Silver Spring, MD 20906 (301) 364-4619

How the Professionals Repair Bodywork

How the Professionals Repair Bodywork  

What Are Auto Body Repair Fillers?

When it comes to auto body repair, body fillers are materials which use a catalyst in order to harden. Anyone that has ever mixed a batch up will know this all too well, however, not many know that the red or sometimes the blue catalyst is MEK peroxide. The “MEK” is short for methyl ethyl ketone, which is an aromatic chemical compound which can be extremely hazardous to one’s health, which is why it comes with warnings on the labels which tell you to use the materials only in ventilated areas or by using a respirator.

The filler is a complex mixture of material which contains, among other things, resin, talc, and fiberglass. The resin will allow for adhesion, and the talc, and yes we do mean talcum powder, makes the material flow smoother. This is because talc is hygroscopic, meaning it absorbs moisture, unfortunately, it is also the reason fillers will absorb water. The main solvent in filler is styrene, this vaporizes as the mixture starts to cure. Bubbles in the filler will occur when the mixture dries too fast, as it traps the styrene gas.

Body fillers are actually thermal-set plastics. Meaning, they will dry with heat, which is created by a chemical reaction between the filler and catalyst, and become hard and stable, often within a matter of minutes. However, too much hardener will mean the cured material will become too brittle and crack, and too little will mean it will never dry.

Temperature is also extremely important for exothermic, which is a fancy but scientific name for catalyst-induced heat reactions. In point of fact, curing can be drastically slowed below 64 degrees F ambient air temperature, meaning it can often take literally days to cure. The best temperature when it comes to using filler is anywhere from 70 to 80 degrees F, and this includes the metal you are applying the filler on!

Well there you have it, auto body repair filler explained in layman’s terms. For information on our body repair services, call us at A & S Auto Service Center - Silver Spring today at (301) 364-4619, we are based in the Silver Spring, MD area.

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