When it comes to car body work, having the right filler is crucial for achieving professional-looking results. As a DIYer, you want a filler that goes on smoothly, sands easily, and provides strong adhesion. With so many fillers on the market, it can be tricky to determine which is the best choice for your auto body repair project. This article will examine the most popular DIY car body fillers and provide recommendations to help you select the right product.
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What to Look for in a DIY Car Body Filler
Here are some key factors to consider when choosing a DIY car body filler:
- Easy to mix and apply – You want a filler that mixes smoothly without clumping and applies evenly without dragging.
- Good adhesion – It should bond tightly to metal, fiberglass, wood, and plastic surfaces for a durable repair.
- Easy to sand – The cured filler should sand smoothly without gouging or gumming up sandpaper.
- Short cure time – A filler with a quick cure allows you to move through projects faster.
- Strong and rigid – The repaired area needs to be left durable and hard after curing.
- Minimal shrinkage – Shrinking as it dries results in low spots and potential cracking.
- Resistance to chemicals – It should hold up well to solvents, acids, and road debris.
Along with performance, also consider price and availability when choosing a DIY body filler. Ideally you want an affordable product that is easy to purchase locally or online.
Top DIY Car Body Fillers
Here are some of the leading DIY auto body fillers to consider for your project:
Bondo All-Purpose Body Filler
Bondo is one of the most recognized names in auto body filler. Their all-purpose formula has proven itself over many years as a reliable performer. It offers:
- Creamy formula spreads easily
- Adheres well to different surfaces
- Cures fully in about 20 minutes
- Sands smooth with no pinholes
- Extracts easily with minimal effort
This filler from Bondo is an excellent general use option suitable for metal, fiberglass, concrete, wood, and other surfaces. It dries hard enough for most repairs while still being easy to sand. For small repairs on thin panels, a glazing putty may be a better choice to prevent sinkage.
3M Bondo Body Filler
As another leading brand, 3M Bondo makes a lightweight body filler that works well for DIY use. Benefits include:
- Light cream color for easy spreading
- Featheredges smoothly
- Minimal pinholes in finished product
- Cures quickly in 15 minutes
- Easy to sand and shape
This 3M filler features a lightweight formula designed for easy sanding with reduced effort. It offers strong adhesion and fills dents easily without sagging. The fast 15 minute cure time allows projects to be completed quickly.
Evercoat Rage Ultra Premium Filler
For a high-quality DIY body filler, Evercoat Rage is an excellent premium option. It provides:
- Super smooth spreads easily
- Cures in just 10-15 minutes
- Minimal shrinkage for a long lasting repair
- Stays flexible to resist cracking
- Does not dry out when left open
This professional quality filler glides on easily without drag or pull. It cures fast for a quick project turnaround time. The flexibility helps prevent cracks from forming over time. Evercoat Rage works well on metal, fiberglass, SMC, wood, and other substrates.
USC Icing Body Filler
For a great value, USC Icing is tough to beat. It provides:
- Smooth cream formula
- Good adhesion to different materials
- Dries hard to resist impacts
- Easy to sand into shape
- Won’t soften from exposure to sunlight
This affordable filler sands quickly with very little effort for efficiency during bodywork. It is compatible with all types of primers and paints. USC Icing works well for overall auto body repair and restoration projects.
Key Factors in Choosing a Car Body Filler
With an overview of top options, here are some key considerations when selecting a DIY car body filler for your project:
Type of Repair
The right filler depends on the specifics of your repair. For metal panels, an all-purpose filler like Bondo is ideal. On plastic or fiberglass, a specialty filler formulated for composites will provide better adhesion. Glazing putties are best for minor repairs like small dents and scratches.
Performance
Look for a filler that spreads smoothly without too much effort. It should cure uniformly without shrinking or sagging. The cured filler should be rigid but not brittle. Always test sand a small area to ensure it sands cleanly before applying it widely.
Ease of Use
Consider how much sanding will be required after applying the filler. Some formulas sand much easier than others. Also look for quick cure times to help projects move faster. If you’ll be using the filler over an extended period, check that it does not dry out or harden when left open.
Adhesion
Ensure the filler will bond tightly to the repair surface. Some formulas grip metal better than fiberglass or plastics. Extra prep like scuffing the area may be needed for optimal adhesion.
