The Key To Metal Bumping Panel Beating Auto Body Repair Biblepdf Upd Jun 2026
What you are facing (e.g., a sharp crease, a soft hail dent, or a structural fold)?
To practice metal bumping effectively, you need a specialized set of hand tools. Each tool serves a specific purpose in flattening, shrinking, or shaping metal.
Apply the on-dolly/off-dolly techniques mentioned above. The mantra is: rather than heavy, smashing blows. 5. Shrinking the Metal
Switch to a finishing hammer and a matching dolly. Use light, precise taps to smooth out minor imperfections. Run a body file gently across the panel; it will scratch the high spots shiny and leave low spots dull, showing you exactly where to work next. Step 5: Metal Shrinking (If Needed)
Using the off-the-dolly technique or a heavy bumping hammer, gently push or bump the main body of the dent back toward its original alignment. Avoid aggressive swinging; light, rhythmic taps are much more controllable. Step 3: Leveling and Picking What you are facing (e
Stretched metal must be shrunk:
Metal bumping is a process that involves using various tools and techniques to reshape and smooth out metal surfaces. The goal is to restore the original shape and appearance of the vehicle's body panels, eliminating any dents, dings, or imperfections. This technique is essential for auto body repair, as it allows technicians to fix damaged vehicles without replacing entire panels.
. This "last-in" area must be repaired first, followed by the next most recent, working back to the original point of impact Damage Analysis
Features a pointed tip on one end used for raising small, isolated low spots from the backside of the panel. Apply the on-dolly/off-dolly techniques mentioned above
If the metal was severely impacted, it may become stretched and loose ("oil canning"). To fix this, you must shrink the metal:
When a vehicle panel is impacted, the metal bends and creates two distinct areas: The direct point of impact.
Striking the metal directly against the dolly's surface to flatten small, concentrated high spots .
Planishing high ridges without leaving distinct hammer marks Step-by-Step Metal Bumping Process Shrinking the Metal Switch to a finishing hammer
Every dent, regardless of size, consists of four basic elements that you must identify during your analysis :
Always work from the outside of the dent toward the center. Knocking down the outer ridges relieves the trapped energy holding the dent in place. Step 4: Shrinking Stretched Metal
When metal is dented, it often stretches. Shrinking brings it back.
Aluminum cannot be stretched; it breaks. It requires special techniques like "pushing" and different heat treatment.
The primary goal is to repair only the areas that have taken a permanent "set" (work-hardened) while allowing the flexed metal to spring back naturally .