Universal Head "Edge" After Riveting

iwannarv · #1 01-09-2010, 04:11 PM

When riveting universal head rivets, many seem to be developing a 'lip' or edge on mainly one side of the rivet. This may happen every 1 out of 4-5 rivets. I'm sure that the structural strength is just fine (heads are still round), but when I, the picky builder, look at them in person, they look horrible. I may also be trying to be too much of a perfectionist.

Here is a picture of a good rivet next to one of my troubled ones (RV3 HS Spar):

I don't like frequency that this is occurring, and I assume that I need to bump up my gun pressure (2x at 40-45 psi, 1/8" rivets) to drive them a bit faster. The driven ends check fine with a gauge and are uniform.

Looking for a peace of mind that I am becoming too anal-retentive and just need to shoot some primer on them so I stop looking and just build the thing... (but please, your honest opinion on the rivets)

ChiefPilot · #2 01-09-2010, 04:20 PM

A 2x gun at 45 PSI does seem light for 1/8" rivets; I use 75 PSI for my 3x gun when driving them.

EricB · #3 01-09-2010, 04:33 PM

I start at about 55-60 psi and go up as the rivets get longer. Try a higher pressure, should help a bit. I don't think either of those rivets need to replaced unless its for cosmetic reasons.

Also, get some Snap Socs from Avery tool. They are great and are well worth the money if you want to maintain the appearance of the factory head.
http://www.averytools.com/p-884-snap...-set-caps.aspx

Eric
RV-7
FWF/Cowl

Kyle Boatright · #4 01-09-2010, 04:33 PM

Sometimes a bad rivet set can cause that problem. Sometimes, it's the user. ;-)

I inherited a universal rivet set that didn't have a deep enough dish on the driving surface. It caused defects that looked like what you have. I eventually replaced it and the new set (probably from Avery or Cleveland) which didn't cause the same problem.

Later, just to see if it was a skill/technique thing or an equipment issue, I drove a bunch of practice rivets with the old and new sets. The old set still made smilies, whereas the new one never did.

Rick S. · #5 01-09-2010, 04:34 PM

They're OK, what's happening is the rivet set is bouncing on the rivet. Try placing a piece of masking tape on the head before riveting. I was amazed how much better the heads endured the process. I have a 3x gun and for universal -4 I ran about 55 psi More air pressure makes faster hits only means you'll smile that rivet head faster

It's all technique, looks like you doing good, the tape will help.

roee · #6 01-09-2010, 04:36 PM

Actually, both rivets in your photo show a related problem. The one on the right has an indentation on the rivet head, as you described. The one on the left has an indentation in the spar itself, right next to the rivet. Both are likely the result of you not keeping the set lined up properly (centered and straight) on the rivet, or letting the set bounce around while riveting.

Quote:

Originally Posted by iwannarv

Here is a picture of a good rivet next to one of my troubled ones (RV3 HS Spar):

OneCharlieKilo · #7 01-09-2010, 05:14 PM

Quote:

They're OK, what's happening is the rivet set is bouncing on the rivet. Try placing a piece of masking tape on the head before riveting. I was amazed how much better the heads endured the process. I have a 3x gun and for universal -4 I ran about 55 psi More air pressure makes faster hits only means you'll smile that rivet head faster It's all technique, looks like you doing good, the tape will help.

I used masking tape as well, but on the gun rather than the rivet head. Putting a small piece of masking tape over/in the cup on the rivet set helped eliminate this for me. Had to replace it relatively often as it wears through, but it worked for me.
I generally used about 45-50 psi (at the compressor, using 50' hose) with 3x gun.

GAHco · #8 01-09-2010, 06:41 PM

I have seen this and done this also.

When you press the rivet set on the universal head rivet and press down, the pressure might not be fully in line with the rivet.

This may happen even if all is square. A regular rivet gun has the barrel and the handle.If you put excessive pressure on the handle farther away from the barrel it will cause a swiping action at the end of the set relative to your starting position. If its real bad you will get a series of smiley faces across your skin, if this is just barely happening it will look like the rivet your concerned with.

The trick is to not put excessive force but let the pneumatic rivet gun do the work while you keep it in the correct position.

If you think 1/8" rivets are bad at this the 3/32 universal heads can be worse. Fortunately you dont have them on the Vans models.

Best wishes!

iwannarv · #9 01-09-2010, 06:56 PM

So should I go ahead and drill out the affected rivets, or is this not much an issue of quality of strength, just purely cosmetic?

GAHco · #10 01-09-2010, 07:33 PM

Quote:

Originally Posted by iwannarv

So should I go ahead and drill out the affected rivets, or is this not much an issue of quality of strength, just purely cosmetic?

If there is no space under the factory head, and the buck tail looks right, it should be structurally sound.

If you do drill them out, use a #30 drill and don't drill deep enough to go into the skin level. Put a 1/8" punch in the hole and crack the head off.

You can then pop the tail out with an automatic center punch, or a regualr punch and a small ballpeen hammer.

Caution, you will probably need to support the aluminum on the tail side so it does not get distorted when you drive the old rivet out.

Best wishes,