Rear quarter body help needed

[rod7515]

Working on my 66 Dart and as many know there are no complete quarters being repopped. The only thing available are patch panels. So I bought the wheel house panel and the lower rear panel. The method that we used was to glue them on to the body using the 3m 8115 bonding.
Once the 8115 was spread and the parts bonded together we used small sheet metal screws to pull it all together and tight. I left those in place for at least a month as I worked on other things. I removed the screws and tonight I welded the holes shut using an air hose to immediately cool the welds down. Here is where it looked like once welded and also you will see where the belt strip holes are welded shut as well.

So I guess its time to try to make this smooth looking and original.
Im moving forward on this on my own as the body guy that owes me money hasnt shown up in months to finish paying off his debt.
Heres my plan and feel free to throw ideas at me to move forward. I was going to use a thin layer of short strand fiber glass filler as the base. Once sanding it down go to standard filler. Now Im not the best at spreading filler and I dont seem to be able to get the filler as thin as I see them spreading it on TV. Ive been using evercoat rage 106. I have a reducer that Ive tried using that is called honey, not sure what the real name is but its supposed to thin the filler and it works but I didnt know how much i could use.
If you were doing this rear quarter work, once you got to this point how would you attack this? I think I will try to do what I have read about by trying a skim coat from the top body line above the gas cap down the entire quarter? Is this a good way to start?
Im no body guy so i need some guidance on how to move forward.
Thanks Rod

 

[GeorgeH]

I would have done it differently. I don't really know where to start. I'm not a big fan of panel adhesives because I've seen the stuff come loose over time. The heat from welding or grinding can loosen it up. I would clean that seem up best as possible and run tacks down it. It will weld like crap with the glue in there but it will weld nonetheless. Then grind seam and on to reinforced filler. Not talking bad about the bodyguy who did it, but if I was going to lap a panel in I would have tucked the replacement panel inside so the seam would have been a 1/2 inch down from the bodyline so that you don't have to "fake" the entire body line with plastic. He made you some additional work.

If the plan is to make the rocker/quarter seam along the bottom disappear I would tack that up too.

With plastic honey you can add a fair amount, but when it kicks it makes the filler harder to sand. You can add metal glaze to the mix also. 3M platinum plus filler is a lot smoother for finish work than rage.

 

[zkx14]

I would prime it and block to check for high spots. If you find any knock them down. If it's all close, might be able to just use glaze (thinner than filler). I wouldn't get hung up on trying to keep it super thin. Grater file will take it down quick.

 

[Bodyperson]

That sucks your body guy spleened out on you. We are a fickle bunch.
You should have just ground the heads off the lag screws and called it a day. No welding.
That being said, do not look at it as individual dents. Grind and fill the whole quarter panel with plastic filler.
It may seem absurd to you but that is how a professional would do it at this point.

 

[72bluNblu]

Oh boy. I don't even know where to start, so, I'll just start with the instructions for using 8115.

Here's some important excerpts from the 3m 8115 data sheet.

• When the manufacturer’s directions are followed, this product can be used to bond door skins, roof skins, quarter panels and box sides. In addition, product can be used for bumper cover repair under certain conditions. Typical substrates include cold roll steel, aluminum, SMC, and FRP. This product is not intended to bond structural components of a vehicle such pillars, rockers, or frame members. If doubt exists as to whether a particular component is structural, then that component should be welded.

• Quarter Panels: Adhesive should be applied to the lower edge, the wheel opening, the door jamb areas of the quarter, and at the factory seam of the sail panel. 3M suggests that the rear vertical portion of a quarter panel should be welded. It is acceptable to bond the rear vertical portion of a quarter panel, if recommended by the OEM. Additionally, most OEM’s only recommend full panel replacement. Should you perform a belt cut on a sail panel, 3M recommends welding the belt cut to ensure optimal cosmetic appearance. All areas to be welded should be sprayed with 3M™ Weld-Thru II (PN 05917). Do not apply adhesive to these areas.

​

• Caution: The adhesive is combustible. Keep any MIG welding a minimum of two inches from the adhesive. As with any welding operation, keep the appropriate fire extinguisher within reach, and be alert to any smoke or flame that may be present. Resistance spot welding through uncured adhesive is acceptable.

