Hey all, I am working on a 41 Chevy Business Coupe. I am a novice when it comes to body work and I want to make sure I set myself up for success. The car is still in black primer and it's not going to be a show car. It's going to get another coat of matte black primer when it's "done". The door bottoms (inner and outer) are rusted out. I have new patch panels ready, so today I took on the Drivers Side and cut off the bottom 4 inches of both bottoms. Being an 80 year old car I planned on encountering a skim coat or two of bondo on the original doors. However what I found was a solid quarter inch of bondo. What's the best course of action? - Sand down all the bondo and see what I have? - Buy re-pop doors (don't really want to do this haha) - Sand down a bit of primer from where I am welding in the new bottoms and just weld them in? - Something else I am missing? I added a couple pics to show what I am trying to say haha.
Start working your way up till you don’t find anymore bondo, compare with your patch panels and that should give you an idea of you need to replace the doors
There are no repop doors available so that's not an option. I'd strip all of the body filler off of that door before I welded my new bottom in. Even if it weren't that thick, the heat from the welding is going to loosen/soften the filler and will fail much sooner. If the door is pushed in slightly, you can brace it out a bit more while welding the new bottom on, to get closer to level, so when you're done you won't need as much filler. Filler looks like 3/16" thick, from your pic the 1/4" measurement is including the steel. 3/16" is more than it should be, but it's not horrifyingly bad. I'd be more concerned as to what else is hiding under body work on that car, considering how terrible that cut off door bottom looks.
Remove the filler and find out what’s going on. Then go from there I will straighten metal before welding patch panels. This means any distortion that happens after the welding is attributed to the welding. Makes removing weld distortion easier.
Can I also make a suggestion? Even if you're going to end up replacing the whole bottom of the door, dont' cut the whole bottom off at once. If there's anything left of the outer skin, even if it's all mud and rust, I personally like to take just the inner section out, leaving the remnants of the outer skin in place to help line up the new panel. Sometimes that requires cutting off the overlap around the bottom and up the sides to get the inner section out. But that way you have a good reference as to where the inner bottom section should land, trim to fit and weld into place, then cut the bottom of the outer skin off and match it up to the new inner. When you cut the whole bottom off, all you have to rely on is measurements to know how far down the door is supposed to go. Can make it tough to get good body gaps.
In the world of BONDO, the bigger the glob, the better the job, does not apply. I concur with - anthony myrick - 1/4 inch of a layer of bondo is maximum thickness recommended.
You will probably have good metal above the Chrome line, just kidding but do get to bare metal even if you have to go up a foot. Usually in my experience 6 to 8 inches from bottom is the worse it gets. By then you start having something to work with.
Sometime for a door bottom, I’ll strip the door. Align the door and lay out scribe lines away from the rusted area. I’ll take measurements for door gaps off the scribe lines. I can add or subtract to get the size gap needed. Remove the door and use the scribe lines as a reference to build the door off the car.
I've been in that position many time's, what I do is remove everything from the door and start fresh. Body damage is other parts of the door skin can effect your welding a patch in. I would go over the door straitning the panel the best I could. Prep the door for welding, take your time and you won't have a mess to cover up like the last guy....
go around car and do some cutting in various spots with fiber grinding wheel and find out how much "mud" is hidden under that matte black primer - go under car & examine frame, bushings, etc - best to find out what you really have now
That much bondo calls for serious investigation of the rest of the vehicle, little story from 1980 when I was apprenticing, car shows up in the yard, early 60s t bird, pale yellow and black vinyl roof, full load/ black leather interior. Me and my buddy are goggling over this car when the boss shows up, says we’re to paint this car black but first it’s getting sand blasted, well we’re confused as hell so ask why, he shows us a couple odd looking cracks around the rear window, which we had not noticed. Next day a mobile sand blaster shows up and starts in, didn’t take long to find the sin, up too an inch of bondo around the back window, then the brass and rivets and wire mesh started showing, two cars cobbled together. Owner shows up a couple hours later, first time I see a grown man cry.
