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  #11  
Old 11-10-2017, 02:53 PM
sblack sblack is offline
 
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Location: Montreal
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my -4 rivets all had an indentation around the periphery of the rivet head. I bought new sets - same @#$% thing. I tried different pressures, couldn't figure out the problem. Since the ring was symmetrical, I knew I was straight on the rivet. I tried pressing harder on the bar vs the gun and vice versa. What solved it for me finally was using a heavier bucking bar. The one I used for the -3 rivets just wasn't cutting it. So you could try that.
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  #12  
Old 11-10-2017, 06:00 PM
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rv6builder rv6builder is offline
 
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For -4 rivets I run 60psi, and that bucks pretty quick. Can take a bit longer in thicker material, so sometimes Ill bump the pressure up a bit.

As for the factory heads getting marked up, put a layer or two of masking tape over the end of the set. A structures guy I worked with once went as far as putting prop tape over the end. The biggest killer for me was side force on the gun, once I got used to straight down pressure it almost does away with the need for tape.

Maybe it'll help maybe it wont!

Good luck

Alex
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  #13  
Old 11-11-2017, 10:23 AM
Joe Walker Joe Walker is offline
 
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Aged rivets?
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  #14  
Old 11-11-2017, 10:31 AM
Nova RV Nova RV is offline
 
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Location: Leesburg, VA
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My guess is the brass regulator is reducing the volume of air and making the rivet gun anemic, you are getting perhaps good pressure but no volume. Remove it as someone else suggested and set air pressure in the 50-60psi range and give it a go.
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  #15  
Old 11-11-2017, 04:41 PM
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maniago maniago is offline
 
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Restrictor? Get rid of that. I run my ATS Pro 3x wide open at 100-120 psi at the compressor on 3/8" 100' line, 80psi for -3AD rivets. Tungsten bar for 99.999% of my rivets. 2 flicks of the trigger for -3 and 2-3 for the -4s, usually 3. Sets my rivets like butter.

Yes I run my gun hotter than anyone else. But it works for me and for the people Ive taught to drive rivets on my plane. And I oil the gun regularly.

I dont lean in crazy hard on my gun. Enough to keep it in contact with the metal and slightly more than the bucking bar. For me I also found using painters tape over all rivets (426s and 470s) is da bomb. Cheap, way better than rivet tape in keeping the gun from slipping off mark and if it does, it gives some cushion to that errant hit. I also took the shine off my gun heads with some emery so they have less of a tendency to slip.
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Last edited by maniago : 11-12-2017 at 06:21 AM.
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  #16  
Old 11-11-2017, 07:26 PM
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maniago maniago is offline
 
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sent you a PM
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  #17  
Old 11-12-2017, 06:19 AM
vic syracuse vic syracuse is offline
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As mentioned here before GET RID of tye flow restrictor and use a regulator, just like you would use for a paint gun. Either attach it at the base of the gun, which sometimes makes the gun a little heavier and awkward, or just use the regulator in the line from the compressor.
The problem with the flow reducuer is that on the first few stroke you have ALL of the tank/line pressure available until the flow is enough for the restrictor to actually work. It's way too much, comes out hitting hard, and then slows down, making it really hard to control the gun and the quality of the rivets.
If you want to see a demo so you can better understand it, take your blower attachment or paint gun and attach them first to the flow restrictor, activate the device, and then attach it to a regulated line and activate the device. A picture is worth a thousand words.

Vic
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  #18  
Old 11-12-2017, 08:26 AM
Rupester Rupester is offline
 
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Location: Mahomet, Illinois
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Early on I too struggled with AD4 rivets, despite no problems with 3s. I referred to these very forums waaaaaaay back then, and was told to increase the pressure off my compressor. I goosed it up to 90psi from the previous 50 and that solved the problem completely. Never had a problem after that.
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  #19  
Old 11-12-2017, 09:55 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Default Another viewpoint......

All of the rivet guns in the shop at Van's have the brass colored flow restricter valves installed (have used them for decades). The line pressure in the shop is kept at max. except for pneumatic rivet pullers.
The brass valve is used to control the guns very precisely. IMO, If a gun won't work with one installed, it is either operator error or a problem with the gun (quality?).

The bigger the rivet, the more sensitive is the technique used.
A one pound bucking bar is too small. Bar pressure is important. The gun/rivet set has to be pushing on the rivet harder than the bar. The bar has to be free to bounce on the rivet.
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  #20  
Old 11-12-2017, 12:10 PM
sblack sblack is offline
 
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Aha! So using a bar for a -3 is not going to cut it for a -4.
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