Several years ago, ABRN spoke with a retiring shop owner who bemoaned the loss of metal working skills in the collision repair industry. "We no longer fix metal." he stated. "At best, we simply replace parts."
Certainly, a lot of that is true. The metal working part of the industry has largely slipped away because manufacturers and insurers recommend part replacement most of the time due to cost and other issues, such as the performance of carefully calibrated safety systems. That doesn't mean metal fabrication has no place in a modern shop. Some repairers practice this art as part of restoration services or race car building. Others shops turn to metal fabrication when parts aren't available or when it's the only affordable option for customers looking to extend the lives of older model vehicles.
These services all can provide valuable revenue streams and create opportunities to win new customers. Interested? With an assist from the experts at the Eastwood Company, here's a look at a common metal fabrication repair, along with the basics you should know before performing this work.
Before beginning
Regardless of what level of fabrication work you intend to perform, your employees will need training and practice--lots of practice--to develop marketable fabrication skills. You'll need to set aside time and invest in materials and parts to allow workers to fine tune their fabrication abilities. You also should look for an instructor, fabrication expert or non-competing shop that offers these services you can use as resource when you have questions.
Tools of the trade
Adding metal fabrication services usually doesn't involve a significant investment in equipment, since your shop probably already has most of the necessary tools. Review the following list of requirements to ensure your shop is properly stocked.
Metal cutting
Tin snips - Straight, right and left hand tin snips (also called aviation snips) are key pieces of fabrication work. They're typically color coded: yellow for straight cuts, red for left hand cuts and green for right hand.
Electric metal shears - A power version of tin snips, these shears use rotating jaws to slice through steel up to 18-gauge thick.
Throatless shears - Throatless hand shears cut through 14-ga. mild steel and 18-ga. stainless steel using a rack and pinion gear design with an extended handle to significantly increases leverage and cutting power.
Angle Grinder - Used for rough cutting, cleaning up body work to be patched, and cutting patch panels from parts cars, a 4.5 in. abrasive cut off wheel also can slice through multiple layers of sheet metal.
Plasma cutter - A plasma cutter is needed for thicker metals and irregular shapes that can't be properly cut with metal blades.
Joining tools
TIG welder - TIG welding is the preferred method of welding patch panels since it burns cooler, and distorts panels less often compare to a MIG welder. It also is less likely to burn through the metal.
MIG welder - MIG welders can be used for thin sheet metal work if the employee is experienced with this work. Usually, MIG welder are too powerful to weld body panels without burning through the metal.
Clamps - Magnetic and mechanical clamps and holders keep fabricated patches in place. Intergrip panel clamps work best for butt welds.
Forming tools
Hammer and dolly - Still necessary for most metal shaping jobs, these tools require significant practice to master.
English wheel - Creates compound curved panels from flat pieces of metal. This tool also requires plenty of practice to master.
Sheet metal break - Creates boxes, brackets and other simple shapes using only straight edged bends.
Bead rollers - These tools add strength to thin access panels, trunk floors, floor pans and other areas. They also can be used to make professional looking louvers for hoods and trunk lids and can form curved panels for things like roll pans.
Panel patching steps
The following steps describe how to remove chrome plastic fender vents and replace with a solid steel patch to create a more unique, sharper profile on a truck. This is a popular exterior modification. The directions here can serve as a model for performing other similar fabrication services.
Step 1. Pry off the vent using a plastic trim tool to reveal the recessed area underneath.
Step 2. Create a template for the replacement metal. Cut a rectangular piece of poster board slightly larger than what will be needed. Use masking tape to attached it to the fender fully covering the vent area. Using a marker and your finger, press on the edges of the recessed area and draw several plus signs, one in line with the edge and one perpendicular to the edge, to create an outline of the vent. Do this along the entire outer edge of the vent area. Use a ruler to connect all the intersecting points. Complete using a ruler and an exacto knife to cut out the template.
