How to Make a Fender Patch Panel

The thin plate metal of car fenders can be easily ravaged by rust around areas of damage, or those in which moisture collects. In these discreetly hidden areas rust can build up and rot the panel away until it needs to be operated upon. A drastic but effective solution is to cut out and remove the affected area and replace it with a patch of similar material.

Instructions

1

Use the angle grinder to cut away the damaged area of the old fender. Don't cut an enormous hole, as this could weaken the bodywork, causing new cracks and splits which will allow the rust back in. Just remove the affected part and all the rust around the edges.

2

Fold the heavy packing paper into the approximate shape of the bodywork and place it behind the hole. Tape it in place using the masking tape and ensure that there is contact all the way around; the paper should fit as snugly as possible to the rear of the bodywork.

3

Spray paint through the hole in the bodywork onto the paper. Allow a few seconds for the paint to dry, then remove the paper. Cut out the painted area. This will act as a template for the patch panel.

4

Stick the template on the replacement piece you'll be using to cut the patch from. Sheet steel of appropriate thickness is fine, but if you can find enough material on a damaged or discarded fender, you can be sure the steel will be of matching thickness and will weld together well.

5

Draw around the template with the marker, leaving around one-eighth-inch extra space to ensure overlap with the hole in the fender. It's better for your patch to be slightly too big rather than too small.

6

Cut out the patch using the angle grinder or plasma cutter. Allow the edges to cool then sand off any ragged excess.

7

Spray the patch with primer and it's ready to be fitted to the bodywork.