Tips and tools needed for professional no-weld auto body repair panel work

Repairs with patch panels or custom fabricated panels utilizing adhesive can be done with structural integrity far superior to rivets themselves. Repair fenders, quarter panels, trunk floors, firewalls, doors or floor pans quickly and permanently without welding.

Here is the step-by-step auto body repair panel process to great results.

Remove all paint from damages area to expose bare metal. Keep removing paint to expose 1-2" of corrosion free metal around damage, using a 5" stripping disc and mandrel or "DA" sander with 180 grit paper. Scribe cut lines at least 2" from damage or near panel edges or parting lines. Cut lines can also be made under wide side molding or trim, if available.

Next in the auto body repair panel process, feather paint 2-3" around cut lines for later blending. Cut out on scribe lines using a Drill Nibbler or Pneumatic Nibbler. A hand nibbler or shear can be used, but will be a little more difficult.

Then, begin using a panel flanger to neatly and accurately flange around the opening of the cutout section. Adjust the vise grip to produce a deep enough flange for a flush repair. Check flange with a piece of scrap metal of the same gauge to make sure the flange is correct and both pieces form a level surface.

Step four of the auto body repair panel process : layout the dimensions of your cutout area on a piece of cardboard, cut to exact shape and transfer to your patch panel, measuring from the outside of your flange. Cut to shape and check for correct fit, using a straight edge, as shown. Adjust patch panel by carefully trimming to fit level and flush all around flange area. Make sure the patch panel is the same gauge as original panel.

Now, layout the rivet pattern on patch panel, keeping rivet holes centered in overlap area. If the repair kit is setup to utilize #4 flush rivets, you should start the rivet layout at a corner to assure it lays flat when completed, space rivets about 3/4" to 1" apart. This will depend on the area of the patch. If the patch is only 5" long by 3" high when use a spacing of 3/4", if the patch is larger than use the 1" spacing, you will have to use your judgment on rivet placement when nearing edges or opposite corners. Use only aluminum rivets and patch panels on aluminum and steel rivets and patch panels on steel.

Next, in the auto body repair panel work, after the rivet pattern is laid out accurately, clamp the patch panel in place using edge clamps and c-clamps if needed. Make sure to check for flush (level) positioning of panels using the straight edge as before. Start drilling the rivet holes, with a 1/8" bit. Beginning in a corner using blind holders in drilled holes to help secure panel. Once holes are drilled, remove clamps and patch panels and deburr all holes; this will assure a flush repair in the end.

Then, use dimpling pliers to countersink (dimple) all holes in both the patch panel and also the original. If you're not familiar with dimpling pliers drill a few 1/8" holes on a scrap piece and practice to get the feel. After dimpling holes in small panels, you may have to straighten the edges. This can be done with a hammer and dolly in the original panel, and a hammer and anvil on the patch panel.

Once all the holes are dimples, the next step in the auto body repair panel job is to install the patch panel using the blind holders and test fit. The panel should be flush with the surrounding area and follow any contours on the original panel. If the panel does not fit flush, the edges could be deformed, or the original panel holes may not be correctly dimpled. Straighten the edges as mentioned above or increase the depth of the dimpling tool, and reform lower or original panel dimples.

Remove the blind holders and clean flanged area on both panels with a quality lacquer thinner, wipe panels with clean cloth or paper towels to completely dry. Remove cap from two part panel adhesive tube and install mixing tip, slide adhesive tube into clear caulk gun adapter, and install blue adapter onto caulk gun plunger. Before you move on with the auto body repair panel work, check the working time of the supplied panel adhesive to ensure you don't go pass the time. Also note that the mixing tip may not be reusable.

Squeeze a small amount of adhesive onto a scrap piece of cardboard and check for an even mix, which should be a dark gray color without streaks of white. Apply adhesive onto original panel along center of rivet line in a 1/4" bead.

The second to last step in the auto body repair panel work is to Install the patch panel using the blind holders in every hole. Make sure the panel is flush by using a straight edge. Adhesive will be squeezed out along flange area. This can be smoothed with a body filler spreader after rivets are set. Remove all the blind holders one at a time replacing it with a rivet. Soak the blind holders in thinner before adhesive has a chance to set up, failure to do this will render them inoperable. Begin riveting (using #4 flush rivets) at a corner or radius first to keep panel flush. Continue installing rivets working evenly from the start point until all rivets are set. Now use a spreader to smooth the adhesive: this is where the corrosion protection takes place as the entire flange area and seam are protected with the adhesive on both sides of repair.

The final step of the auto body repair panel job (OUF !) : Let the repair sit at least 4 hours for the adhesive to set up before sanding level. After set up time, sand just as you would conventional filler. The adhesive should cure for 24 HRS before applying fillers, primers or top coats. Sand the area smooth and apply filler if needed to produce a flush and professional repair. Use a Self Etch primer on the repaired area and finish as you would any spot repair. Spray the backside of the patch panels with cold galvanizing compound to protect from corrosion. SMC and fiberglass can be bonded with the use of the panel adhesive alone.