Tip: Shooting long AN4 rivets technique

[scard]

Now that I am about to finish my -9A wings, I think I have finally overcome my struggle with shooting AN4 long rivets. The key is clearly high air pressure at the gun and duct tape on the tip of the rivet set. I am using about 64 lbs. of pressure to shoot (3X gun) the big rivets with a straight set and about 68 lbs when using the offset set. This sounds like a lot, but is what I'm finding works best for me. Any less, and you have to hit the rivet too many times and the metal work hardens and will simply stop compressing because it is now too hard. You can clearly see this happen while you are shooting the rivet. With higher pressure, you hit it much harder fewer times, and the rivet is properly set by the time it is hardened and won't go any further (keep hitting it after it has hardened, and it will start to crack or fracture).

Earlier in my construction, I think I was a little too timid to crank up the air pressure and always battled AN4 rivets when I had to shoot them with the gun. Like those AN4-9 (or so) rivets in the empennage spar hold down brackets. I fought with those things; if I had just cranked the air pressure way up...

[LettersFromFlyoverCountry]

I'm working on the fuselage and just now getting fairly decent at shooting long AN4 rivets. I'm doing most of the work solo and that includes even the outboard ribs, which includes doing all sorts of contortions. So it's important that the technique get ironed out.

I always shooting at around 63 psi, but there is 63 psi and there is 63 psi. I've gotten a fair amount of smilies and dings as things tend to bounce around. And so when I turn the regulator at the gun down, the results are really nice.

Last night I was doing a row of outboard rib rivets and while it's tempting to put the gun on and do brrrrrrrrrrrrrrr, brrrrrrrrrrrrrrrrrr (about a second each), what I found works is more along the lines of brrrrr (to set the rivet) and then brrrrr brrrrrr brrrrr brrrrrr.....very short burts...worked really, really well.

[jimrobinette]

Bob,

That is the best translation of mechanical sound into English I have ever heard! It is almost like being there.

Take care,

Jim

Originally Posted by Bob Collins

Last night I was doing a row of outboard rib rivets and while it's tempting to put the gun on and do brrrrrrrrrrrrrrr, brrrrrrrrrrrrrrrrrr (about a second each), what I found works is more along the lines of brrrrr (to set the rivet) and then brrrrr brrrrrr brrrrr brrrrrr.....very short burts...worked really, really well.

[LettersFromFlyoverCountry]

Originally Posted by jimrobinette

Bob,

It is almost like being there.

If only you were, my back wouldn't hurt so much since I'd have a riveting partner. It's exhausting stuff. To do the outboard rib, I sit in a chair and slouch way down so I can get my arm with the bucking bar under the upside-down fuselage (which is about 2 1/2 feet off the floor) and onto the rivet.

The other arm is held wayyyy up high on the rivet.

Problem I had last night was I didn't have my glasses, so I couldn't tell exactly if the set was on the rivet or not. And then when I did get them, the contortion was such and the humidity such that they were steaming up.

It takes about 2 1/2 minutes per rivet because after you shoot it you have to put the bar/gun down and try to get out of the chair, move the chair, peek at the rivet head to make sure you didn't ding the skin...ah, too much... or put a smiley in things and then crawl under the fuselage, banging my head on the freakin' 705 bulkhead-- again -- and looking at the shop head.

This is why, I guess, I'm closing in on 1,200 hours on the project and I'm only up to hear.

Similar contortions were necessary for the 713 and 719 longerons/stiffeners etc.

But, I'll tell you what, it sure forces you to learn things about riveting. Even with all the hours, I had no idea that the short bursts and turning down the regulator was a much more effective way of dictating the effectiveness of things that screwing around with the psi. I was flabergasted that the rivets set so darned easily and with so little gunw ork.

I even think the short bursts were less disruptive to the neighborhood, although the dog kept barking because he thought someone was knocking on the door.

B

[bsacks05]

I was just curious after reading your post, Scott, if you are using a 2X rivet gun. I tried a 2X once and it was a real pain in the butt trying to set a #4 rivet. For me, a 3X is the only way to go. I don't have a regulator on my gun and I adjust the pressure from the tank to around 20 psi for #3's and 25 psi for #4's.
Bruce
RV9
N659DB
F/F

[LettersFromFlyoverCountry]

The whacky technique described above.

[scard]

Originally Posted by bsacks05

I was just curious after reading your post, Scott, if you are using a 2X rivet gun. I tried a 2X once and it was a real pain in the butt trying to set a #4 rivet. For me, a 3X is the only way to go. I don't have a regulator on my gun and I adjust the pressure from the tank to around 20 psi for #3's and 25 psi for #4's.

I am using a 3X gun.