“Fergus” the Flat Fender spent his whole life on a cattle station, west of Broken Hill in NSW. Never registered for the road, he travelled 15,000 miles checking bores and other work on the property. I don’t know when he was parked up, but I guess he sat for 20-30 years in a shed. The red bulldust that had built up on all the hot parts had turned to a hardened, pottery like consistency and had cooked onto the surfaces. Screwdrivers and an old wood chisel removed the larger bits, but no amount of wire brushing would clean surfaces well enough to apply paint. As the engine/transmission/axles were going to be stripped and rebuilt, I abrasive blasted each as an assembly.
With the stripped chassis, complete with replaced back cross rail and front bumper, blasted and painted in a good quality black epoxy, the body tub was next in line. The way I attack rust in bodywork is to firstly abrasive blast back to good metal on the complete shell, then paint it with an oxide primer to prevent flash rust during the repairs. Fergus’ tub needed sections of the underside channels replaced, the drivers floor (RH side… he’s an Aussie) under the tool box, the toolbox assembly itself and a couple of patches on the outer skin. The rear of the tub was twisted and the floor was undulated over the cross-members, so I fabricated a framework out of a heavy wall, 2″ RHS and used a Porta-Power to get it back into shape.
Other modifications were, a built out section on the firewall to accept a pendulum pedal assembly (CJ7), and a removable panel centrally in the dash to accept a new instrument cluster. Next step was to apply a Polyurea elastomer coating to the underside of the tub with a top coat finish paint. Polyurea is an elastomeric, polyurethane that is applied at approx. 70-90 degrees and can be built up to thickness as required. Two or three passes of the spray will achieve at least 2mm film thickness. There are many brands of polyurethane elastomers (Line-X, etc) used for bed liners, but good quality Polyurea has a greater tensile strength and totally impervious to moisture egress. Rust pinholes in the LH floor and rear tub did not require to be welded or filled. Prior to coating application, masking tape is applied to the opposite side (interior) preventing bleed through, and when the interior is coated later, the bonding of the outer and inner liner will be stronger that the panel metal itself.
Our company, Glindemann Industrial Coatings Pty.Ltd. – T/A Glincoat, is in the business of coating application to concrete substrates in water infrastructure plants such as water treatment (read : poo-plants), reservoirs, and pond liners, along with mining equipment etc, for abrasion resistance.
Once the under side is done, the tub was flipped over to firstly straighten out the panel work with filler, spray putty and block sanding. The outer panels were then finish painted and masked off for the Polyurea application on the inside of the tub. As a final pass of the Polyurea spray, the gun is held away and a “mist” pass achieves the textured look to hide imperfections.