I attached the rest of the data sheet below. I think it's pretty clear. The 8115 panel bond isn't even recommended by the manufacturer for use on partial quarter replacements. On a unibody of this age, everything is structural, even the quarters. It's supposed to be clamped, not held in place with screws (no holes in the panels to fill). The panel bond is not supposed to be MIG welded, ever. The whole bit about induction welding only applies to uncured material, and they list a work time of 90 minutes and did all their testing after 7 days. So, a month later that's definitely cured, which means no welding of any kind.

As for the rest of it, fiberglass and metal don't mix. Ever. If you need a short strand fiberglass base under your body filler because it's going to be that thick you're sculpting, not doing body work.

How would I do it? I'd get out the cut off wheel and start over. The panel bond used was the wrong product for the job, and the installation so far goes against pretty much everything 3m says for using 8115. Panel bond has its place, this wasn't it.

 

[GeorgeH]

Oh boy. I don't even know where to start, so, I'll just start with the instructions for using 8115.

Here's some important excerpts from the 3m 8115 data sheet.

• When the manufacturer’s directions are followed, this product can be used to bond door skins, roof skins, quarter panels and box sides. In addition, product can be used for bumper cover repair under certain conditions. Typical substrates include cold roll steel, aluminum, SMC, and FRP. This product is not intended to bond structural components of a vehicle such pillars, rockers, or frame members. If doubt exists as to whether a particular component is structural, then that component should be welded.

• Quarter Panels: Adhesive should be applied to the lower edge, the wheel opening, the door jamb areas of the quarter, and at the factory seam of the sail panel. 3M suggests that the rear vertical portion of a quarter panel should be welded. It is acceptable to bond the rear vertical portion of a quarter panel, if recommended by the OEM. Additionally, most OEM’s only recommend full panel replacement. Should you perform a belt cut on a sail panel, 3M recommends welding the belt cut to ensure optimal cosmetic appearance. All areas to be welded should be sprayed with 3M™ Weld-Thru II (PN 05917). Do not apply adhesive to these areas.

​

• Caution: The adhesive is combustible. Keep any MIG welding a minimum of two inches from the adhesive. As with any welding operation, keep the appropriate fire extinguisher within reach, and be alert to any smoke or flame that may be present. Resistance spot welding through uncured adhesive is acceptable.

I attached the rest of the data sheet below. I think it's pretty clear. The 8115 panel bond isn't even recommended by the manufacturer for use on partial quarter replacements. On a unibody, everything is structural, even the quarters. It's supposed to be clamped, not held in place with screws. It's not supposed to be MIG welded, ever. The whole bit about induction welding only applies to uncured material, and they list a work time of 90 minutes and did all their testing after 7 days. So, a month later that's definitely cured, which means no welding of any kind.

As for the rest of it, fiberglass and metal don't mix. Ever. If you need a short strand fiberglass base under your body filler because it's going to be that thick you're sculpting, not doing body work.

How would I do it? I'd get out the cut off wheel and start over. The panel bond used was the wrong product for the job, and the installation so far goes against pretty much everything 3m says for using 8115. Panel bond has its place, this wasn't it.

Agree. The best solution would to be to pop it loose with a propane torch and start over, but if I remember right Rod and I talked about that before when he posted pics of it in bare metal.

 

[Michael Brisebois]

Agree. The best solution would to be to pop it loose with a propane torch and start over, but if I remember right Rod and I talked about that before when he posted pics of it in bare metal.

I think you're in new territory. I never would have thought of that process, but that doesn't mean it won't work....doesn't look bad. Keep us posted on how it comes out

 

[67Dart440GT]

Most of the time what you will get is where your panel bond meets the filler you will eventually see a perfect line. This happens when you bake a car in a booth after priming or painting. It can also happen in the sun. I don't suggest panel bond on any seams that meet filler. Even though they say it's ok at a factory seem I have ALWAYS welded c pillars. The panel's should be flanged in my opinion. The way he put the panel on the style line created a lot of extra work for you.

 

[KosmicKuda]

The panel's should be flanged in my opinion. The way he put the panel on the style line created a lot of extra work for you.

I don't want to hijack this post but it contains good info that I can use (or unfortunately for the OP, not use) Does 3M have a "debonding" procedure? Surely they've tried it. I would think heat would cause warpage.
I have a 64 Valiant that needs the same panels so do you guys recommend a lap joint horizontally and NOT butt welded?
P.S. I love my MIG and have the panels.

 

[zkx14]

By welding the holes the panel is now welded on...

 

[GeorgeH]

I think you're in new territory. I never would have thought of that process, but that doesn't mean it won't work....doesn't look bad. Keep us posted on how it comes out

You can heat the seam up with a propane torch, get a putty knife in there, and usually get the panel off without destroying it if you go gently.

