set the ram so it hits the sweet spot.
 
Type?

The regular structural rivets should all have a single dimple in the middle of the head. Some harder alloy rivets may have snuck into the bag. For example, if you see two dashes, they?re the wrong alloy for an RV. (Unless the drawing calls for them, of course) I?ve seen it go the other way when there were some soft, non-structural rivets among the structural ones on a friend?s RV-8 build. If the head marking is correct, those rivets might just be very old. They harden a bit over time. I?m not sure I?d drive them if they?re so hard since they?ll enlarge the holes, especially in thin sheets.
 
I have some very old rivets that are the same type as the ones we use today, just more than 35 years old. I had them before I got my RV-3B kit. They drive exactly like the current ones.

Dave
 
squeezer

Some pneumatic squeezers have an issue with the longer rivets.

Due to the design, you may have to separate the dies so that they do not touch when the squeezer is activated. If that doesn't help, you may have to squeeze them and then reset the dies for the shorter rivet length and squeeze them again.

If you look at the design of the squeezer, it has a sweet spot to generate it's maximum force. Outside of that range, it will not have enough force to properly squeeze the longer rivet.

Seach the forums hear about squeezing longer rivets with a pneumatic squeezer or look up the tutorial from Avery on this subject.

Your squeezer probably isn't broken, you just need to operate it in the correct squeezing range...
 
Some pneumatic squeezers have an issue with the longer rivets.

Due to the design, you may have to separate the dies so that they do not touch when the squeezer is activated. If that doesn't help, you may have to squeeze them and then reset the dies for the shorter rivet length and squeeze them again.

If you look at the design of the squeezer, it has a sweet spot to generate it's maximum force. Outside of that range, it will not have enough force to properly squeeze the longer rivet.

Seach the forums hear about squeezing longer rivets with a pneumatic squeezer or look up the tutorial from Avery on this subject.

Your squeezer probably isn't broken, you just need to operate it in the correct squeezing range...

I had this exact same issue. I thought I had an air supply problem at first. I switched out the rivet set two two thinner sets and then had no issues.
 
With squeezing, it is important to have the tool set correctly, whether it is a pneumatic or hand squeezer. An adjustable set is really important to have because of the many different size and length rivets used. As suggested, it is important to have the tool set for the sweet spot. This occurs at the end of the stroke, so setting the tool so the proper level of collapse occurs at the end of the stroke should yield a properly set rivet. Adjustable sets can easily and quickly be set to the right level. Using washers under sets doesn't always get the correct travel and won't always hit the sweet spot.

Just to clarify something, longer rivets don't get squeezed much more. The shop head is as large as any short rivet. The length is to get it through the layers and thicknesses of the material and to allow some swelling in the drilled hole. The stroke to set rivets is nearly the same for all rivets lengths, but the gap between the sets will be wider for the longer ones.

As mentioned earlier, rivets can become hardened over time. I have heard that baking stubborn rivets in an oven can anneal them and bring back the correct hardness. I do not know the proper temperature or time, but maybe someone on the forum can enlighten us.

Roberta
 
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Over 900 degF. for 2017 alloys to be annealed. They age harden to temper in free air, or through artificial aging process. I consider age hardening after initial design temper is reached to be a wives tale. If aluminum alloys changed temper due to age (after design temper is reached) we would have all kinds of cracking skins and other problems as the temper changed. Doesn?t make sense to me and nothing in my Aluminum Standards manual mentions this as a phenomenon. Anybody have a better reference?
Plenty of folks mention their really old rivets set just fine. Why some and not others? I also have had some very old 75 plus years, rivers tested for alloy and temper. They tested to the Standard.
So, I suspect as others have mentioned, you have an equipment set up or technique issue.
 
I'd never encountered this myself until, early in my -14A project, I found that I all of a sudden wasn't able to properly drive rivets (with a gun and bucking bar, no less) anymore. Since I knew that my technique hadn't suddenly gone away after all these years, I ordered a fresh batch of rivets and the problem immediately resolved itself.

Clearly, something was wrong with the original rivets I'd received with my kit. Whether they'd never been properly tempered, or perhaps they'd age hardened, I can't say, but they were definitely "bad" and the replacements (and every other rivet I've ever received) were not.

Weird, right? :rolleyes:
 
I'd never encountered this myself until, early in my -14A project, I found that I all of a sudden wasn't able to properly drive rivets (with a gun and bucking bar, no less) anymore. Since I knew that my technique hadn't suddenly gone away after all these years, I ordered a fresh batch of rivets and the problem immediately resolved itself.

Clearly, something was wrong with the original rivets I'd received with my kit. Whether they'd never been properly tempered, or perhaps they'd age hardened, I can't say, but they were definitely "bad" and the replacements (and every other rivet I've ever received) were not.

Weird, right? :rolleyes:

Your experience isn?t unusual. I haven?t seen anything supporting that rivets change temper over time. I hope someone has an explanation. Weird is right, but it seems to happen.
 
In the 70's I used to get "new" rivets from Fullerton Air Parts. Picked them up on Thursday, as they were the freshest. Would drive well at 60 psi at the gun. Within 3 days, 80 psi and longer burst.

Then after talking to a "pro" I used the HT ovens at Fullerton Community College. Problem is, Temp control is very important for annealing. 10 degree window at around 925 deg. (from memory, check yours). I think if you exceed 938 you "kill" the rivet.

After annealing (only with clear anodized rivets) they'd drive at 40 lbs in 4 hits as I VERY CAREFULLY tickled the trigger. In 3 days, I was back to 80 psi with the long burst.

Reynolds Aluminum has a reference book. Consider taking the rivets to "W" temper (what most people call "annealing" by burning off Sharpie ink or soot).

Soft rivets stretch the skin the least and results in much better airfoils, etc.

FWIW
 
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