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Just one of those days (for the third day in a row)

salty

Well Known Member
We've been chugging along nicely on the empennage for our -10 until this weekend. Man, it just seems like we can't do anything right all of a sudden. We're bucking the rivets for the skin into the front spar for the horizontal stabilizer and it's mistake after mistake. We've taken breaks, walked away, stopped early three days in a row now.

Today we both felt really good and we're ready and raring to go, but after driving 25-30 rivets and drilling out 10 of them or more, I called it early again. We've never done so badly. The only good thing about it is that I drilled them all out nice and clean and we got them back in no harm, though it literally took 5 tries for one of them. That was the straw that broke the camels back and caused us to quit for the day.

Somehow we're just in a really bad groove. Hope it ends soon. Send us some positive waves. :D
 
Hey Salty,

I feel your pain. I’ve moved on from the empanage and starting the fuselage last week.
Hang in there. What has worked for me and my rivet parter ( wife) is to take a break and do something else and try riveting in another location. Is there a different bucking bar you can try. Is you body position ideal. What about the lighting. I know when I’m laying on my back in the empanage it’s totally different than standing up with the bar at elbow level. You’ve probably heard this before but take your time. Once you get that first stubborn rivet done it helps bring back the confidence!
Above all try not to get upset with your rivet partner especially if it’s your significant other!

BTW I gave up a while ago on being a perfectionist in this build process. I’m striving for doing the best i can, fix what needs fixing and move on.

It will get better

Keith
 
Bad run

I've had those kind of days. Wife and I had a day we just couldn't get a decent rivet. We were back riveting. I switched the technique over to wife gun and me bad. Everything went smooth. Never figured out why but we don't back rivet anymore.
 
Normally the wife bucks and I drive the gun, but this weekend we tried switching now and then, anything to get out of the funk. Nothing worked. We both made the same mistakes bucking. Nothings changed. Weird how it works.
 
I find that if I am having trouble getting rivets to work the way I want, the best thing to do is walk away from the kit itself and head over to the bench vice with some scrap aluminum and a handful of rivets. Drill a bunch of holes, put the material in the vice, and install some rivets to figure out what I am doing wrong, and how to do it better.

Just like a golfer, you don’t fix a swing problem on the course, you work on it at the driving range!

Paul
 
There could be many reasons why you're having a problem, so go back to the fundamentals. Turn down the air pressure a little so you can control the gun, make sure the gun is perpendicular to the skin, make sure the skin is flush to the spar flange (or rib or whatever), make sure the bucking bar is held firmly but not so hard that it pushes the rivet out of the hole. If you're not using a tungsten bucking bar, consider getting one since it is smaller for its weight and makes riveting easier. Take some scrap and practice until you get your mojo back

Turning down the air pressure a little reminds of the adage about docking a boat that you should only go as fast as you want to hit the dock. It's so much easier to dock a boat slowly and likewise (and especially with the tungsten bucking bars), you can "slow it down" a little and get rid of that feeling that you're out of control. Of course this assumes you have a good quality rivet gun that allows you to feather the trigger.

Good luck!
 
Thanks for all the helpful hints. We've tried them all already. lol

We muddled through the top side over two days of stop and go attempts. Today we set less than 20 rivets on the bottom before calling it. We did practice, we stopped and played with the dog to clear our minds. Then we drive one good rivet and screw up the next. lol

We know what to do and how to do it, we just seem to not be able to do it twice in a row all of a sudden. LOL It really is kinda funny, though very frustrating.

We're not doing any major damage to the structure, I chalk that up to walking away and quitting early enough to prevent things from getting that bad.

We did one goof to the structure on Saturday, but that was an honest human error, and not a huge deal. And we are scratching the primer with the bucking bar more than I'd like, but that isn't too bad either. I think part of our problem is trying not to scratch is screwing up our technique. And yes, we have tape on the bar. It seems like when we scratch we get the rivet set well first try, and vice-versa. lol
 
Tip 1 - to prevent scratches, apply a thin strip of self adhesive weather stripping or duct tape to the back surface of the bucking bar that rubs against the spar.
Tip 2 - to help hold bucking bar parallel to the spar flange evenly, apply a small piece of soft weather stripping at each end of the bucking bar. Doesn't work in all cases, but where appropriate will help to stabilize bucking bar.
Tip 3 - resist using the bucking bar that looks like a hammer (for use in tight areas only). Instead, use the square bucks where ever possible. Expensive but very worth it, get some Tungsten bucking bars!
 
When I kept screwing up rivets, I had a friend come over and work with me. It made a huge difference. See if you can get another builder to drive a few with you and I bet it will help.
 
We finally broke out of the funk and had a good morning of driving rivets. Riveted for over an hour and only had to drill one out - and no scratching!

The weather stripping suggestion is one I hadn't seen before and it worked really well. Also used duct tape instead of painters tape and that worked better as well.

Thanks to all for letting me vent and providing helpful hints.
 
