Body filler is an adhesive used to restore damage on vehicles by filling dents, creases and gouges with putty-like substances such as filler. When choosing body fillers it’s important to select the most appropriate product as not all are equal in terms of effectiveness.
Eastwood provides several reliable brands of body filler suitable for amateur use as well as professionals, from novice-friendly products to more robust professional grades. Be aware when applying fillers over weight-bearing areas or areas affected by rust.
Preparation
Body Filler combines a resin-based putty with a cream hardener to restore vehicle surfaces to their original state after minor damage. It is often used to repair dents and dings on car or truck exteriors and comes in various sizes and grades depending on what repairs need to be completed.
Before applying any type of filler, it’s essential that the area be free of debris. Surface should also be washed and dried prior to beginning any work on it. Roughening surfaces is also advised in order to help the filler adhere more securely, and primer must also be applied prior to any filler being used.
Once the primer has set, it’s time to prepare the damaged area for Body Filler. Surface should be ground back down to bare metal using water with your grinding tool to avoid overheating the metal and weakening it further. After which, 36 grit sandpaper on a dual action sander should be used extensively on that area for final sanding and finishing touches.
After mixing body filler with the appropriate ratio of hardener, the next step should be mixing it to make a cohesive final product. Care must always be taken when adding too much hardener as this could disrupt curing processes and result in cracking fillers that don’t cure properly. Sanding may also help smooth the filler and remove any bubbles or pockets which have formed.
If the area needing repair requires extensive work, one way to accelerate sanding is to sand body filler in its green state while still wet. Care should be taken as this technique requires waiting until body filler has set completely before proceeding further with sanding. Note also that older water-resistant primers weren’t effective enough at holding Body Filler securely against moisture reaching metal components which led to corrosion over time – an epoxy primer is therefore more recommended now.
Mixing
Standard body filler is one of several grades available and is often the go-to choice due to its ease of application and quick drying time (20-25 minutes). When treated properly, it sands easily to blend seamlessly into vehicle surfaces when treated appropriately; additionally it’s often available pre-mixed or sold individually as the least costly choice.
Before using body filler, it’s essential that the area needsing repair is cleaned and dried thoroughly in order to ensure an adhesion between putty or filler and its intended target surface. Staining of paint surfaces by body fillers must be avoided to minimize issues when refinishing, so using high quality fillers, mixing hardener correctly and working on dry days all help decrease their risk of staining.
When mixing filler and hardener, a clean mixing board is recommended for best results. Although some technicians might attempt to save time by mixing body filler directly on a vehicle where it will be applied, doing this may lead to mistakes that become evident upon sanding. Furthermore, non-cardboard mixing boards are the ideal choice since their absorbent properties could alter the chemical makeup of your mixture.
Finding the ideal ratio of body filler to hardener is vital; too much hardener could cause pinholes, while too little would not effectively filling dents, leading to weak repairs that crumble or flake when sanded.
Once the mixture has been properly blended, a thin coat of body filler should be spread over the area (Fig 16). This will wet the surface and allow a thicker application to follow more quickly. Multiple thin applications tend to work best as this allows the filler to flow and feather its edges, creating an undetectable repair.
Though some individuals may recommend specific mixing ratios, body shop professionals tend not to measure body filler; instead using the method outlined above. This approach can be more productive while simultaneously increasing quality in finished repair work.
Application
Body filler is composed of polyester resin combined with a cream hardener to form a putty-like substance used to restore minor damage on a vehicle body. Similar to spackle, body filler can help bring its smooth surface back after minor bumps and scrapes occur. There are three varieties of body fillers; choosing one depends on your desired results and type of repair job being conducted.
Step one in body filler application involves prepping the panel being worked on. A 36-grit to 180-grit rough surface should be prepared so the body filler will adhere securely, ensuring optimal paint adhesion and bond strength. After your surface has been prepared, measure out body filler and hardener carefully according to label instructions for best results. Too much filler will create brittle products that crack, while too little may not cure at all!
Once your product has been mixed, use proper lighting to inspect for pinholes and sand scratches, such as using a flashlight aimed directly across its surface. This allows you to see crevices or bases of pinholes more clearly while flashes of light can cast shadows that allow you to quickly determine what needs to be done to resolve issues quickly.
Depending on the type of body filler you use, adding talc (a powdered mineral) may also help it flow and sand more smoothly. Talc comes in various shapes and sizes; for best results it should be round.
Some body fillers are constructed from fiberglass-reinforced resin, making them stronger and more resistant to abrasions and moisture than standard body fillers. While more costly, they’re well worth their extra cost in terms of strength. Other body fillers feature high-tech resin that creates an extremely hard, solvent resistant finish; these latter options make an excellent choice when repairing large areas or striving to achieve high-quality finishes.
Finishing
Once body filler has set, it should be lightly sanded before spraying with high-grade automotive primer to prepare it for painting. A high-quality automotive primer serves as a surface upon which vehicle paint adheres more readily, creating long-term and visually appealing repairs. When working with body fillers it is important to adhere to best practices, as improper techniques could result in adhesion issues or other potential complications.
In order to properly apply filler, it’s crucial that your work area be well lit with plenty of ventilation. This will help avoid getting filler on your skin which could cause irritation as well as interfere with creating an even coat. Wear gloves while applying filler as this prevents oily hands transferring onto the work area and thus decreasing its effectiveness.
There are different grades of body filler available to meet your repair needs, from standard and medium grades through premium grades. These fillers range in thickness and viscosity to allow you the flexibility required for each task at hand. Standard grade body filler is lightweight and easy to spread; drying quickly to quickly address small imperfections or dents on surfaces without priming or painting needed; additionally it sands down easily for seamless surfaces after priming and painting processes have taken place.
Medium-grade body fillers are strengthened with fiberglass for increased strength and durability compared to their standard counterparts, making them suitable for use on metal and fiberglass surfaces. Medium-grade fillers can repair defects like scratches and defects as well as rust holes more effectively than their standard counterparts.
Premium body fillers are made from high-grade resins that boast superior viscosity for more reliable repairs. Ideal for larger areas that need repair, these fillers can be applied directly onto metal or over an epoxy primer for use as body filler products with the highest stain resistance and adhesion of all major filler products.
Selecting the ideal body filler is essential when completing any repair or restoration project, so if you need any guidance in selecting one for yourself or someone else’s project, don’t hesitate to get in touch with AutoZone’s team – they will assist in finding you just what you need along with all necessary tools and supplies!