 

[GeorgeH]

Most of the time what you will get is where your panel bond meets the filler you will eventually see a perfect line. This happens when you bake a car in a booth after priming or painting. It can also happen in the sun. I don't suggest panel bond on any seams that meet filler. Even though they say it's ok at a factory seem I have ALWAYS welded c pillars. The panel's should be flanged in my opinion. The way he put the panel on the style line created a lot of extra work for you.

I have seen the seams "raise" as well when the car is parked in the sun. Over time it usually cracks, moisture get in, and then the panel is coming loose from corrosion in the seam.

 

[67Dart440GT]

I don't want to hijack this post but it contains good info that I can use (or unfortunately for the OP, not use) Does 3M have a "debonding" procedure? Surely they've tried it. I would think heat would cause warpage.
I have a 64 Valiant that needs the same panels so do you guys recommend a lap joint horizontally and NOT butt welded?
P.S. I love my MIG and have the panels.

I believe 3m suggests heating the panel to 400 degrees with no open flame and peel apart. I have always liked flanging a weld instead of butt welding. I used to work at a restoration shop and the owner insisted that we always butt weld. I never wanted to see how it would hold up in another collision. I have always used an air flange tool and then welding the inside so you cannot detect the seam.

 

[72bluNblu]

Flanges trap moisture, which creates rust. Look at the panels you're replacing. Where did the rust start? At a flange. Add more flanges, add more places to trap rust. And of course there's a seam. Put the seam on the outside and you have to fill it, put the seam on the inside and you can see the repair. Of the two of course its better to put the seam on the inside, if you have to hide your work under body filler you're doing it wrong.

Butt welding is the harder way to do it, it's easier to warp the panel with heat. It's the correct way to do it though. If it's done properly it should be just as strong as the original panel and there's no seam to detect. The weld has to be hot enough to be a proper weld (you shouldn't be worried about it's strength at all), but not so hot as to warp the crap out of the whole panel. There's a few methods, you can hammer weld as you go, or use a wet rag to cool and shrink the weld area immediately after the weld. The end result is a higher quality repair.

 

[GeorgeH]

Flanging makes for a stronger and easier to weld seam for sure, but it sure makes an ugly seam to dress up on the inside. It can't be done on every car, but on this one I would have trimmed the replacement panel on the bodyline and slid it inside. The inside seam would have been right at the bodyline so a finger wipe of plastic or a really tight wipe of seam sealer would make it nearly invisible.

 

[72bluNblu]

Of course flanging it is easier. So is slathering the quarter in fiberglass and bondo instead of doing all the metalwork to get it straight. That doesn't make it the right way to do it.

If you flange it because that's the easier way to do it, that's fine. Not everyone has the skill to do the repair with the proper method, and that's ok. Butt welding a panel like that is difficult, it's easy to warp the panel. Flanging it takes less skill and that will ultimately mean less bodywork for someone that doesn't have the skill to do the butt weld without warping the quarter. But if you flange it, don't go through the extra trouble of then covering it up so you can pass the car off as something it isn't. Just leave it the flange seam- that's the way you did it. It's not the best way, but it's ok. There's a seam there, and the next guy will know that's how the repair was done and can make a decision from there. There's nothing wrong with that, if you flanged it and did a good job the repair will still hold up for a long time.

I mean seriously, why hide the seam? It's on the backside of the quarter panel in the trunk. You don't see that at a car show. You don't see that at all unless you're looking for it. The only reason to go through any extra trouble to hide the seam is to hide the fact that the repair was done that way. Which means you already know it wasn't the correct way to do the repair, and you're trying to hide that fact from someone else. Maybe the next buyer? If you do the repair the way it's supposed to be done, there's nothing to hide. If you flange it that's fine, but don't hide it so you can pass the car off as a higher quality build than it really is.

Disagree if you want, but there's a reason why restoration shops insist on using butt weld on panel replacements like this. It's the best way to do it, and it's the right way to do it. It's also probably the hardest way to do it, but that's life.

