How To Preserve Bondo Used In Car Repair

Plastic trunk filler – sometimes chosen putty, mud, or by its original brand proper noun Bondo – has been the filler selection since the 1960s. Information technology'southward commonly used when repairing vehicles after dents accept been removed, high spots reduced and imperfections eliminated. What remains is a straight simply uneven surface that must be smoothed out.

Epitome / AL THOMAS

Many companies manufacture torso filler nether several make names, but in general it is a two-office catalyzed body filler, the larger office existence the polyester rosins and the smaller tube beingness the catalyst (organic peroxide. Combining the two starts a chemic reaction to harden the substance. After application and hardening, information technology tin exist sanded to the proper profile, to provide an undetectable repair. Plastic body filler was designed every bit a convenient and less expensive culling to torso solder, which was used in the early on days of standoff repair. Body solder is more expensive and more hard to apply, but its main drawback is high toxicity. Atomic number 82-based torso solder posed toxic hazards for people and the environment.

Plastic body fillers are not without their own hazards, and technicians should read and follow the personal safety recommendations listed in the MSDS. Plastic torso fillers' fumes tin be quite toxic in high concentrations, and the hardener can cause burns with prolonged skin contact. Condom glasses, gloves and respirators all are recommended when mixing and applying body filler. During sanding, technicians should use proper personal protection equipment to avoid inhaling particulate matter (grit).

Although plastic body fillers were originally designed to be used to repair vehicles, they also have been adjusted for use in woodworking and other areas of repair where fillers are needed. In fact, at the 2022 Daytona 500, officials patched a pothole in the track using plastic body filler, which held upward for the remaining 40 laps before it was permanently repaired.

Plastic torso fillers come in different types. Fiberglass fillers are designed to repair large dents, rusted-out areas and tears or cracks in metal, fiberglass or wood. Their manufacturers claim this is a premium filler that is rustproof and waterproof. These fillers come with standard polyester rosins and fillers, only have strands of fiberglass reinforcement added for immovability and forcefulness. When the hardener is added and mixed thoroughly, the substance has a brusque period of fourth dimension when information technology remains pliable and can be spread in the area of repair. Following the cure fourth dimension, the substance hardens and can exist sanded to the proper contour for a durable repair.

Other products are marketed as lite trunk filler, which comes without fiberglass and is more commonly used to repair the dented areas that take been metal finished and brought dorsum to their original shape and state. Then a small-scale layer of plastic trunk filler is used to smooth out the surface.

Polyester glazing trunk fillers are for those times when a lite, smooth and durable glaze is needed for finish work. Some body technicians prefer to use glazing chemical compound as an additive to light trunk filler, which thins it out and allows the technician to utilize a smoother and more precise final coat.

Surface preparation

Earlier plastic body filler can be applied following the dent repair, pigment must exist removed from the dented surface area using what is referred to as the "buff grind" method (Fig i). This is accomplished by holding the grinder every bit flat every bit possible, which speedily removes the paint from the high surface, revealing the low surface. Paint that remains in the lower areas can exist removed past holding the grinder at a higher angle. As shown in Effigy 2, the lower areas, which were ground at a college angle, reveal a dissimilar surface texture and appearance. Those areas can now be raised using a weld-on pulling tool such as seen in Effigy three, and a pick hammer; or a hammer and dolly method can be used, if access to the underside is available.

Image / AL THOMAS

Although some body fillers are marketed as direct-to-metal or corrosion-resistant, near recommendations by paint manufacturers suggest the application of a corrosion-resistant primer, such as acid etch or epoxy primer, to restore the corrosion resistance removed by grinding. Also remember that if the hammer and dolly method was used, the areas of impact on the underside of the console accept removed the corrosion protection materials due to the hammer bear on, resulting in what are known as corrosion hot spots. Treat all areas of potential corrosion earlier applying torso filler. A corrosion resistant primer tin exist applied using a foam brush or roller (Fig. 4) rather than spraying. The surface needed for application of body filler does not require the same smoothness as pigment; therefore, application with a roller, which is much quicker (Fig five) than the spray method, will be constructive.

Paradigm / AL THOMAS

The body surface area that has had the paint removed around the paring should exist feathered with a DA to create a smooth transition from the bare metal to the painted surface. Apply corrosion-resistant primer, covering bare metallic prior to the application of body filler. Past using a roller or castor, the corrosion-resistant primer can easily be reapplied after sanding the body filler if whatsoever breakthroughs occur.

Mixing

Plastic body filler, as the can lid indicates (Fig 6), should be mixed using a vertical-stir method (Fig 7). That is, the paint stick is pushed down from the top, continuing to the lesser, scraping frontward to the center of the can, and raised out. Then the can is turned slightly and the procedure is repeated until the entire tin is thoroughly mixed. Trunk filler can dry out quickly on the bottom of the tin can, or when the tin lid has non been replaced betwixt uses, every bit seen in Effigy 8. If this happens, products are available that can be added to remoisten the filler.

