RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-21-10 08:18 AM - Post#1918328
Hey all,
I finally had enough of watching this rust hole in my passenger side fender grow before my very eyes over the last few years. So I decided to take matters into my own hands. I thought I'd post some pics here for posterity and to seek guidance along the way. You know, since I've NEVER done anything like this before. Gulp.
This was a BIG, SCARY step for me.
Not real pretty under there (this brace looks gorgeous from the backside), but I'm hoping the POR will stop the decay.
P.O.R'd
Patch, made slightly smaller for butt welding. It came from the hood of a Corvair, how's that for recycling you greenies?!
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-21-10 08:24 AM - Post#1918330
In response to RaysnCayne
So I'm feelin' good about things up to this point.
But now I've got questions.
1. How should I dress the back of the patch panel? It's got the paint on it, but it's fairly flaky. Should I POR the entire backside of that too?
2. After I weld the patch in, how should I dress/seal it before putting the Bondo on? I feel like most guys immediately start slapping filler on at that point. But I've heard Bondo will actually draw moisture to the area and make it rust out again in 10 or so years. One friend told me to put POR on after the weld job then put the Bondo to it. Good idea? I've heard of epoxy (or etching?) primer, should I put a liberal amount of that on there first, then bondo, then primer, then paint?
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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wheelman
Valued Contributor
Posts: 2610
Loc: Long Island--New York
Reg: 04-14-07
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05-21-10 08:44 AM - Post#1918340
In response to RaysnCayne
I thiink Por15 is flamable so be cautious cause the heat from welding could cause a problem. I am not a body man but always have seen them clear all paint and coatings before welding. Looks good by the way, I also am tired of the rust but cannot even begin to afford body work..and am not capable of it on my own.
1968 Impala Sports Coupe
Old School
Save a Classic - Crush an Import
"King of the asphalt NOT Queen of the trailer."
My Impala |
Edited by wheelman on 05-21-10 08:45 AM. Reason for edit: No reason given.
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66cayne
Frequent Contributor
Posts: 1802
Reg: 08-06-08
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05-21-10 09:24 AM - Post#1918374
In response to RaysnCayne
Congrats, it looks good so far. What was the biggest hassle taking it off? The experts on this subject are in the 'paint and bodywork' section below. This is a common repair that they can help you with. You are very lucky the support
beam and the lower bolt attaching area is still intact. It greatly redused your fabrication requirements.
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-21-10 10:57 AM - Post#1918416
In response to 66cayne
The experts on this subject are in the 'paint and bodywork' section below.
Doh! All these years on this forum and I never even thunk to look for a section such as this! Doh!
The biggest hassle in my case was one or two bolts holding the fender to the core support. They were a pain to reach and so buried I couldn't get any WD-40 on them to loosen them up. Other than that, I was fortunate that all the other bolts weren't rusted and broke when I turned them. It was just getting up the nerve to remove a body panel and make a serious cut into my car. Ack! 
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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 59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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05-21-10 05:06 PM - Post#1918527
In response to RaysnCayne
Looking good, the proper way to prep the panel is with metal conditioner after the weld and grind, then epoxy it, and then use your bondo once it is dry, any metal that comes through should be re-epoxied, use a good 2 part epoxy, then your filler primer and paint, back side, wire brush as good as possible and use the POR 15 looking good !  my 2 cents, everybody has their way of doing it, but if you don't get the back side prepped right it won't last, paint is the easy part 
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YeniPenny
Dedicated Enthusiast
Posts: 5591
Loc: Biloxi, Ms
Reg: 11-26-01
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05-21-10 05:35 PM - Post#1918543
In response to 59fins
There is another school of thought on how to do this. Filler over epoxy primer isn't in the picture.
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-21-10 08:30 PM - Post#1918633
In response to YeniPenny
back side, wire brush as good as possible and use the POR 15
Okay Bill, your reply was one, big run-on sentence. I want to be sure I'm parsing it correctly when it comes to the back-of-the-patch-panel-p rep, just POR-15 it before I weld it in. And then do all that other stuff (to the outside) after it's welded in, right?