 

[67Dart440GT]

Using a flange isn't due to lack of "skill" Most people don't have the skill to flange a panel the "correct" way. Also I guess every car that's ever had a proper sectioning procedure done on a rocker, or pillar was done incorrectly with a backing plate right? Also when butt welding the panels together you would still need to finish the weld on the inside of the trunk area right? Or those come out so perfectly you don't even notice it's had a panel replacement . The purpose of finishing a weld (butt or flange) on the inside is to restore the vehicle to pre repair condition... It didn't have a flange OR a butt weld from the factory. It isn't trying to HIDE anything. If that was the case why do mud work or repaint the car in the first place? You're just hiding a poor repair right?? And FYI most restoration shops I've worked for didn't want the butt weld done.. Just one.. and the reason he did is because it's "less" work to finish the inside. I'll keep doing it the way I have for the last 21 years.

 

[GeorgeH]

Of course flanging it is easier. So is slathering the quarter in fiberglass and bondo instead of doing all the metalwork to get it straight. That doesn't make it the right way to do it.

If you flange it because that's the easier way to do it, that's fine. Not everyone has the skill to do the repair with the proper method, and that's ok. Butt welding a panel like that is difficult, it's easy to warp the panel. Flanging it takes less skill and that will ultimately mean less bodywork for someone that doesn't have the skill to do the butt weld without warping the quarter. But if you flange it, don't go through the extra trouble of then covering it up so you can pass the car off as something it isn't. Just leave it the flange seam- that's the way you did it. It's not the best way, but it's ok. There's a seam there, and the next guy will know that's how the repair was done and can make a decision from there. There's nothing wrong with that, if you flanged it and did a good job the repair will still hold up for a long time.

I mean seriously, why hide the seam? It's on the backside of the quarter panel in the trunk. You don't see that at a car show. You don't see that at all unless you're looking for it. The only reason to go through any extra trouble to hide the seam is to hide the fact that the repair was done that way. Which means you already know it wasn't the correct way to do the repair, and you're trying to hide that fact from someone else. Maybe the next buyer? If you do the repair the way it's supposed to be done, there's nothing to hide. If you flange it that's fine, but don't hide it so you can pass the car off as a higher quality build than it really is.

Disagree if you want, but there's a reason why restoration shops insist on using butt weld on panel replacements like this. It's the best way to do it, and it's the right way to do it. It's also probably the hardest way to do it, but that's life.

Agree that butt welding is the best method but a pet peeve of mine is opening the trunk of a pretty car and seeing scabbed together stuff. Something needs to be done to the seam inside to at least keep moisture out anyway. So if you're going to do a lap joint and it can be done neater for a better appearance so be it. Even butt welds need some form of finishing on the inside for appearance.

 

[GeorgeH]

Using a flange isn't due to lack of "skill" Most people don't have the skill to flange a panel the "correct" way. Also I guess every car that's ever had a proper sectioning procedure done on a rocker, or pillar was done incorrectly with a backing plate right? Also when butt welding the panels together you would still need to finish the weld on the inside of the trunk area right? Or those come out so perfectly you don't even notice it's had a panel replacement . The purpose of finishing a weld (butt or flange) on the inside is to restore the vehicle to pre repair condition... It didn't have a flange OR a butt weld from the factory. It isn't trying to HIDE anything. If that was the case why do mud work or repaint the car in the first place? You're just hiding a poor repair right?? And FYI most restoration shops I've worked for didn't want the butt weld done.. Just one.. and the reason he did is because it's "less" work to finish the inside. I'll keep doing it the way I have for the last 21 years.

I don't live in a perfect world either. I've been doing it a long time and still can't pull off a butt weld flawlessly.

 

[72bluNblu]

Using a flange isn't due to lack of "skill" Most people don't have the skill to flange a panel the "correct" way. Also I guess every car that's ever had a proper sectioning procedure done on a rocker, or pillar was done incorrectly with a backing plate right? Also when butt welding the panels together you would still need to finish the weld on the inside of the trunk area right? Or those come out so perfectly you don't even notice it's had a panel replacement . The purpose of finishing a weld (butt or flange) on the inside is to restore the vehicle to pre repair condition... It didn't have a flange OR a butt weld from the factory. It isn't trying to HIDE anything. If that was the case why do mud work or repaint the car in the first place? You're just hiding a poor repair right?? And FYI most restoration shops I've worked for didn't want the butt weld done.. Just one.. and the reason he did is because it's "less" work to finish the inside. I'll keep doing it the way I have for the last 21 years.