IMAGE / AL THOMAS

Most body fillers are catalyzed at a ten-ane ratio, which ways the torso filler rosins are (by volume) 10 times more than than the hardener. As seen in Effigy ix, a 4-inch broad pool of body filler is applied to a nonporous mixing surface and a full line of hardener is applied. Never apply cardboard because it soaks up the rosins and the goad, creating a poor mixture. The torso filler is and then mixed until all the streaks of color (hardener) are removed (Fig 10). Notice that the filler is being folded and pulled with downwards pressure level, kneading out the air bubbles (Fig 11). Never stir (Fig. 12), which increases the amount of air whipped into the filler, causing pinholes that will need to exist filled later.

IMAGE / AL THOMAS

Over-catalyzed filler (adding too much hardener) also will cause an backlog amount of pinholes because of the rut generated by the catalyst. A thorough application of body filler can be accomplished in one application. If the method outlined below is proficient, the technician can achieve body filler application with a single coat. This will increase productivity.

Some technicians mix standard light trunk filler with polyester glazing putty, usually in a ratio of 3 parts body filler to one part glazing putty (Fig 13). This thins out the body filler, and some techs experience that a smoother application of body filler can be accomplished. Also, the addition of glazing compound to slightly dried-out body filler can bring it dorsum to its original smoothness, aiding in the application of the filler.

Prototype / AL THOMAS

Torso filler separates easily during storage and should be thoroughly kneaded with your fingers (Fig fourteen) before using. If the tube is not kneaded properly, a sparse, watery, ineffective hardener volition come out. Body filler and hardener come in different colors (Fig 15) such as cherry, blue and white. In the by, the only deviation between these colors was the color. At present some manufacturers offering hardeners in three dissimilar hardening speeds for common cold, medium and hot weather. As ambient temperature rises, the catalyzing process is speeded up. So often, in very hot weather, when plastic body filler is mixed, it will harden so rapidly that a smooth application is impossible. An alternative is to add the hardener beside the filler, walk to the vehicle, mix and apply, usually in minor batches.

Awarding

After the surface has been properly prepared and the torso filler mixed, application is critical. First, a very thin coat of body filler is spread over the unabridged prepared area (Fig 16). This wets the surface so a thicker glaze can be immediately practical over that wetted surface (Fig 17). After several thinner coats have been applied to the surface area to exist filled and the surface of the body filler is as thick as necessary (never to exceed i/4 inch, with one/8 inch preferred), the edges are feathered (Fig xviii) to facilitate sanding. Notice in Figure 18 that the lower edges are smoothly feathered, and a second pass will be drawn across the top to feather it too. The smoother the application of torso filler, the quicker the sanding will be completed.

Paradigm / AL THOMAS

Sanding/smoothing

Sanding or smoothing the surface of the torso filler is accomplished by using a block and sandpaper, commonly starting with P80 grit sandpaper. When body filler is practical and hardening takes identify, the surface may still feel a scrap oily to the bear on (Fig 19); and in fact this mucilaginous surface will quickly load your sandpaper. Often body techs will proceed a piece of used P80 grit paper on mitt to be used with this first sanding application, instead of sacrificing a new piece. Later the initial sanding to remove the sticky surface, apply a guide coat to reveal high and low spots. Although a guide coat (Fig 20) is most oft used when block sanding primer, it as well is an first-class help when sanding plastic torso filler. A vacuum sander helps remove the debris, which can exist significant when sanding plastic body filler.

Afterwards the body filler has been sanded smooth and apartment, use a DA with P80 grit sandpaper to plume the surface. A guide coat is applied prior to using a DA sander, which helps reveal high and depression spots and indicates when to stop sanding. With the assist of guide coats and connected sanding to the appropriate grit for priming (some companies recommend P220 or P320), this process is designed to remove any linear scratches produced by the cake sanding or swirl scratches produced by the fibroid DA sanding.

When information technology seems that the surface is completely prepared for priming, the technician should experience the surface to make sure no imperfections remain. To help with this process, a slice of cloth or newspaper can be placed between the surface and the technician's mitt to aid in feeling for imperfections. Note that the technician is using his left mitt, his non-dominant hand, which helps to experience the imperfections more than readily.

Post-obit cleaning (both with compressed air to remove the dust and a concluding cleaning to make sure no contaminants are on the surface), the repaired expanse is ready for priming.

If the tools that you're using are cleaned, maintained and stored properly, they will last for years – perchance your entire career. To go along your tools in good operating condition, air blow and wipe them clean, oil them and store them properly.

If the filler is mixed properly, to the right consistency, using the proper amount of catalyst, it can be applied rapidly and smoothly with a single application. Pinholes can be kept to a minimum if the proper amount of goad is used, and by mixing or kneading correctly to remove the air.

Often new technicians do not realize when information technology is fourth dimension to terminate sanding and to apply another coat of plastic. By using a guide glaze to help visualize the removal of scratches and low spots, and by using a trapped fabric betwixt your not-dominant hand and the surface, it's easier to recognize when you should finish sanding. Learning how to apply plastic trunk filler properly, with do, can go on the sanding to a minimum and assistance speed up the repairs.