| Thickness | Filler Volume |
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Estimating Body Filler
Body filler is sold by volume, but you think about a repair in terms of area and depth. This tool turns the size of your dent or rust repair into the volume of filler you need and the amount of cream hardener to mix with it, so you buy the right can and do not waste a half-cured batch.
Mixing the Hardener
The cream hardener is what triggers the cure, and the ratio is small, around two percent by volume. Mix thoroughly until the color is uniform with no streaks. Too much hardener cures the filler before you can spread it and can cause staining through the paint later; too little leaves it soft and gummy.
Thin Layers Win
Good bodywork builds filler in several thin coats rather than one deep slab. Thin layers cure evenly, sand flat more easily, and resist cracking. Deep fills over bare metal can trap moisture and fail, so heavy damage should be metalworked close to shape before filler goes on.
Frequently Asked Questions
How much hardener do I add?
About a two percent ratio, often shown as a ribbon of cream across the filler patty. Mix to a uniform color, and lean slightly less rather than more in cool weather.
How thick can I apply filler?
Keep it as thin as practical, generally no more than about a quarter inch. Deeper damage should be hammered or welded closer to shape first.
What is the working time?
Most fillers give a few minutes before they begin to set, depending on hardener amount and temperature. Mix only what you can spread in that window.