The Stovebolt Site Forums The Shop Area Paint and Body Shop Dent repair, bondo question from bodywork newbie

Folks -

I'm new to the finer points of bodywork, and am looking for advice. We have a 47 1 ton, and a tree fell on the cab late last year. The roof was banged up pretty badly, but it can be repaired.

A bodyman, friend of my Father in Law's says that when we are done taking care of the dents, that the entire roof section should have a light coat of bondo. He says that the expansion and contraction rates of metal vs bondo will make spot patching on the dented area (a fair sized dent, to be sure) show, where as if the entire roof has a thin coat and the dent is repaired in the normal manner, it will last much longer and look better.

I can understand about sun heat and metal vs bondo expansion, I just thought that all things equal, less plastic is better. After bumping things out yesterday, it looks like the deepest flaw would need 1/8 to 1/4" of filler, if we don't do more work.

I would appreciate the feedback of those with more experience. The fellow works quickly and seems to know his stuff, so I guess I am just looking for a second or third opinion...

TIA,

John

You'll want to get it so that you won't have any spots of filler thicker than 1/8". 1/4" thick is too much, and will most likely crack. I do beleive your father in laws freind is on the right track, that's how I've seen it done on some of the assorted shows on TV. I would suggest popping for the pro-grade fillers, like Dyna-Tron or Evercoat, rather than the regular Bondo. You'll get better results and they seem to be easier to work with.

Longbox55 is correct, 1/4 inch filler is too thick. I see no reason to cover the entire roof with filler. I used to be a bodyman & still am in & out of body shops every day. No one I know covers an entire panel because of expansion or any other reason.

I say longbox55 is right I also have done body/paint for 35 years and never saw a need to coat the whole panel try your best to remove as much of the dent as you can and don't use primer to do any filling that will also fail on a hot roof if its to thick good luck

It's less the expansion/contraction differences between body plastic and metal than it is the difficulty in working a flat panel. A flat panel like a hood or roof has little strength so sanding & feathering a small spot is more difficult. I personally was never a fan of putting plastic on large areas but that seems to be accepted practice these days. If the prep is good, quality products used and thickness kept to less than 1/4" you'll probably be OK with the skim coat.

Knedert, I'm a neighbor of yours right here in Sonoma County. Before you start slathering bondo onto a nice Stovebolt, you might have a look at my '36 pickup restored by an amateur (me) without any bondo.

We motivated amateurs can often do better tnan the "pros" because we're willing to put in the time to do the job right rather than "quick and dirty" to improve the bottom line. All bondo does is fill dents, it does not remove them.

For camparison I also have a '78 El Camino worked on by a "professional" body shop for the previous owner. It looks OK but it was obviously not block sanded and the difference with the home straightened and painted '36 is very obvious.

I agree with all the answers from everybody. We never have bondo greater than 1/8" thick, it will crack. Preferably you want the filler as thin as possible. You need to spend more time straightening the metal, pick and file, hammer and dolly, heat shrinking etc. This takes a lot of time, that production body shops won't take that amount of time because it cuts into their profit margin. As a hobbyist with body work experience we can take as long as it takes to get the panels straight. Then a minimum skim coat of filler and the proper block sanding technique will assure that everything is straight. I am partial to Evercoat brand "Z-Grip" or "Rage" fillers. They sand easy, have no pin holes ( provided you mix the filler and hardener correctly) and don't shrink or stain thru the primer and finish base coat/clear coat paint.

Very good discussion going on here. So I'll throw in 2 cents more from another body work newbie. Armed with a little knowledge, a 3 pound ball peen hammer, and a grinder a novice metal shaper can do a lot of terrible damage. I learned that the hard way.

On the other hand bringing a light body hammer and proper dollies with some information from u tube or a basic metal shaping DVD and a lot of patience some really nice work can be accomplished.

"On the other hand bringing a light body hammer and proper dollies with some information from u tube or a basic metal shaping DVD and a lot of patience some really nice work can be accomplished."

You are so right Eileen. And I would like to tell you from personal experience that NOTHING comes close to the personal satisfaction that results from competing against and beating at the national level extremely expensive "professional" restorations with a home done restoration that cost the do it yourselfer only time and materials.

I have no exceptional skills. However in the early 1970s when I restored my '36 Chevy pickup I had lots of knowledgable people giving me encouragement, saying "You can do it".

The best incentive I can think of to do really good metal finishing work is to use lead, not Bondo for the final finish. When it's necessary to use a torch and a hardwood paddle to spread the filler, you won't be using any more than necessary!
Jerry

If you do lead do not let any kids in the area. Hose shop down top to bottom when done. NO compressed air or household vacs. I did field evals on lead work in a shipyard. One day burning thru lead bearing paint put a guy over limit - was astounded.

If you want a surprise get a blood lead before and after you are done.

Dan Bentler

Good input Dan. When I first got into body work lead was just being phased out by body plastic. A lot of the "old timers" still used lead. I put "old timers" in quotes because most were in their 40s & 50s but looked 90.

Dan and Tiny the actual health hazards of substances like lead and asbestos are vastly overstated by the environmental clean up industry. That type of stuff occurrs naturally. For example natural arsenic and asbestos commonly occur in bedrock and groundwater and there is even an acronym for it; naturally occurring asbestos minerals (NOAMS). I know because I'm a geologist and hear this fear mongering all the time.

It takes long term exposure for adults to get health effects and the effects don't show up until decades after the exposure. So for us baldies and gray heads the subject is academic. Something else will get us before the lead and asbestos, etc do.

A yuppie texting or yapping on a cell phone will probably T-bone us in an intersection while we're shopping for lead for body repair or an asbestos clutch disc or brake shoes/pads.

Let's enjoy our hobby.

Good point, Yar! Just mention evil lead and the Kool-aid drinkers come out of the woodwork with their tar, feathers, and pitchforks! I smelt several hundred pounds of lead, mostly old wheelweights, every year for bullet casting, and I've managed to survive to the ripe old age of 65 with no apparent ill effects. (other than having a low tolerance for fools!) A reasonable amount of ventilation and some common sense goes a long way toward minimizing a lot of workplace hazards. Now, my first full-time job, working in a battery factory where they took absolutely no lead exposure precautions- - - -that probably got me more heavy metal exposure than the rest of the 40-something years of my automotive and industrial career combined!
Jerry

You will be surprised what a little dry ice will do for small, shallow dings or dimples.

My neighbor does it all the time. It really works!