Option 1 .Take your shirt off, get a bottle of night train and go sit in the corner and cry . Option 2. Patch what you have cut already , spread another layer of Bondo over this layer, paint it and don’t t speak of it again. Option 3. Strip the car to metal , asses the situation and repair accordingly. I had a slightly O/T 69 Lincoln that had about 2 lbs of bondo in one rear door that had a dent in it , the rest of the car was pristine. I sandblasted the door and in about 1/2 a day had the panel back how it left the factory. For some people I think 1/2-Assery is a level of perfection they strive for.
That may be the case and I am no professional panel beater but i like to stay with a skim coat of filler. Nothing more than about a 1/32nd of an inch is what I feel comfortable with.
Grind out the bondo. Mount the door back on the car, making sure the gaps are good ALL around.. Line up the patch so it will align with the rockers on the body, and weld it in. Make sure you do a better job than the last guy who did bodywork there. If you have questions, it's usually best to ask before you leap. As was said above, not really smart to cut the whole bottom off the door at once.
Funny - I bought a OT B-body convertible that has a tail panel across the trunk. Spied the bondo between the trunk and where the back window would be and as I got in it for grins - just couldn't figure out why - as the rest of the body was pretty good. The day I took off the panel cover on the trunk - I found out it had a little rear end damage there on the trunk. Instead of making a adjustment on the trunk due to the rear bump - they just filled it in with bondo to make it even and got a new panel.
The quickest way to remove that much filler is to use a propane torch with a "fishtail" tip. To prevent overheating the metal keep the torch moving in a circular pattern, then once the bondo erupts into flame furiously scrape the melting plastic from the panel with a sturdy putty knife. Remember, avoid breathing the toxic fumes, wear closed-top shoes to prevent the flaming debris from setting your socks on fire, and above all, remember you have only yourself to blame for buying such a rusted-out bondo-buggy.
I thought my latest vehicle was bad. Generally, finding strata of Bondo is the best time to make sure there's none left before you begin. Even if that is the best way to apply a thick wedge of it (so each layer dries and hardens fully). (Map of the coast near Charleston) Any panel you've worked, beaten, heated that has Bondo on will begin to crack and delaminate. It won't last. New metal in, shaped as best as it can be, then a slim skim on top to take out the imperfections. Phil
jmo .41 chevys are out there . look a little save a lot . that door looks to me like it isnt worth saving . but i guess that depends on where you are heading with it . i see 2or three a month complete parts cars around n.ca so. or. a coupe listed now in cl portland or . $3500 the car looks to be very rough but comes with well over the asking price in newly plated parts . wish i could have found it before i had mine done . anyway just a example . partsare out there . but its all about your comfort level on the repair !
With that much Bondo I found that a putty knife or thin scraper, even a screwdriver, and a hammer are faster and keep the shop cleaner than using a grinder of some sort. when it’s thick like that, it peels right off in sheets once you get under it and pry. A grinder will fill your nose and lungs, as well as every horizontal surface in the shop, with fine filler dust. you’ll probably find a dent that has to be metal finished before you weld in your patches and door bottom. Don’t be discouraged. It’s all part of the hobby.
I'd start by using a grinder to grind off a channel in the filler starting at the cut, and working it up until you know where it ends. Then you'll have an idea at least of how much you've got to deal with. Since there are no doors, or door skins for a '41 Chevy, you're going to have to deal with the lower patch panels, and if they don't go up far enough, you'll likely need to patch in sheet metal to make up the difference. This is going to make the repair even trickier, as you'll have two joints to weld, so twice the chance of warping those big flat door skins! I had to do this on one of my '39 Chevy doors, as the patch panel was shy of getting to god steel. I cut more than I needed off, as I wanted a wider filler to control warping. I'm a beginner to major sheet metal repair also, so it was a learning process for me also. I had to tack it all together, and tack in my patch panel too. Then use a long straight edge to check for warping, and had to cut things loose occasionally to adjust the metal and get out issues. I've still got some filler in my doors once I finished, which a skilled metal worker would not have what mine has. But at least it's 1/8" or less and I'm OK with that. But I've got so many hours in my two doors replacing lowers that I lost track of how many days, let alone hours to fix them! A pro could have done the same in 10% of the time I took to do it!
Dust mask and wire wheel on your angle grinder makes short work of getting rid of the filler without damage.
Flap disk 80 grit 4.5 inch angle grinder, respirator. Once you see bare metal back off or you'll go right through...upside is you can strip an entire car in a half of a day by yourself
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