Step 3. Test the template by fitting into the vent area. It should sit as flush as possible to reduce the amount of filler and additional body work later.
Step 4. Carefully trace the shape onto a piece of 18-gauge steel.
Step 5. Cut out the shape with a plasma cutter using two pieces of 1/4 in. bar as a guide to make the cuts straight.
Step 6. Attach a 60 grit flap disc to a 4.5 in. grinder and remove the burrs and any surface rust. Bevel the edges to ensure the patch sits flush with the panel, which will help provide a much cleaner weld.
Step 7. Curve the patch piece to match the slight curve of the factory with a bench top English wheel. Carefully apply only forward and backward pressure on the patch in line with the wheel. Placing too much side pressure on the patch will create a dome that will not match the contour of the fender. You can also avoid creating a dome by placing a rubber band over the upper wheel. Doing so reduces the side-to-side stretching of the metal since the band stretches in its place.
Step 8. Test the panel patch. Use a magnet to hold the patch piece in place. Examine the fit and gaps from multiple angles to make sure no corners are too high or out of place. If necessary, grind any unsatisfactory areas into shape. Spray the back of the patch with a self etching weld thru primer to prevent rusting from the inside.
Step 9. Prep the panel area. Place a flap disc on a 4.5 angle grinder. Remove the paint down to the bare metal all the way around the areas that will be welded.
Step 10. Fit the patch into the panel in the proper position. Using a TIG welder, tack weld the panel into place.
Step 11. Examine the weld. If the patch is no longer sitting flush, you can adjust it without having to cut the piece out to save the welds. Using a wide flat blade screw driver, put half of the blade on the patch and half on the panel. Press the patch so it sits just below flush with the opening; then place a tack weld right above the blade. If the panel sits too low in the opening, use a very fine flat blade screwdriver to pry the panel up to the desired depth.
Step 12. Apply filler. Experts recommend contour short strand fiberglass filler since it's much stronger than ordinary filler, allowing techs to apply it in much heavier portions to fill larger depressions and gaps. Before application, clean the area with a pre-painting product to remove any contaminants that can impede adhesion. Apply the filler on all the weld seams, as well as the top section of the patch (the lowest areas need the most support). Note that short strand fiberglass filler is very tough and hardens quickly.
Step 13. Begin sanding 10-15 min after the filler application using 40-60 grit paper to remove the high spots. Then, use 80 grit to level the rest of the area.
Step 14. Apply a contour glazing putty to finish the panel.
Step 15. Apply primer to seal the area. First, wipe down the area again with a prep cleaner. Tape the area about 5 inches off the filler edge to prevent primer overspray. Apply a 2K urethane primer surface. Start from the outside and work your way in.
Step 16. Use 320-400 grit paper on a block to remove any imperfections.
Step 17. Prep the repair for painting. Block sand the entire repair area with 400 grit paper to remove sanding scratches. With a red scuff pad, scuff the existing paint to create a uniform painting surface that will help the base coat stick. Wipe off the panel one more time with the cleaning product; then use a tack rag to remove any lint or dirt from the painting surface.
Note that fiberglass filler material can create more dust and contaminates than other body filler. You'll need to take extra steps to thoroughly remove these particles to avoid having them setting into fresh paint. Always use a blow gun to move as much dust and dirt away from the area surrounding the panel and dust the floor thoroughly.
Other notes
While you continue to build fabrication skills, two areas you'll want to address are marketing and pricing. Your business will need to investigate what fabrication services will be most in demand in your area. From there, you'll need to address competitive pricing to make sure you're properly compensated. A quick audit of competitors' charges can help here. Labor rates should be superior to what you collect from insurance-paid work.
Considering your start up investment will be relatively modest, metal fabrication can be a great fit for a number of shops, especially smaller, standalone businesses. Indeed, adding a service that can help these repairers survive in the shadow of growing regional and national MSOs is no small feat.
