Introduction: Foam Rebuild of Bumper

About: I like to get creative and use materials for their not intended purpose ! Working as a refinishing technician / painter dealing with high end cars ! Lots of fun spend 90% of my time outside and or tinkering L…

Materials need for this type of mold with expanding foam, can work with any vehicle. This project was inspired by drawings

Materials used

-body filler file


-sandpaper 80 grit or coarse

-exacto knives

-sharp knives

-masking tape


-hot glue gun and glue sticks

-large enough piece of fabric to cover entire form

-staple gun

-not needed super 77 spray adhesive

-1/4" plywood for platform and output of existing car bumper contours

Step 1: Cardboard Structure

I had made several drawing beforehand to create the idea and look I was going for. Based my cardboard construction on the drawing and the body lines

Constructed a cardboard form on a piece of wood to the desired idea of the bumper, that also fit to the outer of the existing bumper from my car at the time

I used the hot glue gun to get the cardboard to stay in place

Step 2:

Step 3: Adding Expanding Foam to the Cardboard Structure

With an assortment of body filler files and sandpaper you can achieve the look you want with the curves and body lines you desire .

I used the expanding foam in-between the cardboard bits at a time then carved them the next day to ensure a full cure from the expanding foam since laying up in bigger sections

depending on how much of an area you fill will depend on time of cure, keeping in mind the working temp for the matter in the can.

shave off and use marker to create ideal body lines

Also sharp knives or exact blades were used in the process of cutting the foam

Step 4: Sculpting

Body filler files and rasps sandpaper all made this possible.

The use of a sharpie was great to draw in body lines to follow when carving out

Plenty of carving and refilling with expanding foam

Step 5: Cover for Fibreglass

Cover with tape or latex paint with a roller then you can proceed with laying up your fibreglass

I used 3M tape for my project

As a first coat used a thick fleecy fabric to get a good even layer and to get body lines glued in certain spots

for glueing the fabric to the form I used 3M supper 77 spray adhesive

At this point after laying up my Fiberglas I attached the form to a plastic bumper half with screws and fiberglas strand from a can, sanded it up and layer another layer of glued fabric to cover the whole bumper on the car

Adding a bumper from the car your making is allot easier than trying to make sections around headlights, grills and tabs to attach to the fenders. I picked up a broken bumper from the scrap yard for 30 bucks

Step 6: Sanding and Getting Ready for Final

The use of short strand fibreglass putty and some sanding I was able to get closer to my goal

Additional expanding foam was needed for a section

Unfortunately I had to get rid of the car so never got past the point of the end of this instructable. Hope this inspired others to follow an idea !