Price
Filler cost can range from $10 per gallon up to $50. While premium fillers provide excellent results, cheaper options can also work well when applied properly. Factor in how much you need for the project scale.
Tips for Applying DIY Car Body Filler
Once you’ve selected the right filler, proper technique is also key for achieving quality results. Here are some tips:
- Thoroughly clean, dry, and scuff the repair area first
- Use painter’s tape to mask off surrounding surfaces
- Follow exact mixing instructions for hardener amounts
- Only mix up as much filler as you can use in 3-5 minutes
- Apply in thin, uniform coats for the smoothest results
- Avoid thick coats which can sag, shrink, and crack
- Let filler fully cure before sanding, usually 15-30 minutes
- Start with coarser 80-100 grit sandpaper and work up to 220+ grit
- Be sure to wear a respirator mask to avoid breathing dust
Proper preparation, mixing, application, and sanding are all key for achieving professional filler results. Test first on scrap pieces to dial in the method before tackling visible repairs.
Prepping Areas for Filler
To ensure the filler bonds tightly, always start by properly cleaning and scuffing the repair area. Here’s how:
- Clean with soap and water, then wipe with a grease remover
- Sand area with 80 grit sandpaper to scuff the surface
- Blow away or vacuum all dust after scuffing
- Wipe with a tack cloth for maximum adhesion
Any contaminants left on the surface can prevent the filler from gripping tightly. A thorough prep process removes grease, rust, and dust. This allows the filler to penetrate for superior adhesion.
DIY Car Body Filler Recipe
For ultimate control and cost savings, some DIYers make their own body filler recipe. A basic formula is:
Ingredients
- 2 parts polyester resin
- 3 parts fine silica talc
- Catalyst paste or drops as directed
Directions
- Mix measured amount of resin first
- Gradually stir in talc powder until smooth
- Add catalyst and stir thoroughly
- Apply mixture within 3-5 minutes
This simple filler can be customized as needed. More talc makes a thicker filler best for deeper repairs. Less talc allows better spreading for skim coats. Other additives like microballoons can be used to alter drying properties. Test small batches first to dial in the ideal homemade filler recipe.
Types of Car Body Fillers
There are several specialized filler formulas designed for certain repair scenarios:
| Filler Type | Description | Best Uses |
|---|---|---|
| Polyester Filler | Two-part polyester resin and hardener, all-purpose | General metal repairs |
| Epoxy Filler | Two-part epoxy for superior adhesion | Metal, plastics, composites |
| Aluminum Filler | Polyester filler formulated for aluminum | Aluminum and exotic metals |
| Glazing Putty | Softer paste filler for minor repairs | Small dents, scratches |
| Spot Putty | Thick filler for deep repairs | Deep dents, rust holes |
The product selection depends on the material being repaired, as well as the extent of damage. Most DIYers are best served starting with an all-purpose polyester filler which works for general repairs. Epoxy or aluminum-specific fillers can be used when required.
Car Body Filler Alternatives
While body filler is the go-to for many repairs, there are some alternatives to consider:
Fiberglass & Resin
On fiberglass vehicles, using polyester resin and fiberglass mat can repair damage effectively. This strengthens and layers the area for a lasting fix.
Metal Patch Panels
For rust holes and larger areas of damage, weld-in metal patch panels provide extra reinforcement. These bolted-on patches are seam sealed for durable rust protection.
Plastic Repair Epoxy
On damaged plastic bumpers, fenders, or panels, specialized two-part epoxy adhesives properly bond the plastic for lasting repairs.
There are also thinner polyester glaze coatings that can fill minor imperfections like scratches and dimples. While not a complete substitute, these alternatives complement body filler in certain applications.
Conclusion
From our overview, Bondo All-Purpose Body Filler stands out as an excellent overall choice for most DIY repairs. It spreads smoothly for quick and easy application, adheres tightly to different surfaces, cures rigid and hard for lasting repairs, and sands nicely into a feathered edge. For superior results, always properly prepare repair areas, apply filler carefully in thin coats, and sand with progressively finer grit.
With a quality filler and proper technique, you can repair imperfections, dents, rust, and damage yourself and save bodywork costs. Carefully following directions and safety precautions makes achieving professional-looking results possible.