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About rust prevention and panel bonding method at the time of restoration, mainly at the time of welding.

RYO5566

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Hello!
Currently, we are replacing and repairing the body panel.
So the question is, how do you glue the body panels other than the frame?
I scraped the panel adhesive surface to roughen the skin, and I was thinking of bonding with 3M panel bond and spot welding.
However, in 100V spot welding, if the panel bond was sandwiched, it could not be bonded (is the voltage insufficient?)
Is it only necessary to use a panel bond for panels other than the frame where force is not applied?
Or is it better to do point welding instead of using panel bonds?
Also, it would be helpful if you could tell us about measures against rust caused by heat during point welding (heat-resistant rust preventive paint, etc.).
thank you for reading it until the very end!

20200617_154723.jpg
 

Adam

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I would treat the rust with a rust converter/neutralizer product; usually contains phosphoric acid. In the U.S. some product like “Ospho”. I don’t know if that’s available in Japan...

There are also “weld through” primers available at places like Eastwood.com Self-Etching Weld-Thru Primer Aerosol (Gray) – Eastwood
although you could just use etching primer instead of weld through.

After the rust has been neutralized you should spray the area with epoxy primer. Then you could scuff the epoxy primer with a green scotchbrite pad and use the panel adhesive between the primered and scuffed parts. Sometimes I use sheet metal screws to hold the panels together while the adhesive sets up, if a clamp is not possible in that area. Then weld up the holes later.

I don’t think you need both adhesive and spot welds, the adhesive is crazy strong... but I understand. When I replaced my roof panel I used adhesive along the rain gutters, and plug welds in the window channels. On these cars adhesive was not used originally, only spot welds. Since I do not have a spot welder that can reach areas like the center of the trunk pan I use plug welds.

In the areas where I want to simulate a spot weld (plug weld), I will drill or punch a hole in the top panel clamp or screw the panels together and use a scribe to scratch the primer off the base panel; then I used a Mig to weld the panels together, in the hole. To minimize warpage, burnt primer, or burnt panel adhesive, I have a wet rag and immediately quench the weld. I use the same technique to weld up the screw holes.

pics 28, 29, & 125 to 135, are examples. Challenger
 
Last edited:

NoCar340

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Wherever there was a spot weld, you can plug weld as Adam said. A pneumatic hole punch will save you a lot of time along edges. Anywhere there was a spot weld, use a plug weld if possible. Plug welds are much stronger than butt welds. It is important to remember these cars have unitized construction, so most body structure is stressed. Weld where you can. I use SEM Copperweld weld-through primer after trying most other types and brands. It is expensive. It is worth the cost.

I changed the roof on my Challenger, a front frame rail and floors in my Valiant along with subframe connectors, and converted both cars' floors to 4-speeds using a 110V MIG welder with carbon dioxide gas. It is perfectly suited to what you're doing.

Like Adam, I welded the new roof on my Challenger in the window channels and at the pillars, but I used 3M panel bond to attach it to the drip rails. Wherever you use panel bond, clamp those surfaces together firmly for the recommended cure time. Waiting longer would not harm anything. You do not need to use both panel bond and welding. The heat of welding will simply weaken the bonding agent.

After welding or bonding, all bare metal should be etch primed as soon as possible. DO NOT use any "magic paints" such as POR-15, Chassis Saver, Zero Rust or equivalent. No matter how good the prep, they will only cause problems later. There's a good reason no professional restoration shop uses that stuff, and it's not the price. Using good quality primers and paint will ensure a long and happy life for your sheetmetal.

Returning to the subject of the hole punch: I use an Astro Pneumatic 608ST which has a panel flanger in the other jaw. Once you have one you will not want to be without it. It requires at least 90PSI to work correctly... I learned that the hard way.😄
 

RYO5566

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I would treat the rust with a rust converter/neutralizer product; usually contains phosphoric acid. In the U.S. some product like “Ospho”. I don’t know if that’s available in Japan...

There are also “weld through” primers available at places like Eastwood.com Self-Etching Weld-Thru Primer Aerosol (Gray) – Eastwood
although you could just use etching primer instead of weld through.

After the rust has been neutralized you should spray the area with epoxy primer. Then you could scuff the epoxy primer with a green scotchbrite pad and use the panel adhesive between the primered and scuffed parts. Sometimes I use sheet metal screws to hold the panels together while the adhesive sets up, if a clamp is not possible in that area. Then weld up the holes later.

I don’t think you need both adhesive and spot welds, the adhesive is crazy strong... but I understand. When I replaced my roof panel I used adhesive along the rain gutters, and plug welds in the window channels. On these cars adhesive was not used originally, only spot welds. Since I do not have a spot welder that can reach areas like the center of the trunk pan I use plug welds.

