ok car now drives great, started to repair and sand down paint, but down the sides of the car,door,front and rear fender I have found a thin amount of bondo shaping the lines of the car,also looks like the car have been painted twice i guess its not bad for being as old as it is, but is all that bondo ok? its about 1\16 or less thick. Thanks

Does it NEED bondo? Nope.

It will drive just fine w/o it.

That said, 1/16 is nothing.This is what came off my car...


That is over 3/8" of bondo...

I ended up putting a lot back in too. I should have just cut the panel off and welded in a new one. maybe the next time around.

Zach

On a professionally built car, there should be no bondo.

But hey, we are talking real world here (I'm assuming). Here is my two cents;

Before you started sanding, did you notice anything that would indicate that there was any problem? Was there cracking in the bondo. Was there any indication that the bondo wasn't adhering to the body surface below?

If you didn't know about it, then the bondo did it's job as intended!!!

When I get into a project car and discover bondo, I do try to figure out why it was there. I try to figure out how well it was done.

If there is any question, I sand it ALL off and re-do it if necessary. If I feel I can do the metal work better, then I do it.

There are two things you have to keep in mind.

Any filler added to the car (and that includes sprayed on fillers) will shrink over time. If you do bondo work, you should give it time to shrink before doing final shaping.

The other thing is that the quality of the finished paint job will be dictated by the quality of what is under it.

Wes

Hopefully the shaping is not a crutch to cover metal damage.

One of the saddest things I saw was a fully restored Mustang that was stripped to bare metal, painted, and buffed to a really high shine. When you looked down the side of the car, you could see a mark in the shine for every car door that had ever been opened against the car body.

My learnings? I bought a 2 foot long flexible blade (for spacking and wallpaper)that I use to swipe a very thin coating of bondo across the doors, sides, hoods, long fender areas of a car. If you are doing a door, most of the bondo wipes off , but it stays in those door dings to give you a smooth finish. Use the blade to check for smooth transitions from doors to fenders.

Ken

Bondo AKA body filler putty is an industry standard. it is not bad nor unprofessional to use it. 99% of all paint jobs will have it. of course, an inch thick is bad. if you want ZERO bondo, you are asking for "show quality " metal work. most people go into shock when they see the estimate of hours required to do a bondo free job. straightening most of a dent is also standard practice. the body filler is used to finish shaping, creating body lines and fillign in small irregularities. once metal has been bent or crincled, it stretches. the amount of labor required to get that last bit of bumpy-ness out is exponential to what it took to straighten the major portion of the dent

If not bondo I have seen lead. Still a filler.

Bondo is lighter and if you can get it in yellow it's Faster too.

Something else to consider, if you are trying to go full on CW.

The factory used body filler, and their paint had orange peel.

Zach

I agree with Wes in all but the first statement
"On a professionally built car, there should be no bondo"

A friend asked me to look at a truck his bodyman was working on. This guy was a bodyshop that was cheap. It was a 62 4x4 original chevy 1/2ton truck that was bought new by a rural firedept. it was really rough but lowmileage. The mexican bodyman had drilled or punched holes in the dents to either straighten them out some or to "hold" the filler in the very low places. These were dents that could be reached on the back side and inside the back of the cab. What was left were long worms hanging out on the inside of the cab. The truck was setting outside and the bare metal was rusting right up to the filler edge as he worked on other areas. He had already collected 3k from my friend and hadn't even used any primer. My friend is a civil engineer and not dumb but very tight on auto repair. I told him he was screwed and before he could get the truck removed his two parts trucks also dissappeared. There are all sorts of body shop techniques to fix dents and once the paint is on most people never know the real shape of the body underneath. If it's not a used car to sell and you intend to keep it a long time the less filler put on the correct way is the way to go. I've seen high dollar restoration shops put on new panels and still wipe the entire panel with filler to make it look perfect. Thin filler is almost a sure thing on any show finish. Most shops will not stand behind a paint job over other paint jobs. The thicker the paint the more apt it will be to crack in the future and you don't know if the old paint is adhered well enough to last the life of the new coat.

I REALLY cringe when I hear about stuff like this.

It brings up another thing about almost all bondo and fillers; THEY ARE POROUS!!

If you leave a car outside, water and oils can soak through the bondo and rust out the panel.

It's for this reason that if I am working on a "long term" project (and what 914 isn't "long term"), I seal the area with DDP DP epoxy primer. It's a "sealer"!

Wes

Done correctly filler is your friend. Just enough so everything is perfectly smooth. Allow to cure before painting. Paint needs to cure too. It doesn't happen over night.

Click to view attachment

I love looking at a freshly redone car on a rotisserie. I just hope the doorgaps are still good. Everything takes a set to a small degree.

Both doors on my '75 have been repaired with the punched hole/slide hammer method with evidence on the inside of the doors showing Bondo "worms." There is no visible evidence of cracking and shrinking on the outside paint. I will be repainting the car (not show/resto) and was wondering what's the best way to proceed. 1) Strip Bondo to metal to verify no rust, then re-Bondo. 2) Not worry about it, sand and primer, etc. (it's a SoCal car) 3) Strip Bondo and make an attempt to work the metal, however I can't get a dolly on the inside where the damage is mostly obsructed by the door brace. I have a stud gun so I can pull a little.

