Martinsr, Or any of you professional body men.Please tell your thoughts again on step flanging the body before applying the new quarter panal vs. butt welding. I was told it is not recommended to glue the panals on due to the chevelle has a problem with body flex under engine torque.

IMO the best way to do a partial panel or patch is to butt weld. Benifits to butt welding being that it will be easier to finish off and easier to treat the backside for corrosion protection. A stepped flange can be done or a butt seam with a backing strip but both methods will leave a joint that will be tough to treat for corrosion protection. And the flanging tool can cause a great deal of distortion-it tends to straighten out curves. I think the panel adhesive would work fine, I've used it on numerous bigblock cars and some were unibody design without any problems--contact Fusor or 3M or any adhesive company that you choose and question them if the product will work- I bet all will warrantee no problem. JMO here, some will argue that flanging is the best way to go because it adds strength which is true. Maybe you should start a poll? To flange or not to flange :D

I've heard that the modern metal adhesives are all but as strong as a weld, but I have also heard that eventually a seam line becomes visable. Any truth to this?

As far as corrosion goes, when using the panel adhesive (correctly), the seam should be perfectly sealed, not?

Just wondering.

I am no professional so mabe I can learn something here also?
I dont understand why you would be conserned about a flanged joint?
Aren't almost all the welded joints in an "A" body lap/flange joints?
I agree they are not in the middle of a pannel, but they are all over inside.
So if your welding is good and your filling, moisture proofing is good, whats the differnce between a new flange/lap joint and a 32 year old one?
I just dont understand? please explain why one will rust out and the other wont?
Also doesnt the flanging tool take such a small bite that it wouldnt affect curve of a large panel?
Seems one would go for the extra streinght of the flanged joint, to be sure it wouldnt crack or get the lines ?
Again Im just asking, cause I dont know?
T.C.

You took the words right out of my mouth T.C.

There isn't a single butt weld on any car made in the world in the past number of decades (save for a few handbuilt specialty cars).

I agree, the butt weld is the "best" way to make a repair in many cases. It is NOT the best way in others, there are a few places where it is simply impractical.

If you have the skills for butt welding, by all means use them. If you feel you are close to the skills, practice. They are very satisfying and the finished product looks so much better.

That being said, only YOU can say if it is the time for you to make butt weld as far as your skills. I much rather see you put a lap weld down the side of a quarter panel, finish the car and be out there with a smiling face behind the wheel than to be agonizing over a failed butt weld attempt.

I don't think the is one BEST way..Butt welds can be made invisible from both viewed sides.. Flanging is not a DIRYT word. and Glueing is State of the art .. each as it's strengths and weakness. I use all three methods.

As for distorting with a flang tool. Yes it can but some well placed wizzer slits in the flange
crimp. surface minamize it.. both concave, convex and radius.

Glue.. being old school..I was draged into the 20th centery.. I became a beliver.
I made 1/4's for my 65 elcy the Driver side has 7 panels with the gas door.. Read 30 + feet of weld seam.. So I flanged Some areas. Glued some areas and Welded Some areas..
Been 5 year now ?? and YES in the morning dew settles on it. You can see the seams.. but not the butt weld seams just as you can see the support structure of the under hood ect.

Well if thats the only time and way you can see the seams, then so what. I was thinking that they ment the seams would cause a line in the finish over time.

Good post.

Using a backing strip on the back side of a butt weld would work as long as you paint the strip with something like 3M's Weld-thru primer. Coat the back of the weld joint as much as possible also. If you can get to the back side at all, coat it with Por. I did this with my floor pans last year. I sprayed the 3M stuff on the bottom of the weld seam and on floor support beam I was welding to. (I used one leg of the floor support beam as a backing strip.) I also pryed the floor sheetmetal up and used a brush to apply the 3M primer where I couldn't get at it to spray it. Bottom line, with enough ingenuity, you can get something on the backside of a weld for corrosion protection.

Correct me if I am wrong, but don't all of those GM flanges and lap joints have a corrosion sealer between them before they are spot welded together? It has been my understanding that one of the drawbacks of "dip-stripping" a car body is that all of that corrosion protection that the factory put on the panels and in the welded seams is removed. Now you can replace the seam sealer on the outside, but not between the joints. At least that is what I have heard...although truthfully, I can't see putting sealer between all the welded joints before spot welding (very labor intensive and time consuming).
Nothing wrong with a flange/lap weld, just make sure it is sealed.

The older cars were welded together with nothing just bare steel before application of primers and sealers so these factory joints on these cars are infact bare inside unless primer or sealer has made it's way into the seam. A lot of the newer cars today have a seamsealer between the panels that is welded through and some use an adhesive and welding but the old cars were assembled as bare steel and then primed and sealed. Some seam sealers were applied over bare metal before the primer and after years they break down, crack and shrink exposing the bare metal underneath to start the rusting process. Bare metal should always be primed before an application of seamsealer IMO, I haven't seen a seamsealer designed yet that suggests it should be used on bare metal.

Thank you gentlemen for your input on this subject. It is really appriciated.

BadBob...so where is the break-over point for Chevrolet? What constitutes an older car that is welded without a seam sealer between? Do our Chevelles have it or did it come about later?

The break year who knows. It really hasnt been around for 10 years tops if that!!

Some new cars have a sealed seem some dont.
Plus you only see it on an exposed joint weather seem, not EVERY seem has it. Like a wheel well to 1/4 lip seem, the door skin, stuff that gets some weather thrown at it...Eric

BadBob...so where is the break-over point for Chevrolet? What constitutes an older car that is welded without a seam sealer between? Do our Chevelles have it or did it come about later? I'm not positive, but I think the first cars to use a weld through type sealer were in the late 80's But like Eric said not all new cars are using a weld through sealer or adhesive in critical areas, here is a fine example of failure on an 03 Taurus-

http://community.webshots.com/photo/244855436/244855901Fsnecv


The car only has 16000 miles on it and actually less than two years old. Just think it's galvanized and was ecoated after the welding process and still rusted bcause moisture was trapped in the seam. The factory uses no seamsealer on this area and dust and dirt accumulates then holds moisture. The doorskins are also starting to blister on this car where the factory skipped a spot here and there when applying the adhesive. Seeing stuff like this makes me sick and also makes me pay a lot more attention to how I do my work, I don't like failures.

So...would you say there are any drawbacks to stripping and e-coat dipping a 60's vehicle? I was going to have my '68 truck cab done by Ecoat King, but that may not be an issue anymore because I have heard they may have gone out of business.