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Riv pound Technique?

FuturPilot

Well Known Member
They say if you do the same thing over and over and get the same results, and expect different? You're nuts! I hope I'm not nuts and expect to finish this and actually fly it.
Any suggestions why I'm getting the "smile" on the lower half of shop head?
And, more importantly what can I do to remedy my behavior (technique)?
 

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Could be you just aren’t holding the gun square to the work. However, a common technique flaw, is relaxing the pressure on the gun handle prior to fully releasing the trigger. Try to say to yourself, ‘Keep pushing on the gun for one full second after you release the trigger.’
 
hows your air pressure to the gun? it looks like you're occasionally losing control, this could be too high PSI to the gun, or letting up on the pressure you're putting on the gun+work.
 
I think practice is what will make it better. I'm assuming you are watching the bucking bar as you rivet, seems like you are pulling up on the gun as you are looking over the spar to watch the bucking bar, concentrate on keeping the gun level.

I put duct tape over the end of the rivet set to keep it from sliding, also protects the rivet somewhat.

Air pressure is a balancing act that you need to find what works best for you. More pressure is harder hits, with the benefit of less hits needed to set the rivets, and the downside of the gun being harder to control and more smiles if the gun doesn't stay flush. Lower pressure is lighter hits, takes longer to set the rivet, but easier to control the gun and less damage if it slips.
 
Trchnique

Pressure too high or releasing grip before releasing trigger.
I use black Gorilla Tape. Little square apllied to the factory head. It leaves a little residue easily removed with a fingernail.
 
I recommend watching the gun, not the bar. Feel the bar in place, watch the gun for alignment and placement.
 
Use a little masking tape on the rivet set, turn the pressure down, and watch the rivet set side to keep square. Keep pressure on the gun to break any habit of releasing pressure as you release the trigger as mentioned. Also, try to drive the rivet to completion in 1 pull vs a 2-3 blasts of the gun.
 
Tools,tech, and time

Gorilla tape...check, air pressure lower...check, watch and wait on gun...check.
Will try all of these.
Thanks for the "expert" advice.
 
Gaffer's tape, Scotch cloth wound tape, any cloth type tape works OK, so find one you like and buck on.

BTW, it goes on the rivet set, not the rivet, unless you want to risk getting a piece under the rivet head.
 
rivet set

Make sure you are using the right rivet set. most rivet sets have a -3 and a -4 cupped rivet set. Vans rarely uses the -3 domed rivets
 
Technique's the key.

Try to concentrate on having the gun transmit it's force directly through the gun, perpendicular to the rivet head. The geometry of the rivet gun pistol grip tends to work against this by applying the force roughly in a line running between your hand's palm to the rivet, an upward glancing, deflecting action (evidenced by your smiles mostly appearing in same area of rivet head)
You could try to neutralize this tendency by directing more grip force from the area between your trigger finger and thumb (top half of your grip) & using the other fingers to just stabilize the gun generally.

My personal technique is a bit different again, I hold the gun so that the middle finger is used as trigger & first finger is aligned with the gun 'barrel', this means my palm is positioned more over the back of the gun & force is directed straight down the 'barrel'.

The above tips of using some tape over the set are good too. I use masking tape.

Good luck, practice makes perfect (rivets)
 
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I found the snap caps to be lifesavers on 1/8 universal head rivets.
 

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I rarely comment. But I had same issues. Snap caps and tungsten bucking bars. Wish both of those were in the beginner tool kits. Would've saved me a ton of pain/dents/smileys and internet searches.
 
Pressure

New builder here , ive suffered same results , like others have said with more experience, watch your pressure settings and keep it square feel for the bucking bar and watch your gun ,, it will get better the more you drill out lol
 
Good riveting technique..

Ditto to all the above comments.... although I have never heard of riveting caps. I personally use two pieces of scotch magic tape over the dome of the rivet. It seems to give good results and it keeps the fancy anodization on the rivet.
I have a little plastic tri-square that I use beside the rivet set to be absolutely sure that the rivet set it's self (not the gun), is perfectly square to the work.
It's helpful to have a partner do the eye-balling for you to see if you are square to the work. You would be surprised how far out you can be until you get yourself "calibrated".
 
error

Most common error I see is too much pressure on bucking bar causing rivet gun to bounce.

Watch the gun, not the bucking bar. Put more pressure on gun and just hold bucking bar in place. Covering the end of the rivet gun with tape with help not marking the rivets but your problem is bouncing the gun so won't help you.

Practice make perfect
 
Riveting

I spent a bit of time at a shop the rebuilt Cessna wings. Later one of the partners in that operation had his own shop and for a long time he did a lot of sheet metal repairs. He had a guy on call who did most of the sheet metal work. All I can say is the the rivet guns that people were using in that era had a very different and distinct sound. The frequency of the cycles was much less frequent and there was not as much noise. The gun did not try to jump around the way guns frequently used today do. Never saw any of those people use tape, caps or anything special. I think that having the proper rivet gun is 90% of the solution.
 
AN470 Smiley Prevention

I assume your pic was of a practice plate and not an actual airplane part. One thing I have not seen mentioned yet is to ensure that you secure/clamp your work properly. If your gun's air pressure is too high, AND the parts you are riveting are allowed to move/bend/flex/vibrate too much, this can also cause the rivet set to bounce off or reposition itself at an angle to rivet head, resulting in a smiley.

So ensure that your parts are clamped down and apply consistent pressure with the gun against the rivet head, and verify the parts cannot move or flex too much. Then experiment with different air pressures on the gun. Start low and work your way up, and this will allow you to get the feel for how the gun needs to be held on the rivet head as you reach the correct air pressure.

I also use the tape on the rivet set, and I also ground down a very small amount of metal on the tip of my cup set and smoothed/polished the edges, which I personally think resolved more of my smiley problems than anything else. I got that tip from a post that mentioned that the rivet sets from some companies tend to grind the cup a little too deep, making it very easy for the edges to contact the skin surfaces and create smileys. The goal is to remove just enough metal on the tip so the cup is still covering the dome of the rivet, but the edges will sit just a bit higher against the work.

Another tip is to ensure that your body/arm position is as directly in line with the rivet gun as possible. if you stand to one side or extend your arms to the side of the gun too much, this has the tendency to cause the gun to skew to one side or the other as you start pounding the rivet.

While the instructions to place the rivet set/gun "perfectly" square to the rivet head is the ultimate goal, I don't think I have ever been able to tell when my gun and cup set are truly square to the AN470 rivet head. So you do the best you can with that, and combine that with all the other techniques and tool/air changes suggested in these comments, and you should be able to overcome most of the smileys.
 
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