And Yeni, if I understand your vague reply, it's that I should just slap the filler right to the bare metal and go, y/n?
I went down to the Body and Paint section and it appears there's two distinct schools of thought on this subject. Lots of guys say put the filler straight on and go others are saying use epoxy primer to seal then do filler.
I would've thought the restoration industry would've figured this one out by now! But it seems they're still very much in the middle of this debate. 
Hey Steve (67SS427), you out there? What's your thoughts on this?
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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Black67
Forum Newbie
Posts: 47
Reg: 10-31-09
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05-22-10 02:38 AM - Post#1918710
In response to RaysnCayne
Sorry if this is a stupid question, but how come you didn't just replace the fender? Is it just a matter of getting a new one and screwing it back in or is it a unibody type of thing? Was it simply less expensive?
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59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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05-22-10 05:22 AM - Post#1918745
In response to RaysnCayne
back side, wire brush as good as possible and use the POR 15
Okay Bill, your reply was one, big run-on sentence. I want to be sure I'm parsing it correctly when it comes to the back-of-the-patch-panel-p rep, just POR-15 it before I weld it in. And then do all that other stuff (to the outside) after it's welded in, right?
And Yeni, if I understand your vague reply, it's that I should just slap the filler right to the bare metal and go, y/n?
I went down to the Body and Paint section and it appears there's two distinct schools of thought on this subject. Lots of guys say put the filler straight on and go others are saying use epoxy primer to seal then do filler.
I would've thought the restoration industry would've figured this one out by now! But it seems they're still very much in the middle of this debate.
Hey Steve (67SS427), you out there? What's your thoughts on this?
Body work is all about preparation, PPG suggest you put expoxy primer over bare metal then use fillers, that's exactly how I did my 59, like I said there are may ways to skin a cat, did I use metal prep everywhere? no, you must keep it wet for a period of time and large areas are hard to do that.
back side of patch panel, what ever you use is going to burn the back side, clean it as well as possible but not bare metal if possible, can spray the back side with weld through primer on the edges, if you leave the back side bare, you will be back in rust in no time cause the patch is being covered with the inner fender reinforcement, even if you stripped it to bare metal on the back side the edges are going to burn, and to get POR 15 or 3M rust fighter I in that area will be difficult.(but it is an spray can with a nozzle) the best is some original primer left on the panel (my opinion) just clean it up, put a coat of POR 15 on it staying about 3/8 inch away from the edge, and start welding, doing a little at a time in different areas to keep the heat down.
Bondo got it's bad name from poor preparation, most people put it on bare metal and that allows moisture to creep under it, specially in your climate and w/o garage, I've done body work for over 30 years and have tried all the different ways, as I mentioned above has worked the best for me, the epoxy seals the metal before bondo is applied, now bondo has come a long ways and is a good product, just don't by cheap stuff, you usually get what you pay for.
Don't expect the patch to be welded in and that's it, you will have to work the metal to be even with the old of even a tad below the old, is the paint original? feather it back till you hit original paint if not.
Bottom line is bodywork is not cheap, I used about 3000.00 in paint and supplies alone on my 59, but I stripped everything and used PPG system all the way through to the clear coat.
Zack, it looks like you are doing the best with what you have to work with, I am anal when it comes to bodywork, I would of sand blasted the inner reinforcement and the bottom of the fender and the edge of the fender, but that's me, just like anything, having the right tools for the job is a never ending thing.
my 2 cents again, sorry if I got windy
in metal prep
before epoxy
can see the primer filler on the fins on the right then ready for sealer and paint
Edited by 59fins on 05-22-10 05:27 AM. Reason for edit: No reason given.
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59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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05-22-10 05:42 AM - Post#1918756
In response to RaysnCayne
Zack I would grind the Corvair back about 1/4 to 3/8 inch on the edges so when you weld it's clean , looks like you spent some time on it, looks good for your first time out.