It's absolutely lack of skill. A properly executed butt weld should just need to be knocked down with a sanding disk, front and back. Surface prep and hiding a flange weld with bondo are two different stories. After the butt weld has been done properly and prepped the metal will be the same thickness as original. There's literally nothing to see if the butt weld is done and then prepped correctly, the metal is the same thickness and functions as original. You're not hiding the work, you're doing the work. There's no overlap to trap rust, there's no seam, all that's left is metal that's the same thickness as it was originally. When you do a flange, even if you do everything correctly like it's supposed to be done, there is a seam and there is a flange where the metal is overlapped. Which is fine, that's a product of that kind of repair. If you then hide that seam because you know it's not supposed to be there you're just screwing someone over because you didn't do the work in the best way possible. Leave the seam, own up to your work.

Backing plates are a different story. If the weld is truly executed properly- ie, it's a full thickness weld with good penetration, you shouldn't need backing plates. That's absolutely true. Have I used them? Sure I have. It's extra insurance to have a gusset plate back there behind the repair especially if the weld on the surface is going to be sanded flush. Should the weld need a backing plate? No, it shouldn't. But on a rocker, or on a frame rail where you're doing a section, you can't see the back of the weld you're doing. The backing plate or gusset is an extra step to make sure the structure of the car is sound. That's different than repairing a body panel, even if you can argue that the quarters on these car do have a structural function. They do, but it's not the same as a rocker or frame rail. Yeah on a frame rail I'd rather have a gusset plate behind my work, but I'm also not going to go out of my way to hide it. It's back there, some of them you can see, some you can't. I haven't tried to hide any of them.

That's the problem with bodywork. For every one person that knows how to do it and insists it's done correctly there's a hundred bondo slingers just trying to make it shiny to sell at the highest price to some poor bastard that doesn't know what he's getting. We all ***** and complain when we buy a car and find out it's a bondo bucket with a bunch of short cut repairs, but no one seems to want to do the repairs correctly when it's actually them doing or paying for the work. Funny how that goes.

Agree that butt welding is the best method but a pet peeve of mine is opening the trunk of a pretty car and seeing scabbed together stuff. Something needs to be done to the seam inside to at least keep moisture out anyway. So if you're going to do a lap joint and it can be done neater for a better appearance so be it. Even butt welds need some form of finishing on the inside for appearance.

Well if a pretty car is scabbed together on the inside, it's not really a pretty car is it? Should it get the same price as a car that was done right and doesn't look all scabbed together? Or is actually scabbed together under a layer of bondo? That's the whole point of my argument here. You wouldn't pay for a car you knew was scabbed together, and you shouldn't pay more for a car that IS scabbed together because someone went out of their way to hide their work.

You can seal a flange weld without filling it with bondo. In fact, filling it with bondo doesn't seal it anyway, since most bondo is talc based and absorbs moisture, that's just a time bomb waiting to surprise someone else later. Seam sealer would be the way to do it, but then there's evidence of a repair because there's seam sealer where it's not supposed to be. Yeah, a butt weld can be prepped on the back side for appearance. But again, if the butt weld is done properly is just gets sanded down with a sanding disk so it's the same thickness as the original metal. That's not hiding the repair, that's finishing the repair. Properly finished the butt weld is just like the original metal, nothing to see. Properly finished a lap joint with a seam weld leaves a seam, and you should be able to see if no one intentionally tries to hide it.

 

[67Dart440GT]

Clearly you're the greatest body man that ever lived. I'm not even going to waste my time responding to that load of

 

[rod7515]

I appreciate all the information and knowledge that has been thrown out here. At this point Im not going to take apart whats already done so I guess I'll just try to make it straight and see what happens. Again Im no body man so Im not sure whats right and wrong. I do think the bonding material will hold together and I guess I'll find out what happens a few years down the road. One good thing is that the car will always be garaged and I will only be putting around 1500 miles or less a year on it. I'll keep you posted on the progress as I go forward and hope I can kick the body guy in the *** to get here.
Thanks again for all the information and thoughts.
Rod

 

[zkx14]

I'll keep you posted on the progress as I go forward and hope I can kick the body guy in the *** to get here.

Your time would be better spent just finishing it than trying to get him on it. You can do this!
Oh, and we will be looking for bi-monthly reports on the glue joint status ...with pictures of course.

 

[mycuda]

To be honest, what youve done will be fine. If that adhesive is everywhere you said, A few spot welds can only help.

But what do I know......

 

[GeorgeH]

One of the things most of us fussing could probably agree on is that if left unwelded the exposed edge seam that runs down the side of the car will crack the filler over it sooner rather than later. Some extra time now will save some headaches later. It might last a year or it might only last until the car gets flexed.