For custom classic truck enthusiasts, one of the most rewarding moments comes when someone asks who handled a particular construction phase of your truck and you can say, “I did.” That is particularly true when it come to something as obvious as bodywork.
If you’re rebuilding an old truck bumping out dents generally is part of the process and when that time comes a decision will have to be made, either pay someone for their time and talent or learn to do it yourself. It’s understandable that the though of attempting bodywork for the first time is downright intimidating, especially when you look at an entire truck. But a less scary approach is to look at one part at a time. Start with something simple, like a dented fender and ignore the rest, and if you’re still nervous, think of all the money you’ll save.
In most cases sheetmetal repairs are done in the reverse order of the way the damage was done. As an example, if you ran into a fence post and the damage started at the front of the fender and continued for 18-inches or so to the rear, the repair process would start at the end of the crease and move forward. If the damaged panel has some crown to it, a hammer alone can be used to bring the metal back to shape. But more than likely a hammer and dolly will be used together.
There are two techniques for using hammers and dollies—hammering on dolly and hammering off dolly. Hammering on dolly is like using a hammer on an anvil. To repair the damaged area a dolly that is similar in shape to the panel is used. Using a low crown hammer, start the hammering around the edge of the damage, overlapping the hammer blows by half the diameter of the hammer’s head as you work towards the center. As hammering on dolly means the metal is squeezed between the two, being too aggressive with the hammer blows will result in the metal becoming thinner, which means it stretches. That material has to go somewhere so it will often “grow” in the direction of the pre-existing high (or low) spot.
When hammering off dolly pressure is applied to the low spot with the dolly from the backside of a panel and the high spot is hammered from the front, this will simultaneously raise the low spot and lower the high spot with little or no stretching.
To get started in bodywork there are a few tools that should be in your garage:
These come in a variety of sizes, shapes and weights. The heads are usually round or square and the faces will have a slight convex shape in the case of a low crown hammer, or more curvature as on a high crown hammer. In any case a flat-face hammer should never be used for body work as more often than not the edge of the face will put a “smile” shaped impression in the surface if a blow lands other than square.
In most cases a low crown hammer will be used, as it will spread its impact over a larger area than its high crown counterpart. That means there’s less of a chance the metal will be stretched. However, the shape of the panel must be considered when choosing a hammer. The curvature of the hammer’s face should be greater that the panel being repaired to prevent the edges of the hammer from contacting the metal. Along with the square or round head on one side, many hammers will have a “pick” on the other. Used to raise low spots, these picks may be pointed or chisel shaped.
Another common type of hammer face is the shrinker. These can be found with a simple crosshatch pattern or more aggressive “meat tenderizer” face. In either case the effect is to displace metal and tighten, or shrink the surface.
There are dollies available in every conceivable shape and size and generally weight two pounds or more. Good dollies are made from forged steel, the cheaper variety are cast iron.
To get started a beginner...
To get started a beginner set of hammers is good enough. These came from Harbor Freight and include round faces, square shrinking head, pointed pick and a cross peen.
The faces of body hammers...
The faces of body hammers are crowned to keep the edges from striking the surface being repaired. This is a low crown hammer
This hammer has a higher crown....
This hammer has a higher crown. It may be more appropriate on curved surfaces than the previous hammer. When used on a flat surface the contact point is smaller and more concentrated.
We were lucky to be given...
We were lucky to be given a variety of hammers and dollies once owned by a body may who worked in the Thirties. This small, high-crown hammer was used for straitening stamped character lines.
Another specialty hammer with...
Another specialty hammer with a small, high crown round head and a pointed pick.
There are times when the proper...
There are times when the proper tool for the job doesn’t exist, in that case some creativity is required.
Note the difference in size...
Note the difference in size of these hammers with the same style head. There is also a considerable difference in weight.
Here we have a shrinking hammer....
Here we have a shrinking hammer. The texture of the face compacts the surface of the metal, effectively shrinking it, however a rough surface is left behind.
Here’s the heavy hitter of...
Here’s the heavy hitter of hammers shown with something conventional for comparison. This hammer is virtually impossible to swing and is more often put against the work and hit with another hammer, or used as a dolly.
Speaking of dollies, here...
Speaking of dollies, here are just a few of the common configurations. When shopping dollies choose the forged variety.