When I'm worried about scratching stuff, I use the crepe type ace bandage on the bucking bar. The kind that only sticks to itself like you would wrap around your arm to hold an ice pack on.

Because its not sticky, if you come to a rivet where access is tight and you need to use the very corner of the bar it's easy to get off. I cut it into strips about 6" long and about 3/8 wide. Thats enough to wrap a couple of layers around a small tungsten bucking bar the long way.

Its the black stuff along the edges of the little bar in the picture.
 

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Curious

I would be curious to see the rivets you decided to drill out...

There is a very good article on mis-driven rivets, I will see if I can locate it. In quite a few cases, drilling out a slightly mis-driven rivets is actually worse than leaving it...the article goes into actually strength testing of the mis-driven rivets as compared to a correctly driven one, and one that drilled and replaced...

Set the bar high but not perfect; perfection is unachievable.

There has never been a perfect build, and there never will be...
 
I would be curious to see the rivets you decided to drill out...

There is a very good article on mis-driven rivets, I will see if I can locate it. In quite a few cases, drilling out a slightly mis-driven rivets is actually worse than leaving it...the article goes into actually strength testing of the mis-driven rivets as compared to a correctly driven one, and one that drilled and replaced...

Set the bar high but not perfect; perfection is unachievable.

There has never been a perfect build, and there never will be...

I only drill them out if they are really bad. Very over driven, not just a little over-driven. Or the bar slipped half off and drove half of the shank and not the whole thing. It was a really bad streak we were having, thus the frustration. Until this streak we've never had to drill out more than 1 or 2 in a hundred rivets at the most.
 
I use the crepe type ace bandage on the bucking bar. The kind that only sticks to itself like you would wrap around your arm to hold an ice pack on.

If it's what I think it is, the brand keyword is "Coban" when you search online for it. I love the stuff, but I hadn't thought to use it for bucking bar padding. I see the appeal, I'm definitely stealing that idea now.
 
You can purchase “Coban” at Walgreens, etc. for about $6.00 a roll but if you head on over to Tractor Supply or any other equivalent feed store, you’ll pick it up for about $2.00. It’s marketed as “Vet wrap”. Just an FYI.
 
My wife (riveting partner) and I fell into a similar funk while doing the top skins on our second wing. We absolutely crushed it the first day getting 6 ribs done in about an hour. Two days later, we struggled through 2 ribs in the same amount of time. We had to walk away for the day. Honestly I don't think the shop heads are really bad, but they aren't as good as I know I can do. I can tell you one thing for sure, I always get a groan from the other side of the wing when I say... "circle that one....."

Not getting angry with your wife who is driving the gun is seriously good advice.
 
I would be curious to see the rivets you decided to drill out...

There is a very good article on mis-driven rivets, I will see if I can locate it. In quite a few cases, drilling out a slightly mis-driven rivets is actually worse than leaving it...the article goes into actually strength testing of the mis-driven rivets as compared to a correctly driven one, and one that drilled and replaced...

Set the bar high but not perfect; perfection is unachievable.

There has never been a perfect build, and there never will be...

It's in Van's Section 5: "The standards to which driven rivets should conform are frequently uncertain. In addition to dimensions and perfection of shape, inspection is concerned with whether the drive head is coaxial with the shank (not "clinched") and whether there is excessive cracking of the heads. It has been determined that even badly cracked heads are satisfactory from the standpoint of static strength, fatigue strength and resistance to corrosion. (Poorly set and cracked) rivet heads were tested in tension to determine how well formed a head has to be in order to develop full strength. The tensile strengths of all the rivets were within five percent of the strongest. The test indicated that minor deviations from the theoretically desired shape of head are not cause for concern or replacement. The second rivet that is driven in any one hole [is] likely to be more defective than the first because the hole is enlarged and [the] rivet will be more likely to buckle and form an imperfect head. Tests have shown that very small rivet heads are sufficient to develop the strength of the rivet shank, even when the rivets are subject to a straight tensile pull....where a large head is not needed for appearance, smaller sizes of drive head should be used to decrease the required driving pressures."

Regarding the last point in the quote, I often found that a series of bad rivets got better when I tweaked the driving pressure.
 
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Every one of my bucking bars is wrapped in Gorilla duct tape except for the bucking surface. If I need to use the side, I just slice off a little with a razor blade. Also, radius at least one edge of the tungsten bars on your belt sander (if yours are not already) so it can nest into the rib flange radius, etc. without beating up the part.

They're tools, not jewels.
 
Every one of my bucking bars is wrapped in Gorilla duct tape except for the bucking surface. If I need to use the side, I just slice off a little with a razor blade. Also, radius at least one edge of the tungsten bars on your belt sander (if yours are not already) so it can nest into the rib flange radius, etc. without beating up the part.

They're tools, not jewels.

I made a number of custom bucking bars from chunks of steel. One of the handiest things I did was JB weld popsicle sticks to one side of a couple of the bars. they help stabilize the bars against a rib without marking up the rib.
 
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