Pop Rivets - Rivets Done Right

If you race on a short track long enough, sooner or later you will need to repair sheetmetal. It may be at the track, at the shop, or in your driveway at home, but you will need to patch a hole, repair a piece of torn sheetmetal, or replace an entire body section. And you will need to make this repair utilizing rivets, as opposed to using bolts or welding on a new body section.

Even basic fabrication outside of damage repair requires that many parts of the body be held together with rivets. For the most part, the rivets of choice are pop rivets.

Pop rivets make working on race cars both frustrating and very rewarding. They are quick and easy to install, and even if you install them a little less than correctly, they still seem to work pretty well. They are lightweight and help create a very strong structure when properly installed. They are optimal tools for joining dissimilar materials, such as aluminum patches on steel body work, or mounting plastic body panels to steel bodies, such as the nose on your Street Stock or Modified. They are perfect low-tech fasteners that give a very high-tech look and finish without the high price. By comparison, pop rivets are much more economical than nuts, bolts, and washers.

As with any other process, there are rules-always rules. Pop rivets are not a one-size-fits-all type of product, although many racers seem to think that if the rivet fits into the hole it is the right rivet. Nothing could be further from the truth. Rivets come in different sizes and lengths to fit a variety of applications. The head of the rivet is also something that the racer needs to be aware of to get the most out of the part. Using the wrong rivet can yield a joint that's weak and could even cause interference with other parts in the car. Planning and forethought are still required.

From the standpoint of infrastructure, the tools required to install pop rivets can be obtained from a number of different sources, and the range in price is just as broad. The tools you need to install pop rivets can be found everywhere, from the local hardware store to the major chain stores. Speedway Motors, listed at the end of this article, is an excellent source. What separates the racing vendors from the local hardware store is the type of rivets that are available and the rivet accessories. Racing vendors typically stock rivets with heads that are much larger than the pop rivets available at the local hardware store. Many of the tools sold by racing vendors are more resilient than the tools found in hardware stores. Racing tools are designed to be used much more frequently, so they're constructed to be much more durable. And you can expect to pay a little more for this product quality.

From the simplest perspective, what is required to install pop rivets? Here's a quick list:
* A drill
* Drill bit(s) of the correct size
* Cleco fasteners and Cleco pliers are very helpful if you are working on large parts or parts that require exact positioning
* Measuring tools, such as a tape measure or a steel scale
* A permanent marker
* A rivet gun
* A selection of pop rivets
* Some backing washers for the back side of the rivet

The majority of the tools you need are probably already in your toolbox. Most racers may not have sets of Cleco fasteners, but these are very inexpensive tools and worth their weight in gold. They are like having several sets of extra hands and can be purchased at many racing supply houses. They are easy to install and just as easy to remove when you have finished using them. They cost less than a dollar each and come in four different sizes that will fit 99 percent of the rivet holes you will ever use. They require a special set of pliers that cost less than $20, and one set will fit the different sizes of Clecos. If you are going to do any sheetmetal work, you will need some Clecos.

The process starts out like any other, at the beginning. If you are going to patch a hole in sheetmetal, you first need to prepare the hole. This entails the following:
* Smoothing the external and internal surfaces as much as possible to remove any burrs
* Fabricating a new patch that will cover the hole and facilitate room for the rivets and the backing washers
* Measuring the spacing between rivets to ensure enough area to make a strong patch
* Drilling holes the correct size for the rivet you are going to use
* Deburring the holes after drilling
* Using Cleco fasteners to hold the patch to the body or panel while you install the rivets
* Removing the Clecos and installing the rivets in the remaining holes

When the time comes to install the rivets, you will want to use a backup washer to help spread the load and the clamping force of the rivet over a greater area. These are special washers designed to be used with rivets. You will only find these at the industrial or racing suppliers of rivets. These will not be part of the selection at the local hardware store. Using backup washers will result in a much stronger and more durable joint than one using the pop rivet alone. Often, you will find it difficult to use the backup washer due to physical constraints, such as when the rivet is going to a location you can't reach to install a backup washer. The rivet industry has a substitute that will give you greater load distribution without having to use the backup washer. It is called a Tri-Fold rivet. This rivet separates into three legs that spread the clamping force over a greater area, much like the backup washer.

Having special rivets that don't require backup washers doesn't mean you should abandon the idea of using the washers. The use of a backup washer makes a very clean, very strong joint. It is the preferred method and you will get a stronger joint that will last longer.

If you are going to be using a good number of rivets, you may want to invest in a more expensive rivet gun. As stated previously, you can get low-cost units for $6 to $10, but after you install several hundred rivets you will have forearms like Popeye the Sailor Man. The more industrial units have better mechanicals and greater leverage that makes them easier to use.

If you are going to rivet plastic to steel or aluminum, you need to use rivets with a head diameter as large as possible, and you will have to use more rivets per inch than if you were just riveting metal panels. It is best to consult with the manufacturer to get recommendations on installation.

When you purchase rivets, you need to look at the fit of the mandrel, the part of the rivet you will be pulling out. This is what gives the pop rivet its name, as the mandrel "pops" out. If the mandrel is loose or much smaller than the hole in the rivet head, this can cause a problem when you are installing the rivet. The bottom of the rivet may not collapse evenly and the rivet will not exert the full force you need to hold your project together.

Sooner than later, you will be forced to remove a pop rivet to make a repair or modify an existing structure. Avoid the temptation to drill out the rivet. This always results in a larger hole. Instead, grind off the back of the rivet and push it out of the hole. This results in a much cleaner repair and does not enlarge the rivet hole. Plus, it doesn't damage the surface of the car or sheetmetal panel.

The process is not very difficult, and if you take your time you will have a patch that is strong, good looking, and quite durable. Just take your time and measure twice and cut once.

The author can be reached at vahok.hill@cox.net.