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Topic Review (Newest First)
03-07-2004 12:35 PM
Randy Ferguson adtkart,
Thank you for your compliments. We aren't going to agree on the repair procedures, so there's no reason to beat a dead horse, really. I have over 15 years experience in the collision repair business, so I know what ICAR and others recommend. However, that does not make them right. As I stated in my previous post IF a butt weld is done PROPERLY it is stronger than a lap weld. This is not a collision repair list, it's a hot rod list, we should strive to do quality work, not the crap I have to see everyday in the collision industry. Body shops do it fast for one reason...MONEY!
Real quality repairs take time, effort and skill. Bondo is not craftsmanship, it's a cheap alternative. I understand not everyone has time, nor the knowledge to metalfinish every car they do, but you must admit, it is best if you can. Please don't take this as a personal slam against you or anyone else on this list. I'm only trying to introduce another method that I believe is better than overlapping joints.
03-07-2004 09:25 AM
adtkart Randy.... I went to that site. Lots of great info there. The info that I posted about the "lap", oops "flange joints" being stronger, is based on ICAR information. This is reportedly, as I was not there, from testing done by them. I can say that my son has also done some non scheduled testing on their proceedures. The repair that you did on that fender looks great. I would have no problem with that type of repair, as it is not in an area that would have any real bearing on the safety of the vehicle. You can also get to the rear of the panel for refinishing and corrosion protection. In collision repair when welding panels, it is common to not be able to do that. A weld-thru primer is used prior to the pieces being welded together. The pieces are plug welded where they overlap and the edge can be welded up solid on the outside. Since mig welds are typically hardened welds, they are usually somewhat brittle, atleast more so than the original metal. Most of us have seen welds that appear stronger than they really are, specially when you only look at one side. For a professional, like yourself, to do work like that, is one thing. If it is going to be in a safety related area, I would personally trust the other method if I was going to becarrying my family in that car. I have inspected cars after accidents, with those types of repairs done. I have seen many of those welds fail.

I preferr to take the safe road, specially when it comes to something that I have no control of. Everyone can make their choice with the information in front of them. Knowing only one side, gives no choice.

I do recommend that site for anyone interested in metal working. LOTS OF INFO.
03-07-2004 02:12 AM
Randy Ferguson
Patch panel replacement.

Hi Guys,
I'm new to the list. My name is Randy Ferguson, not Rany, as I left out the n when registering! DUH!

This is an interesting thread for me, in that I'm a professional metalshaper and custom painter.

I just posted a photo essay on this subject at before finding this forum tonight.

There is a wealth of information in the forums there concerning all types of metalshaping.

Here is the URL for that post You may have to register first before being able to view it, but I think you will find it useful. I wrote the post in response to a guy wanting know how to weld thin sheetmetal without burn through. It's simple with a MIG welder if you take your time, and first practice on a piece of scrap sheetmetal the same thickness. I will agree with Kent White (Tinman) that other methods are better than MIG welding, especially for butt welding, by this guy wanted to know and I was out of argon for the TIG, so I used what I had. The end result is a stress free, butt welded panel that is just as strong at the original part, without worries of seeing a line or premature rust out and paint failure, common with lapped joints in sheetmetal. Properly done, a butt weld is the most sound weld possible, meaning that it is, in fact, just as strong as if it were a continuous sheet.

Here is a picture of the finished product.
03-05-2004 07:51 PM
adtkart OK Kevin.... you got me on the terminology. I guess I should have used the term "Flange Joint" instead of lap joint. I have just always referred to them as lap joints. I have always used that term when referring to an angled joint, like 2 pieces of square tubing at a 90 deg angle, where a piece of angle iron is used for a "flange" to weld to. Maybe that has caused some confusion. I am sorry about that.

The plug welds holding it in place, and the seams welded, give a really strong joint, along with helping to reduce the needed filler. They can be used, even with body lines, but take a little extra work that way.

Again.... I'm sorry for the confusion.
03-05-2004 06:52 PM
'35 Sedan Delivery This is a really good thread. [I don't know about the five stars, but it IS good.]

One way to see how much different the various techniques are, strength-wise as well as appearance-wise, would be to make up some pieces and test them. Surely, some authoritative source has done just this. Maybe ICAR, or some source like that.

[I'd love to do a search, but am going out of town for a week,starting tom'w morning.]

This way, we wouldn't have to depend on our own experience alone, or anecdotes, or references to manure (no criticism of the poster intended -- just the "expert", Tinman, he quoted).