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 MPandC
"8th Year" Gold Supporting Member
Posts: 2993
Loc: Leonardtown, MD
Reg: 03-09-06
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05-22-10 07:05 AM - Post#1918785
In response to RaysnCayne
Looking at this picture, you already have noles forming in the fender brace. I normally use an ice pick to test the remaining area for structural soundness. Where it likely will last you quite a few more years, you are now at a point where it makes good sense to fix everything while you're there. Look through these threads, they may help with the process:
http://www.chevytalk.org/fusionbb/showtopic.php?tid/173828
http://www.chevytalk.org/fusionbb/showtopic.php?tid/205536
Next, to answer your questions, I'm in the camp that sees POR type paints as a last resort only, as they are not without issues of their own. I feel they should only be used in areas such as cowl or rocker cavities that you cannot gain access to properly prep otherwise for real paint. Anywhere in the vicinity of welding, and POR will put off some noxious fumes, so be sure to weld in a well ventilated area and/or grind the POR back from the weld joint. My take on the situation is that you have good access to both the fender brace and patch to sandblast the affected areas, giving a good surface prep for spraying with an epoxy primer.
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YeniPenny
Dedicated Enthusiast
Posts: 5591
Loc: Biloxi, Ms
Reg: 11-26-01
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05-22-10 08:17 AM - Post#1918805
In response to RaysnCayne
And Yeni, if I understand your vague reply, it's that I should just slap the filler right to the bare metal and go, y/n?
I went down to the Body and Paint section and it appears there's two distinct schools of thought on this subject. Lots of guys say put the filler straight on and go others are saying use epoxy primer to seal then do filler.
Yes, there are two schools of thought. DuPont's suggested repair method is to apply filler directly to bare metal and they specifically say to NOT apply filler over primer. Here is the word from the horse's mouth.
http://pc.dupont.com/dpc/en/US/html/visito r/common...
Most PPG users say that it is OK to apply filler over primer. I have done some searching on PPG's website and so far have been unable to substantiate that one way or the other.
It is true that filler will absorb moisture/water if there is a hole in the metal on the back side, but it would do that even if you sprayed the area with primer first. If there's a hole, water will enter.
I suppose you just have to spend your money and take your chances. I've been applying filler to bare metal for several decades and will continue to do so.
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YeniPenny
Dedicated Enthusiast
Posts: 5591
Loc: Biloxi, Ms
Reg: 11-26-01
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05-22-10 08:49 AM - Post#1918821
In response to YeniPenny
Try this link...
http://pc.dupont.com/dpc/en/US/html/visito r/common...
See the note at the bottom of page one and others further into the article.
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-22-10 10:16 AM - Post#1918851
In response to MPandC
Wow Robert, just amazing work! That inner fender brace is a thing of beauty. You need to have a cable TV show crew come out to your garage and start your own show.
Yes, there are definitely some deep noles and I see that this kind of decay doesn't fly in your resto work. I took a small screwdriver and pecked away at the brace, she's definitely thin in spots and I did find one tiny hole. (The POR filled it up though.)
I must confess, as much as I want to do it right, this was to be a "quickie" job (the kind artisans such as yourselves despise, I'm sure). So I'm going to employ the POR crutch and cross my fingers that it holds til I can collect the tools and resources to do it right.
There's a few other areas on the car that need serious attention. It's been my plan for the last 2.5 years (since moving into our current house) to build a decent garage, pull my Cayne in and start doing some serious body work. But with the economy hitting us like it has, the wifie's not gonna let me spend our emergency savings on building the garage. So this little job is basically a stop-gap measure til I can put the car up on jacks in a proper garage for a year or two (or probably more) and really sink my teeth into a full-on body restoration.
Duly noted on the patch panel prep before grinding Bill. Will do.
So guys, what sort of filler should I look at using on this job? I'm hoping it ends up being a couple light skim coats to make it paint-worthy. I have a NAPA nearby. Do they sell a decent filler?