This is an example of hammering...
This is an example of hammering on the dolly. A common practice, use care when hammering this way to prevent compacting the surface, which serves to stretch it.
Hammering off the dolly is...
Hammering off the dolly is an effective method to knock down high spots and raise low spots simultaneously without stretching. The dolly must be held tightly against the surface.
Spoons come in a wide range...
Spoons come in a wide range of sizes and shapes, A true multi-purpose tool, spoons can be used as a dolly, pry bar, and even as a slap hammer.
A surprisingly simple tool,...
A surprisingly simple tool, a suction cup can be used to pull out a panel that isn’t kinked.
For welding holes in sheetmetal...
For welding holes in sheetmetal these copper backup pates are extremely handy as the welding wire won’t stick to it. Some plates have handles, other have captured magnets to hold them in place. These are from Eastwood.
For versatility each dolly usually has a variety of contours so matching the shape of its surface to that of the panel being repaired shouldn’t be too difficult.
These can be used like a dolly in situations where space is restricted. They can also be used to pry, and in some cases even used as a “slap” hammer. Like hammers and dollies, spoons come in a variety of sizes and shapes.
Bodywork requires the use of a variety of abrasives ranging roughly from 24-grit to around 320. Coarse abrasives are used to quickly remove old filler and paint in damaged areas and that is generally done most effectively with an air driven grinder.
For featheredging paint, preparing for the application of body filler or refinishing materials, finer grits are used on a DA, or a dual-action sander. Air driven, these sanders have two modes, circular or oscillating, or random orbit. In the oscillating mode, which is used more often, material is removed faster and with less likelihood of abrupt edges.
Unfortunately, explaining how to do bodywork is like trying to tell someone how to ride a bike, the best way to do either is to jump on and give it a try. Equip your shop with a few basic body tools and try some minor repairs. As you gain ability and confidence, consider some of the additional tools and equipment we’re showing here. And, of course, watch the pages of Custom Classic Trucks for more tips on doing the bump and grind. CCT
More cool tools to have, especially...
More cool tools to have, especially when installing patch panels are clecos. The style on the left can is put through holes in the replacement panel and the body to hold the two together. In the middle is the clamp style that holds two panels together, and on the right is the installation tool for both. These are also from Eastwood.
Another neat piece from Eastwood...
Another neat piece from Eastwood are panel clamps—they hold a patch panel in place and provide the proper gap for welding.
An inherent part of bodywork...
An inherent part of bodywork is sanding, and the proper way to do that is with blocks. It can be a small hand block or a long board, but they are the key to making a repaired and primered surface flat.
This is a body file typically...
This is a body file typically used with lead, however it has a number of other uses as well.
Body files are normally attached...
Body files are normally attached to handles. They can be used to file lead, but they can also be used to identify high and low spots.
This adjustable handle is...
This adjustable handle is used to flex a body file to match the contour of the metal. Filing on bare metal should be kept to minimum to avoid removing too much material.
For most of us even after...
For most of us even after we’ve done our best, some body filler will be required to make the repaired surfaces perfect. You’ll need a variety of spreaders to apply it.
Commonly called a cheese grater,...
Commonly called a cheese grater, this file is used to shape body filler before it hardens completely.
A small grinder has a variety...
A small grinder has a variety of uses; it makes quick work of removing paint from damaged areas and flattening welds around patch panels.
The venerable DA sander can...
The venerable DA sander can be used to remove paint, featheredge layer of finish materials, smooth filler and remove surface rust. This example is from Harbor Freight.
An air powered long board...
An air powered long board makes quick work of sanding large surfaces flat. Another tool from Harbor Freight.
Handy for getting into confined...
Handy for getting into confined areas, the angle grinder/sander from Harbor Freight uses stick-on sandpaper pads.
Some tools are simple, a wood...
Some tools are simple, a wood dowel wrapped with sandpaper works great for smoothing concave surfaces.
If you plan on making your...
If you plan on making your own patch panels nothing beats an electric shear.
This is a panel flanger (if...
This is a panel flanger (if also punches holes). After cutting out a damaged or rusted section, the flanger can be used around the edges of the hole.
By stepping the opening the...
By stepping the opening the patch panel can be welded in place and the edges will be flush the outer surface.