My bet is that either the flanged overlap (plug- or spot-welded) or the butt weld is strong enough for body panels in daily driver use, provided that each technique is done properly, the frame is stiff enough to avoid excess flexing, etc.

Also you can't do a flanged overlap on 100% of each job, for instance, on patch panels where they go over deep body creases. So I'm learning to butt weld sheet metal properly, since I'm going to need that skill before long, regardless of what I might prefer.

Have a good week, all. Hope someone will do the search I described above.

03-05-2004 04:01 PM
patch panel fabrication

I-car teaches lap welding thats the oem reccomended way ifts it good enough for the oems its good enough for me ,they have to stand behind their warrantys they also reccomend using fusor weld bond adhesives where you use a caulking gun to apply 1/4 panels.
03-05-2004 03:49 PM
Kevin45 A lap joint is no stronger than a butt joint unless you weld both sides of the lap. If it would be then it stands to reason that a flange joint would be stronger yet. There are pros and cons to any type of joint. The thing is on a lap joint the metal doubles in thickness then with the filler over top of it more than likely make the total thickness triple or more. With a butt weld or a flange weld you can actually fill the gap and grind the weld down and maintain the original outside bosy line.

03-05-2004 09:54 AM
Originally posted by adtkart
. Just keep that in mind when you drive. They won't hold up as well as a lap joint, in an area that needs the strength in an impact.
A lap DOES seem stronger than a butt ever could be. But when roll cages are built, are not the welds BUTTS?
03-05-2004 06:57 AM
jimk I got the car when I was 14.Started driving it when I was 16.My bad.
03-04-2004 07:38 PM
adtkart jimk.... you can use whatever type of welds you want. Just keep that in mind when you drive. They won't hold up as well as a lap joint, in an area that needs the strength in an impact.

I didn't know that you can drive in Florida at 14 years old.
03-04-2004 10:09 AM
jimk I still stand 100% by what I said.Everything I did on my 54 chevy is butt-welded and it has been my daily driver for 15 years.But then again I have been doing it for a very long time.So if anyone got a little pissed,sorry,but it IS better(if you know how)to butt-weld.If you don't then use whatever works for you.
03-03-2004 05:33 PM
Killo.Richards I was just reading today...on Tinman's site that he calls MIG welding "Manure Shoveling" or something like that. Can't expect any mig welding to hold water...and when doing sheetmetal, you're doing mainly a series of tacks.

It doesn't take much skill to be able to tack sheetmetal with good penetration. But I do agree that it's way easier to screw up doing a butt weld than another type.
03-02-2004 11:02 PM
Hot Rod Hellion I agree with your post 35 sedan.

Everyone has their favored techniques, and my statement was out of line.

Humble apologies to all.
03-01-2004 10:49 PM
'35 Sedan Delivery Ron Covell is unquestionably one of the best metalsmiths ever. The metal forming video where he totally rehabs a 1932 Morgan three-wheeler shows his extraordinary skill. And, yes, he butt-welds all his sheetmetal. In fact he got that body so perfect, it didn't even need any filler!

But that Morgan's never going to be a daily driver (if it ever was), with its weird plunger suspension, ash frame, and wooden body sub-structure.

Ad kart's point about the metallurgy of welds governs here. A properly flanged lap joint that is either spot- or plug-welded is the only way to get a joint that is both strong enough for a daily driver and looks good.

My '35 Ford sedan delivery's roof on each side is flanged and spot-welded to the upper part of the roof above the windshield. This joint was finished with lead at the factory. After almost 70 years of hard use and enough rot of the lower body mounts to cause lots of flexing, those joints are undetectable.

It is neither true nor fair to assert that lap welds are for those who are "too lazy or unskilled to do it right." I don't care if you can butt-weld aluminum foil, HRH, that kind of comment is uncalled for.
03-01-2004 09:05 PM
Hot Rod Hellion If you're having problems getting penetration on sheet steel that is 18 gauge or less, you need to sell your welder.

If anything, the difficulty comes with having too much heat, and blowing through.

Butt welds, ground down to the original sheet thickness, are the right way. Period.

Lap joints are for those who are not skilled enough to get good edge gaps, or those who are too lazy to care. (production body shops)

Even the best in the business can get warpage when welding too.
How do you plan on using that hammer and dolly to finnish out a seam that is a double thickness?

For example, Ron Covell, Kent Smith, Ron Fournier are among a small handfull of metalshapers that are considered the best in the business, and highly respected in the street rodding industry. They all use butt welds for joining pannels.
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