How to Install Buck Rivets

by Steve Bryant

Even if you have never riveted before, it isn’t very difficult to learn. Some intentional practice on scrap pieces of metal is definitely in order! By practicing riveting using metal that will not be used in your trailer, you’ll be a lot more satisfied with the results when you do start work on your pride and joy.

Here are most of the major considerations related to bucked or driven solid rivets: 

1. Solid rivets are superior to (strength/waterproofness) and less expensive than aluminum blind rivets. 

2. Installation of solid rivets requires access to the front and back sides of the parts being riveted. 

3. Holes for solid rivets should be very slightly larger than the rivet’s outside diameter prior to being driven. 

4. Install Clecos (item VTS-821) to hold all parts to be joined with rivets as the holes are drilled to minimize any shift in position between parts. (Note: as you rivet the parts together, some holes may need to be chased or cleaned-up with a drill bit again due to minor shifting of the parts.)

5. A pneumatic rivet gun, rather than an air hammer, must be used to drive bucked solid rivets.

6. With small assemblies, a single operator can usually drive the rivet with the rivet gun and hold the bucking bar against the tail of the rivet during the bucking or upsetting process. 

7. Larger panel assemblies require two operators: one to drive the rivet and the other who will buck the rivet. 

8. The air pressure regulator on the rivet gun should be set such that about 6 or 8 impacts with the rivet gun will fully  drive the rivet. 

9. The proper rivet set should be installed on the rivet gun according to the style of the rivet heads being driven. 

10. The spring attaches the rivet set to the rivet gun. It should be removed from the gun to allow the rivet set to be installed and then replaced over the base of the rivet set and screwed down securely. 

11. The riveter (person operating the rivet gun) should: a. Place the rivet set squarely over the rivet head. b. Align the axis of the rivet gun so that it is perpendicular to the surface of the parts being riveted. c. Apply several pounds of pressure against the rivet head. d. Verify that the bucking partner (if one is involved) is ready to begin riveting: call out “Ready” and wait for an affirmative response. e. Squeeze the trigger on the rivet gun for about one second and check the state of the shop-formed head or await the verbal report from partner doing the bucking. f. Repeat as necessary. 

12. The person bucking the rivets should: a. Evaluate the length of the tail of the unformed rivet for length: it should protrude about 1.5 to 2.0 rivet diameters from the back side of the surface being riveted. b. Place the surface of the bucking bar against the tail of the unformed rivet so that the surface is perpendicular to the axis of the rivet and the mass of the bar is in line with the strike of the gun so that the force is absorbed and deadened most effectively. c.  Apply a slight pressure against the rivet (one or two pounds of pressure, but not enough to push the rivet back through the hole or lift the rivet head off the metal surface). The bucking bar pressure should be much less than what is applied to the rivet gun. d. Communicate with your partner that you are on the correct rivet and ready to begin riveting. e. Evaluate the formed shop head:the tail should protrude about 1.5 diameters before forming and the shop head diameter should be approximately 1.5 times the rivet diameter after being driven. f. If the rivet has been driven too much (shop head is too thin and flat), the rivet will have to be drilled out and replaced.

Important Note for Repairs Using Bucked Rivets When you have to drill out old rivets it is important to leave a properly sized round hole. If the hole is not sized and shaped correctly, the new rivet will not swell to fill the hole fully and the rivet may leak. Repairing an old hole usually requires enlarging it and installing the next size larger rivet. An old misshaped 1/8” rivet hole can be “saved” by using 5/32” replacement rivets. You may also want to install the new rivet in a “wet” fashion: inject some type of sealer/caulking appropriate for aluminum, such as TremPro (item VTS-267) to seal the hole. Also, consider installing additional rivets nearby to carry the structural load if that seems prudent due to multiple distorted 

A number of good resources (written material as well as videos) are available via an internet search. 

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