YES! I'm a hack too! I've lap welded in more patch panels then probably most of you guys have ever seen. I did it for more then 25 years. My work is in the rust belt on vehicles that are used as year around vehicles. You know, vehicles that sit out in the sun, get driven on rough roads, and get driven when the weather isn't so nice. During those years, I've replaced floor pans that I have already replaced before. In every example, after living more then 5 years on snow removal equipment, the original metal was rusted beyond last patch. In none of those cases, was the lapped joint area deteriorated, in fact the lap joint area was stronger then the metal on both sides of it. There is a correct way to lap weld a joint, but the earlier video isn't the way. I step flange the joint area, and weld the patch onto the flange 1/8" below the step, with the weld at the highest point of the metal joint. Then the weld fills the step. There is a lot less weld grinding involved. I've seen many butt welds that have more metal build up then most of the lap welds do. Most beginner butt welds are lumpy ugly welds of questionable quality. I don't see much possibility of the original poster to be able to get at the back side of his roof patch. I doubt he intends to cut the inner structure out of the roof to hammer and dolly the patch flat, then attempt to weld the inner structure back in. In a very high percentage of patch welds, access to the back side is a myth. Usually there is structure there that does not allow access, and usually that structure is not removed. When rear access is not available, a flanged lap weld gives the guy a much better chance of not having a warped pile after the welding is done. The welds are usually better quality because its easier to get good penetration and have better control of burn through. I guess if your building cars to compete at the Amber awards, the butt weld is the best choice, but if your building a hot rod to drive, butt welds pretty much suck until you get a lot of experience. Gene
A weld only has to be as strong as the parent metal. A properly fit butt weld requires a small weld. Small weld = less heat. Less heat = less distortion. Access to the back is not always necessary.
this piece wasn’t 100% assessable from the back side. The weld area was file fit. No gap. That’s easier to do than you think. The advantage is the minimal weld it took. The weld was barely 1/8 of an inch wide. Butt welding for the jamb area saves the filler transition. Meaning less filler work. If you start learning these skills now, it pays off later.
There have been a lot of good points made in this thread, and it all proves what we already know... that there is more than one way to skin a cat. The work that one person does or pays for... may not be acceptable for another. If I were doing or paying to have this job done... it would have butt joints and TIG welds. I would open up the gutter and repair what was needed, then spot or plug weld the gutter back the way it was meant to be. Some of these cars have outlived a few generations already... and I like to think they will be here for a few more. I always dread finding old repairs with license plate filler panels, cutting torch slag, coat hanger welds, and chicken wire filled bondo. My goal is to make the next owner proud to find my “old” repair... if he can find it
I just went through this with some lap welded - bondo shaped fenders on my truck! It was California built and owned. Let me start by saying this isn't my profession... Just a hobby/obsession I cut out the bad metal to the point I had good, clean metal, then clearly marked where the final cut would be for the patch panel. I have access to the back because the fender brace was rusted completely through, so it got removed and a patch created for it, once I finish the body work on the fender, it will be sealed up with nice 2K anti corrosive primer/sealer. Should last the rest of my life in the desert.
Interesting comments .....thanks As the guy actually posted a video on the lap "lasting" approach Like I mentioned ...... planning on using butt weld on 80%+ of the fixes ..... just not sure on the other 20% if I can get it that good in fitup - i.e the roof corner
If it wasnt accessible from the backside - how did you protect from rust ... meanign did you paint the rear of the patch before welding - and how can you be sure it didnt "burn" off on the weld seem.
Pretty much the area I was most concerned with and thinking I dont see how I get away without a lap joint here. thx
I sort of tried this on some scrap ...... theory makes a lot of sense ....... but tend to find its hard enough to cut through single sheet metal over large distances .... 2x thick ..... thats gonna burn through some wheels ... or maybe I need better wheels. Was thinking about using sheers ....... on a trace line ........ just not sure how accurate you can keep on the line .... https://www.harborfreight.com/14-gauge-5-amp-metal-shears-64609.html
Lots of ways to protect metal. A scuff pad on a paint stick can reach a lot of places. Paint gun on pin point, skinny paint brush, aerosol cans, adding a straw tip to a spray can, and wand attachments can coat just about anything. I will sand my panels before welding. Sometimes I epoxy them before welding but leave the weld area clean.
I use a very thin cutoff wheel in an angle grinder. It's not a fast process but the fitment leaves a wonderful gap.
Back when I was in my early 20's, I done patch panels in my 70 chevy truck, lapped them, welded with the old black coat hangers and a torch I borrowed from work!
I build competition cars, race cars, and street cars sheet metal never gets lapped unless it is a factory lap joint like a pinch weld on a resto. Many reasons lap joints will fail. Moisture, you can’t hammer the weld back out, and there will always be a ghost line in the paint from the lap seam. I know to mentioned no being able to get the back side to hammer out welds. The correct way would be remove the panel and hammer it out, Metal finish then replace at spot weld seam. I do it that way all the time. there are lots of people who do things lots of ways. But a flanged lap joint is just wrong. You kind of said so yourself by talking about if it was a show car it should be butt welded. So qaulity work should only be done on show cars? No, if it’s worth doing it’s worth doing right period.
