Bondo usage

Gantt

Member
Hello, I have a 46 2N that has a small rust hole in the hood. I ll try to get a picture tomorrow evening after work as it s dark outside now. The hole is on the left side front, where the molding is. The hole is about 1 1/2 inch wide and 4 inches long. Due to the place, cutting out and welding in a new piece of steel is not really ideal.


I ve never used body filler as it s much better to replace the panel. Does anyone have any advice for this type of repair? I am a mechanic with good ability with my hands but zero body experience.
 
Rough fill the hole in with "bondo-glass" fiberglass reinforced body filler and finish it with the regular bondo. Make sure all rust and
paint is ground away first. Works for me hope it helps.
 
To each his own, but there's no substitute for cutting all of the rust out and welding new metal in.

You might think you have all of the rust ground out, but it will always come back. Over the bench in my shop I still have a lump of Bondo with some screen embedded in it larger than one of my fists. I dug it out of the cab corner of a Chevy pickup.

When I had a full time body shop, my main competitor in town was nicknamed "Bondo Bill" because all he ever did was slop Bondo on top of rust, or at most braze junk tin in the hole before filling it with Bondo. (Bronze is one of the few surfaces Bondo won't adhere to). I made good money just redoing his botched up jobs.

In fact, you could see the parking lot in front of his shop from my office window. I was talking with a customer one day when a semi pulled into the parking lot in front of Bill's shop. My customer commented, "Looks like Bill is getting another shipment of Bondo".
 
I've restored a few first gen Camaro's years ago with my dad. we never allowed bondo to be used, always repaired or replaced the panel.
on this tractor, i am on a budget. i see new hoods for sale but i dont like the fact that the air cleaner door is there. was not on the original 2n... I'm not looking for a show quality job, i just want a clean example. sort of like a clean daily driver vs a show winner. you cant drive a show winner without worrying about someone rubbing their shoe across the sill plate. i wish the hole was in a flat section, but it appears rust always finds the worst spot to repair and digs in deep.
I'll be moving the tractor into my shop after work today so I'll snap a picture of the rust hole.

I'm going to give the filler a try.. Mainly i didn't want to guess as to what kind to buy. thanks for the replies. always nice to get others opinions and experiences
 

I am not saying that you need to get really fussy with it, but if you leave a hole in the metal there will be rust working under your filler before you can even get paint on it. If you leave rust under the filler it will be expanding before you get paint on it. At least use rust converter to kill the rust in the pits. I am no tin knocker but I had to repair some spots like the one you describe on a car two years ago. All I used was a pair of bending pliers, a vise and hammer and dolly to put the style lines into 20 gauge steel. An auto body friend painted the sheet metal on a tractor for me ten years ago. He took it down to bare metal but didn't use rust converter. There were two areas with rust pits, and the paint there bubbled up in just two years.
 
you know, i think i'll try to recreate the section. all i can do is waste time trying, or it will work. no reason not to try. i work at a Mack Truck dealership and our body shop has all kinds of salvage sheet metal laying around. would not hurt to try and see how well i can match the body lines.
i know if i go the bondo route, its only kicking the can down the road... and not very far at that. i am very savvy mechanically but body work is new to me, i guess i have gotten used to knowing what i was doing with mechanical parts for so long i have gotten lazy about learning new stuff.
 
One of you guys just said bondo wont stick to bronze. Does this mean it wont
stick to Brazing??

I have a spot on my 860 that was repaired with braze. It still needs some shaping.
Will bondo stick to the braze??
If not, what can I use?
 
(quoted from post at 15:51:12 01/11/20) One of you guys just said bondo wont stick to bronze. Does this mean it wont
stick to Brazing??

I have a spot on my 860 that was repaired with braze. It still needs some shaping.
Will bondo stick to the braze??
If not, what can I use?

There is no reason that it would not stick. The bond is mechanical not chemical. Just make sure that it is not glassy smooth or dirty.
 
(quoted from post at 08:38:45 01/07/20) you know, i think i'll try to recreate the section. all i can do is waste time trying, or it will work. no reason not to try. i work at a Mack Truck dealership and our body shop has all kinds of salvage sheet metal laying around. would not hurt to try and see how well i can match the body lines.
i know if i go the bondo route, its only kicking the can down the road... and not very far at that. i am very savvy mechanically but body work is new to me, i guess i have gotten used to knowing what i was doing with mechanical parts for so long i have gotten lazy about learning new stuff.

Good for you Gantt!! Can do attitude. I assume that you will be MIG welding it. Take it slow so that the metal doesn't heat up and distort, especially at the corners.
 
regular body filler does not like to stick to brazing. we use a fiberglass reinforced filler first, then finish with regular filler. also works good over a leaded seam. usually encounter this when doing a restoration and in the sail panel- quarter panel seam, or upper rear body panel to quarter panel. heres a link to the 3m stuff.
poke here
 

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