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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05-23-10 06:28 AM - Post#1919232
In response to RaysnCayne
Well Zack it appears that Robert has put us all to shame.
I was looking at what you wanted to accomplish, first time out and your patch sizing is pretty impressive, but those that do it from time to time and on a budget good start, I have never used Napa brand, I would Google PPG or Dupont and go to the paint and body store, might find a few other goody's you might have to have. just like anything, there is a cheap bondo and expensive, if you fix it like Robert does you won't need much  but all kidding a side it will take some practice, a quart price difference to a gallon may not be much if your planning on doing more areas, get a cheese grater from the paint store to cut the hardening bondo and a flat sanding block, a little 80 grit paper and 180/120, I'm sure there will be different opinions on sand paper and fillers, Primers etc just don't skimp on products that stay on the car and use system, Dupont PPG, etc.them probably the top 2 biggy's, you can always go the cheaper route if you don't think the repair will last. materials are not cheap!
Robert is a true artist, but not all repairs can be finished like that with a budget, then finding someone that does that kind of work is the next issue but that's a different post.
Keep us posted on your project, again for your first time out... looks good, just needs a little more prep, the rear edge that faces the door edge could be hard to weld, I'm sure the corrosion behind there will make that metal thin. good luck
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-23-10 11:16 AM - Post#1919329
In response to 59fins
I'll confess Bill, I started with the welding yesterday and my enthusiasm for this project has all but disappeared. 
You guys make it look so easy. For every nice tack I placed, the next one I'd try just burnt right through. (And yes, the edge along the door side and even more so the bottom edge, are VERY bad.) I'm using a friend's nice, small Miller MIG welder but the friend wasn't around to coach me through it. I figured I'd set the Voltage and Wire Speed according to the parameters on the inside of the door and go. But the results are so bad there's no way I'll show a pic of that here. I got it maybe half done and decided to stop for the evening before I really got frustrated.
I'm going to give it another whirl today (still without the aid of that knowledgeable friend) and hope a fresh focus gets me through it.
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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MPandC
"8th Year" Gold Supporting Member
Posts: 2993
Loc: Leonardtown, MD
Reg: 03-09-06
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05-23-10 05:09 PM - Post#1919478
In response to RaysnCayne
Zack, I think some of the welding issues you are having may be due to the POR paint contaminating your weld, otherwise it may be some rust has caused the metal to be pitted and thin from the back side. If you could post some pictures of what you have there, we may be able to get a better read on what is occurring and offer suggestion to fix it. Blowing holes in the metal may be as simple a fix as increasing the wire feed speed slightly.
I must confess, as well as you had the patch fitted up, nice and tight, it looked as if you had done this before. And it is not my intention to put anyone to shame, but merely to show that what outwardly may appear as overwhelming due to all the bends in the inner brace, is actually quite manageable once you break it down into simpler parts that can be welded together.
If the rear edge continues to give you issue, I would suggest bending the flange onto a new patch while you still have a pattern to follow. You can clamp the patch material to a bench and bend over a piece of angle, use a vice, etc. Many common tools can be used to fabricate that part with the bend to help in eliminating 1/3 of your welding. But I would say to insure you can bend up the replacement before cutting out the remaining that you don't lose your pattern. Also, the rear edge is not likely a perfectly straight bend, there usually is a slight change in angle/direction where the top of the rocker is located, so you may have to reposition your part how it is clamped ever so slightly in making the bend accurately.
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DeathSStar
Forum Newbie
Posts: 62
Loc: Midwest
Reg: 02-14-10
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05-27-10 06:17 PM - Post#1921611
In response to RaysnCayne
So based on this photo, those po-po center caps are available? 
Good luck with your project. I'm comtemplating how much body work I want to do on my own with the 67.
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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05-27-10 07:53 PM - Post#1921679
In response to DeathSStar
Ouch! Where's the love man?
You wouldn't want mine anyway. To make your cop car tribute look right you need 67-specific dog dish caps if you're running steelies. Or police caps if you're running Rallys. (I do have a gennie set of them but they ain't for sale!)
