Using Body Fillers Description and Application

History of fillers Lead was the filler of choice through the 1950’s The early 50’s seen the the first plastic body fillers developed made up of epoxy based materials 1955 seen the first polyester based plastic fillers, the same resin used in fibreglass fabrication, brittle and hard

History continued The first successful filler was named ‘Bondo’ thus the term used to describe the fillers we use today Makeup of the filler: 40% polyester resin 60% talc (by weight) These fillers were still hard to sand and produced a lot of dust

History continued Later technologies seen the introduction of finer grade talc's, and the introduction of hollow glass beads into the filler This made the fillers easier to sand, even after complete curing Other advancements seen different colours of fillers with different contrasting hardeners as well as ‘waterproof’ type materials for various applications

Fibreglass Reinforced Fillers Fibreglass body filler has fibreglass material added to it to aid in its strength Can be used in areas requiring extra rigidity Is also waterproof Can be used on steel and fibreglass substrates Used as a foundation under body fillers and over finished welds Excellent in high moisture exposure areas

Cream Hardeners Body fillers today are cured by using a cream hardener (catalyst) The active ingredient is benzyl peroxide combined with a plasticizer and a small amount of water Must be kneaded before each use Mix 2% hardener with body filler to cure Too much will cause pinholing, too little and it will not cure Hardeners come in multiple contrasting colours

Fibreglass Reinforced Fillers Two types available Long strand Higher strength, harder sanding Short strand Less strength, easier sanding

Aluminum Body Fillers As the name suggests, contains aluminum filings First introduced in 1965 Relatively expensive Waterproof Harder to sand, but finishes nicely Have the look of lead, thus more desirable for restoration

Lightweight Body Fillers Lighter in weight due to a reduction in talc (up to 50%) being replaced by hollow glass beads Used for final leveling of repaired sheet metal Homogenized 80% of shops today use this type of filler Will bond to galvanized and aluminum surfaces

Premium Body Fillers Higher quality ingredients, finer talc’s, smaller glass beads make up the difference Smoother creamier appearance Tack free Less likely to pinhole Easier to sand in some cases Non sagging

Polyester Finishing Putty Designed to replace one part spot putty, this fine grained material is excellent at filling minor surface imperfections Great dimensional stability Fine featheredging capabilities Can be applied over bare substrates, primers, or sound paint surfaces

Applying Body Filler Panel must be free of all rust, corrosion, oxidation, dirt and dust Free of waxes, grease and oils Water soluble, solvent soluble materials Filler application should not exceed 1/8” (3mm) to correct contour of panel All metal working operations must be of the highest quality

Application Tools Spreaders Two spreaders are generally used for mixing/spreading operation Correct size of applicator will aid in a successful application Must be cleaned promptly after use Made of plastic or metal

Application Tools Filler boards Made of plastic, metal or glass some are disposable Do not use cardboard Can absorb chemicals, and release fibres and waxes Board must be kept clean and smooth at all times

Prior to Application Double check all metal work for problems Mask any areas that may require protection (door gaps, mouldings etc) Blow the panel off one last time to remove any dust that may have settled on the panel

Mixing the Filler Do not intermix hardeners/fillers Mix only the amount of filler that can be reasonably applied at one time TemperatureWorking Time 100°F3-4 minutes 85°F4-5 minutes 77°F6-7 minutes 70°F8-9minutes

Mixing the Filler and Hardener A good R.O.T is one inch of hardener for every golf ball amount of filler Never stir the filler to mix! filler and hardener should be mixed together with a scraping/folding motion using a clean spreader and mixing board Stirring will introduce air into the filler increasing the risk of pinholing

Application to the Substrate Once mixed, use a clean spreader to apply the filler to the panel Choose the correct size of spreader for the task First application will require a firm, thin, tight spread of the material to work itself into the ‘tooth’ of the sanded substrate for mechanical adhesion Once this is accomplished, the filler can be applied for build, spreading the filler as smooth as possible so as to eliminate excessive sanding once the material has cured

After Application Immediately clean all application tools This requires the use of gun wash thinners to remove to remnants of the unused filler from the spreader/filler board. If there is excess filler, spread it onto a piece of paper towel to be dispose of in the garbage once cured Remember your safety equipment!

Sanding and Shaping Filler grating, otherwise called cheese grating, is performed with the filler in a semi-cured state Is used to rough shape a panel to help lessen the amount of sanding required to bring the panel into shape Care must be taken not to remove to much material at this stage, or you will be repeating steps previously taken!