Automotive Body Hammers and Dollies

Driving around in a damaged vehicle can add insult to injury. Body hammers and car dollies are the tools needed to make minor collision repairs. The tools can be used on metal, including steel, as well as fiberglass bodies.

What is the body hammer-on-dolly technique?

Specialists use hammer-on-dolly and hammer-off-dolly techniques to remove minor dents and defects from vehicles. It works like this: An body hammer is tapped against the outer part of a vehicle panel while a dolly, also called a spoon, is placed on the underside. This keeps the metal from acquiring further dents while it is being reshaped. Mallets typically tap out the high dents while dollies reinforce the low dents, but roles can be reversed as needed. When the reinforcement tool is placed directly opposite the mallet, then you are performing the hammer-on-dolly technique. When the reinforcement is roughly an inch or less away from the mallet's impact, then you are using the hammer-off-dolly technique.

How do you use a body hammer and dolly kit?

The first thing to do when using automotive mallets and car dollies is to choose your equipment. Curved car dollies are used when a dent is on a curved portion of the vehicle; otherwise, flat ones are used. Body hammers typically have two sides: one is square, and the other is rounded, although there are types that have two rounded edges and others that have one or two pointed edges as well as other options. The shape determines how the mallet's impact is distributed over a specific area. Once you've chosen your heavy-duty tools, there are a few rules to follow:

  • Reverse the damage. Indirect damage is found in the area that received the lowest impact. The general rule is to start on the outside and work your way into the area of direct damage. The heavily impacted area should be the last area you work out.
  • Metal stretches. It doesn't matter if you are talking about aluminum or steel; metal stretches when it is worked. Overworked metal needs to be shrunk, a process that is worth avoiding. Use the "on" method sparingly because it can cause stretching if overused.
When do you use different dent repair methods?

For big dents and heavy damage, start with the "off" method. This method works out major areas of concern without compromising the steel and stretching it. Once the big areas are taken care of, use the "on" method for finer work. The "on" method is typically used for steel edges. Knock out all the big damage before working out smaller defects.