In the areas where I want to simulate a spot weld (plug weld), I will drill or punch a hole in the top panel clamp or screw the panels together and use a scribe to scratch the primer off the base panel; then I used a Mig to weld the panels together, in the hole. To minimize warpage, burnt primer, or burnt panel adhesive, I have a wet rag and immediately quench the weld. I use the same technique to weld up the screw holes.

pics 28, 29, & 125 to 135, are examples. Challenger


Thank you for a polite answer!
I've never heard of a weld-through primer.
I'm interested in a heat-resistant primer, but unfortunately it doesn't seem to be on sale in Japan.
There is a primer for welding in Japan, but the heat resistant temperature seems to be limited to 1472 ° F.
I was thinking of plug welding as the place where stress is applied, but I will apply the primer to the part where the panel touches and cool it immediately as advised so that there is little damage!
Similarly, when using a panel bond, is there less damage if it is cooled immediately?
Also, what is the size and feel of the plug weld holes?
I showed you the pictures of the work! I am working very energetic and all of them are very helpful!
In Japan, there are no individuals working, and car dealers spend a huge amount of money and time working.
Thank you for the very polite explanation!
I look forward to working with you!
 

RYO5566

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Wherever there was a spot weld, you can plug weld as Adam said. A pneumatic hole punch will save you a lot of time along edges. Anywhere there was a spot weld, use a plug weld if possible. Plug welds are much stronger than butt welds. It is important to remember these cars have unitized construction, so most body structure is stressed. Weld where you can. I use SEM Copperweld weld-through primer after trying most other types and brands. It is expensive. It is worth the cost.

I changed the roof on my Challenger, a front frame rail and floors in my Valiant along with subframe connectors, and converted both cars' floors to 4-speeds using a 110V MIG welder with carbon dioxide gas. It is perfectly suited to what you're doing.

Like Adam, I welded the new roof on my Challenger in the window channels and at the pillars, but I used 3M panel bond to attach it to the drip rails. Wherever you use panel bond, clamp those surfaces together firmly for the recommended cure time. Waiting longer would not harm anything. You do not need to use both panel bond and welding. The heat of welding will simply weaken the bonding agent.

After welding or bonding, all bare metal should be etch primed as soon as possible. DO NOT use any "magic paints" such as POR-15, Chassis Saver, Zero Rust or equivalent. No matter how good the prep, they will only cause problems later. There's a good reason no professional restoration shop uses that stuff, and it's not the price. Using good quality primers and paint will ensure a long and happy life for your sheetmetal.

Returning to the subject of the hole punch: I use an Astro Pneumatic 608ST which has a panel flanger in the other jaw. Once you have one you will not want to be without it. It requires at least 90PSI to work correctly... I learned that the hard way.😄


Thank you for a polite answer!
As a result, the combination technique of panel bond and welding is not good.
It's best to separate the bond and weld parts!
SEM Copperweld is very worrisome, but unfortunately it doesn't seem to be on sale in Japan.
How far can you handle with heat-resistant primers made in Japan?
As NO CAR 340 says, when using a panel bond, I would like to work with a vise pliers etc. so that it adheres firmly!
POR15 has become a hot topic among Japanese restorers and is recognized as effective in repairing rusted iron plates, but is it rated low in the United States?
Hole punch tools are more efficient than drills!
I asked Mr. ADAM, but what is the diameter and spacing of the punch holes?
Thank you for your very polite advice!
 

NoCar340

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I bought several locking pliers (Vise Grip) that look like C-clamps. In fact, I have 16 standard ones and 4 long-reach sets. I used those to clamp the roof while bonding, but regular screw-type C-clamps will suffice.

The hole punch to which I posted the link makes 8mm holes, a similar size to the original spot welds.

If you cannot find weld-through primer in Japan, try searching for "cold galvanizing compound" in a spray can. It is essentially high-zinc spray paint. Weld-through primers do burn away right at the weld but stay in the adjacent areas. They're also electrically and thermally conducive. That is what is most important.

A lot of people in the US like and use POR-15. An equal number of people have had problems with it, including myself and a good friend. I was lucky since the car had not been assembled or painted. Rich was not so lucky. Three years after he finished the paint, the POR-15 had lifted and trapped moisture against the metal. He had large rust holes where there had been none. We both prepped the metal exactly as instructed on the can. The repairs his car needed were as extensive (and expensive) as the first time he did it. Virtually no high-level restoration shops here in the US use those types of paint. People on TV shows recommend it because they are paid to recommend it.

Good shops use quality automotive primer and paint. You should do the same. Applied properly, you will never have an issue.
 

