Expert: William Forster - 10/2/2007

Question
What criteria is used to decided whether to repair or replace a rear quater panel. If it is repaired using bondo, what are the possible long term effects? What would be the concerns paint fading, rusting, cracking of the paint??? What is the maximum thickness or recommended thickness of bondo?? is there a max area that should not be exceeded??

Thanks for you info

Regards

Richard

Answer
filler is the lesser of two evils when it comes to quarter replacement. If the dent is fairly minor, and there in no three dimensional damage such as damage to the trunk or door jambs, or any holes torn in it, then repair is in order. I personally hate to disturb factory seams and welds unless necessary. Filler shouldn't exceed 1/4 inch thick, it should be preferably about 1/8 inch thick. There are no paint concerns or rusting, or anything else like that. Filler has been around a good 35 or so years, and any body shop worth it's salt knows to use quality fillers. I personally have never worked in a shop that used bondo brand anything, it's an outdated product that needs an overhaul in it's design. Modern fillers are specialty fillers, designed to stick to aluminum, galvanized steel, paint, factory primers- whatever. What usually happens when filler fails, is there was a second impact to the previously damaged area. Filler tends to make the panel keep it's shape after it's been applied, but when it's impacted, it will crack if pushed in far enough. The fact is, the panel would have needed repaired either way- from a dent, or from a crack. I filled 2 massive dents in the quarters of my 66 GTO 17 years ago, about 3 feet by 4 feet, and they still look great. In the end, it's really up to the discretion of the estimator. I can't see your damage to make an assessment for you. Bill