I used to live in the roll back capitol of the world and that was a common used car lot trick. I actually knew a used car dealer with an old Wagoneer that he used for hunting that was done that way on all 4 doors, the tail gate and the rocker panels. he drove it that way for at least 5 years that I knew of. Best bet is to cut it back to solid metal and weld the patch on the front side then grind it. I have seen them with the patch lap welded behind the old metal and filled too. That would be less of restorers way of doing it and more of a pro body man way of doing it.
The show car reference was for an Amber show car. Most of the guys that come here are not going to enter their car in the Amber style show., or any show where a lap joint will cost him points over a butt weld at some judged show. They are also not going to remove a panel, repair it and replace it at the spot welds of a factory joint, which ironically is a flanged lap joint. Most are after something that looks good, lasts a long time, and is something they can safely drive and enjoy. I find it interesting that you mentioned a factory lap joint, but condemn my lap weld joints. I have to wonder, do you butt weld the roof panels to the sail panels, or do you do like the auto factories do and flange spot weld those too? Of course you understand that the factories used the lap joint welds in areas where they wanted and needed the extra strength of two layers of metal at those joints. And how is it that the auto factories have been using lap joints at the roof and sail panel for years without a ghost line showing up in the paint? I'm happy you feel so special because you build competition cars, race cars, and street cars and you only do butt welds (except of course for the lap welds that you do, you know, like the factories do for extra strength). Good for you. My track record with vehicles that actually get used in real life proves the worthiness of the welding I have done. I'd be pretty surprised if most of the stuff you build would never see what the stuff I've done sees on a daily basses. Some of the stuff I've flanged and lap welded have been in pretty bad crashes and have not failed. A good weld is a good weld. Most beginners fail to make good welds with butt welds. The thread was from a guy asking how to weld a patch panel in on his car. Butt welding was suggested as the only possibility to do it "right." I've offered another option that will get the job done, will be safe, and will last a long time. He does not have access to the back side. I doubt he is too concerned about a ghost line in the paint, and I suspect his welding abilities are probably not at an expert level like yours. The flanged lap joint it a good option for him and many like him just getting started. Gene
qtrs removed from a 59 impala. The entire bottom was replaced as were most of it where the upper fin welds to the qtr. Spot welds are easy to remove. The removal enabled all this work to be metal finished. Also the wheelhouses were repaired easily. these are the tops of the fins after being rebuilt and epoxied, did the same for the qtrs. The inner structure was also epoxied. Is this normal? In my world it was. We all come from different backgrounds. You have asked for advice and great suggestions have been given except maybe for that one video. My experience from the collision side removing welded parts is natural. For someone learning it may seem daunting. I really do not care which method you choose, it’s your ride. I’m glad to see ya attempt to save it. I’m actually surprised the panel bond junk hasn’t been brought up. As far as butt Vs lap. I was taught to flange or build sleeves when sectioning. This method was taught through I-car in their early days. Then I started working in a shop with access to factory repair procedures. None listed a flange or sleeve. Lead joints. Manufacturing techniques required many to use those large leaded seams. That’s no longer the case. I have removed many of them successfully. Or make joints in new parts that look better than the factory in these old beaters. this rocker, cowl and qtr pieces were built to eliminate the need for lead or other heavy fillers. I’d visit my friends in shops working entire sail panels (C pillars) with mud covering up lap or sleeved joints. We butt welding them and most times only needed a thin layer of a 2 part glaze. Some got nothing but primer. Your difficult spot is the roof. The drip rail area can be tricky. I’d probably save those spots for last after you get practice in the other areas. Good luck and get busy welding
thanks for the novel. I hope it made you feel better. You keep doing things your way. Doesn’t effect my Life in slightest
So .... started cutting .... Practiced on some 22 gauge as where I live the neareset "metal" supplier seems to be 60 mins away .... and for some reason the big box stores only sell 16 gauge or 22 gauge ...... and figured better to try on that to get dialled in. Got that done yesterday (messy looking welds but fully covered and not too many blow throughs ) --- so idea is to try and source some 20 gauge at the metal store whenever I can get there. SO q --- going to use the cut through method that your guys showed in fitzees videos ...... and think should be mostly good - still not sure on those tight roof corners but I'll deal with it one way one another ...... but here are some more pics with some metal cut out for access (and some practice welds to my 22 guage). 1) How do you deal with the corners (bends basically) to make sure it looks as close to original form as possible. 2) How do you guys think is best to deal with rust on bottom channel. I dont think I am going to cut it out as not sure I need to and what other issues it might create for my new body panel fabrication life ........ but do want to try and seal the rust after while weeling. Was thinking either vinegar solution .... or corrseal. Anyone have a vote or other thought ? thanks !
So tackling it this weekend ...... Started cutting more back ..... was planning on just dropping a straight sheet on the main cutout ... but I had to go more into the wheel well lip to cut out a previous patch repair ...... and further around the bumper ..... How would you guys tackle this from a perspective of .... 1) Think my cleanest long term options is cutting it all out not just a patch ........ but how many pieces should I try and do it in to get it back in and lined up ok ....... there are a few angles here I was thinkig .,,,,, a) tack some metal above where I can form the metal lip under the rear panel on the main strait section. b) create a small bended patch to blend into and attach for wheel fender. c) deal with rounder bumper area as a 3rd section. d) finish off with reverse (inside).
Sort of like this Weld the wheel piece after forming to the main pice then weld all in .... then deal with the light blue piece as a 3rd piece ..... just not sure about keepiong the line as the wheel well sort of cuts out whilst the metal at base cuts back in towards truck
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