Adam

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Thank you for a polite answer!
As a result, the combination technique of panel bond and welding is not good.
It's best to separate the bond and weld parts!
SEM Copperweld is very worrisome, but unfortunately it doesn't seem to be on sale in Japan.
How far can you handle with heat-resistant primers made in Japan?
As NO CAR 340 says, when using a panel bond, I would like to work with a vise pliers etc. so that it adheres firmly!
POR15 has become a hot topic among Japanese restorers and is recognized as effective in repairing rusted iron plates, but is it rated low in the United States?
Hole punch tools are more efficient than drills!
I asked Mr. ADAM, but what is the diameter and spacing of the punch holes?
Thank you for your very polite advice!
The holes should be spaced to approximate spot welds, so every couple of inches... also the holes should be about the same size. My hole punch gun is 8mm, which works well. If the holes are too small the mig wire will likely arc to the side of the hole instead of the bottom; if the holes are too big too much heat/wire will be required to fill the hole. Also, you can grind down the plug welds with a flap disc, but be mindful that this produces a lot of heat and can cause warping... so a little at a time is better than grinding all at once.
 

RYO5566

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I bought several locking pliers (Vise Grip) that look like C-clamps. In fact, I have 16 standard ones and 4 long-reach sets. I used those to clamp the roof while bonding, but regular screw-type C-clamps will suffice.

The hole punch to which I posted the link makes 8mm holes, a similar size to the original spot welds.

If you cannot find weld-through primer in Japan, try searching for "cold galvanizing compound" in a spray can. It is essentially high-zinc spray paint. Weld-through primers do burn away right at the weld but stay in the adjacent areas. They're also electrically and thermally conducive. That is what is most important.

A lot of people in the US like and use POR-15. An equal number of people have had problems with it, including myself and a good friend. I was lucky since the car had not been assembled or painted. Rich was not so lucky. Three years after he finished the paint, the POR-15 had lifted and trapped moisture against the metal. He had large rust holes where there had been none. We both prepped the metal exactly as instructed on the can. The repairs his car needed were as extensive (and expensive) as the first time he did it. Virtually no high-level restoration shops here in the US use those types of paint. People on TV shows recommend it because they are paid to recommend it.

Good shops use quality automotive primer and paint. You should do the same. Applied properly, you will never have an issue.
I bought several locking pliers (Vise Grip) that look like C-clamps. In fact, I have 16 standard ones and 4 long-reach sets. I used those to clamp the roof while bonding, but regular screw-type C-clamps will suffice.

The hole punch to which I posted the link makes 8mm holes, a similar size to the original spot welds.

If you cannot find weld-through primer in Japan, try searching for "cold galvanizing compound" in a spray can. It is essentially high-zinc spray paint. Weld-through primers do burn away right at the weld but stay in the adjacent areas. They're also electrically and thermally conducive. That is what is most important.

A lot of people in the US like and use POR-15. An equal number of people have had problems with it, including myself and a good friend. I was lucky since the car had not been assembled or painted. Rich was not so lucky. Three years after he finished the paint, the POR-15 had lifted and trapped moisture against the metal. He had large rust holes where there had been none. We both prepped the metal exactly as instructed on the can. The repairs his car needed were as extensive (and expensive) as the first time he did it. Virtually no high-level restoration shops here in the US use those types of paint. People on TV shows recommend it because they are paid to recommend it.

Good shops use quality automotive primer and paint. You should do the same. Applied properly, you will never have an issue.


Hello!
I also have some vise pliers, but I'm likely to need a long arm vise like Mr. 340, so I'd like to get one!
The hole for plug welding is 8mm in diameter. I was surprised that it was bigger than I expected.
If you search for cold galvanizing compound, you can buy it in Japan as well.
The biggest issue was how to prevent rust on the mating surfaces of the iron plates during welding, so thank you for letting us know!
It seems that POR15 is highly evaluated in Japan, but for me it is an imported product, so it is expensive, it can not be stored because it is a one-component solvent that does not use a curing agent, it does not adhere to the iron plate of rust-free skin, etc. There was a problem.
I will try using a high-performance primer as advised!
There is also a restore forum in Japan, but it was very helpful because it didn't give me such detailed advice!
I look forward to working with you!
Thank you!
The holes should be spaced to approximate spot welds, so every couple of inches... also the holes should be about the same size. My hole punch gun is 8mm, which works well. If the holes are too small the mig wire will likely arc to the side of the hole instead of the bottom; if the holes are too big too much heat/wire will be required to fill the hole. Also, you can grind down the plug welds with a flap disc, but be mindful that this produces a lot of heat and can cause warping... so a little at a time is better than grinding all at once.

Hello!
Thank you for your polite answer!
After all, like Mr. 340, the hole has a diameter of 8 mm.
Shaving after welding is done little by little while cooling so that heat does not accumulate.
It will take a long time to complete, but it is very motivating and encouraging to receive this kind of advice!
I look forward to working with you!
 
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