Andys

Small amounts of body filler are fine( not bondo! ) And don't forget they make a really awesome filling primer now. That will take all the tiny flaws out. Spray it on, sand most of it off.

Here's the Prelude project that's occuping my time while I wait for the paint to cure on the 914. Last weekend I sprayed the whole thing in the filler primer. I had already gone over the entire body to make it as straight as I could, but using this extra layer helps me get the final finish. It takes a lot more hours of sanding, but worth the effort.

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PanelBilly;

You are such a show off!

Wes

This week I layed off 4 employees because business is so slow. I need the sanding work to burn off the worries of the world. After a few hours of labor on the car, I'm too tired to even think about anything.

You got the money to pay for a bondo free car ??? Most people ( 99 % ) don't or won't. I will not give an estimate on a bondo free car. That is time and materials only. I don't think you guys have any idea what goes into getting a metal panel perfect without using bondo.

OK, the wording in that sentence wasn't all that good!! I guess it should say something like -- "in a perfect world, there should be no bondo".

I do know what it takes and I also know my limitations. That's why I buy bondo by the gallon.

Wes

[quote name='Wes V' date='Apr 3 2009, 05:51 PM' post='1153774']
--><div class='quotetop'>QUOTE(scotty b @ Apr 3 2009, 06:40 PM) </div><div class='quotemain'><!--quotec-->
[quote name='sean_v8_914' post='1153550' date='Apr 3 2009, 07:18 AM']
I agree with Wes in all but the first statement
"On a professionally built car, there should be no bondo"
[/quote]


You got the money to pay for a bondo free car ??? Most people ( 99 % ) don't or won't. I will not give an estimate on a bondo free car. That is time and materials only. I don't think you guys have any idea what goes into getting a metal panel perfect without using bondo.
[/quote]


OK, the wording in that sentence wasn't all that good!! I guess it should say something like -- "in a perfect world, there should be no bondo".

I do know what it takes and I also know my limitations. That's why I buy bondo by the gallon.

Wes
[/quote]


So how long do you need to have it "cure" before paint??

It depends on how "hot" it's mixed. If mixed real hot, it will do it's shrinking faster. The problem is that if you mix it too hot, it gets more brittle.


In my case, I tend to "block out" the shape and then go work on other items (after sealing it with epoxy primer). I don't worry about it for almost a month.

That's not a reasonable amount of time for a shop, but I tend to do do long term projects. So it's not an issue.

How important it is to wait depends on the thickness. The thicker it is, the more it will shrink. It's a percentage of thickness thing.

I'd like to hear Scotty's comment on this.

Wes

Lead...
My father inlaw insisted on lead only filler on his p1800ES.
I inspected the process at the hotrod shop nearby....it was lead only...and he paid for it.

I did tell him he was nuts.

RIch

They even have lead free lead now. Lead dust is very bad. Most of the lead repairs I have discovered had a skim coat of plastic filler over it.

When I went to body school, they told us to apply the filler, shape it before it dried all the way and sand after ten minutes or so. Get'r done style. This would be an accredited class to prepare you for a career.

Any time the body filler worms are on the inside of a door they will absorb moisture and the rust will start around the hole. It may take a long time depending on the humidity of the locale but it still happens. Now that the stud guns are available there is no excuse for open holes in panels. I've used my stud gun on everything even gas tank dents.

WOW, I never thought about this, but could see it happening.

Wes

Whats the thought on fiberglass filler on metal? better? worse?

Back in my high shool days (when dinosaurs roamed the earth), I was fortunate to have grown-up with a friend whose family had a body shop. I learned so much just hanging out and puttering with the cars I had back then. It wasn't till my fetish with 914s did I return to doing my own body work.

Although the body fillers and paint materials have greatly changed today, I really value learning some of the art of working out metal with hammers and body anvils. The body panels on a 914 are really just clay waiting to be remolded--it's amazing how close you can bring it back to stock without filler. I have no problem with a final leveling skim coat of filler and a lot of body blocking.

As far as those worm holes left behind from slide-hammers, if there is a backside that you can't treat, even welding the holes-up isn't going to help...might even make things worse if the worry is rust forming on the backside. You can always treat the worm hole with a small paint brush and a rust inhibitor. Pushing the brush through the hole allowing for the material to flow around the bristles will treat the back side. You'll need to re-prep the outer surface after things have dried before you lay any plastic down.

With our cars there are so may places you can't get to, the backside of those worm holes are probably the least of our worrries.

I agree the welding on the backside without being able to treat it is a big deal but you can usually blow sand in there to clean it and spray epoxy primer or cavity wax in to help it. Even using a stud gun burns the coating of the inside but it sure beats welding up holes. I punched my last hole to pull any body panels a long time ago. There are several fillers now that claim to be water proof but most of them are stranded and a little harder to wipe really smooth. Kitty Hare for one I think.