Fender Mending Update:
After a horrible welding job this past weekend (actually had to patch the patch!), I hope to finally get back to the fender this weekend. Grind, be sure I got it all sealed up. And then start slingin' filler.
Maybe I'll have her back together and lookin' like a real car by next weekend. We'll see...
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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05-28-10 06:03 AM - Post#1921807
In response to RaysnCayne
Any pics Zack, I know you don't want to show us the patch on a patch but we may help with some do's and dont's . don't be a shamed, remember the first time to pulled an engine or changed your brakes? it probably wasn't pretty either, but I bet next time you will do things a little different, and the time after that ...... without equipment you will never achieve perfection, but you can make it last with some experience under your belt, plenty of people that would like to help you here.
my first rust hole job I was 15 (1975), didn't even know anyone who did body work, went to Farm and fleet that had bondo that didn't need hardener, I used a 2x4 as a block and dad had an electric grinder. ( at least I had a corn crib to work in)
beat the edges in and filled it with bondo, had to wait a real long time cause it was air dry bondo, electric ground it a, slung more bondo and used the 2x4 and 80 grit paper, then 180, then pray bomb primer, it was a 64 Impala SS Butternut yellow ( Dad Paid 50.00 bucks for it and it was complete, nice black interior, pretty straigh car but lots of rust ...), it really looked pretty good I thought after filling all those holes, then we had mini course week at High School, I had all the "Holes patched up" and a body guy came in to teach us what to do, since my car was in primer spots, he told us how to finish prepping the car and with 6-7 of us working that week we got it painted, It looked like a million bucks, we painted lacquer and it came out pretty good, but the lack of knowledge it did last about a year or so, which living in Iowa the winter salt ate it up, it was my everyday car, so I leaned that bondo in holes is not the way to fix rust sorry about the novel but your first time out isn't always a hole in one
what ever that game is
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RaysnCayne
Frequent Contributor
Posts: 1001
Age: 38
Loc: Richmond, VA
Reg: 07-29-03
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06-01-10 10:44 AM - Post#1923696
In response to 59fins
Hey Bill (and any others who might be interested),
I sort of got the welding done on my patch this weekend. (Yes, still not to the bondo stage yet.) But in doing so it appears I shrunk the metal where the right side of the patch meets the old fender material. Now there's a pretty big valley there. While it could be filled with Bondo and smoothed out, I'm thinking seriously about taking Robert up on a very generous offer he made me offline to teach me how to do this right. It's not certain yet, but I may be rolling up his way this weekend to have him show me the hands-on right way to do this job.
I'll keep y'all posted.
'68 Biscayne
406/TH350/3.42-12 bolt
13.17 at 104mph
The Cayne |
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1968 Caprice 396
Contributor
Posts: 269
Loc: Lombard IL
Reg: 05-05-09
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06-01-10 12:54 PM - Post#1923739
In response to RaysnCayne
I'm no pro at welding but it sounds like you might have too much heat for the gauge metal you're using. And trying to butt-seam two pieces takes skill even with experience. I know you're going to get some help, but you can also try backing the seam with some copper to keep from blowing holes in the panels. Eastwood sells all kinds of neat little gadgets for this stuff.
Once you get some experience, try welding upside down for your next challenge.  You're not a true welder until you've got scars.
1968 Caprice 396 Sport Sedan
1967 Camaro RS Supercharged 355
2008 Audi S5 |
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echale3
Contributor
Posts: 156
Loc: Roanoke, VA
Reg: 05-12-10
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06-02-10 06:58 AM - Post#1924135
In response to 1968 Caprice 396
I'm following this one pretty closely, because I have some welding to do on my car, and if I can learn from other's mistakes and "right moves", that's all to the good, IMO....
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c-towndave
Forum Newbie
Posts: 90
Loc: North Royalton, OH
Reg: 12-21-08
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06-02-10 02:54 PM - Post#1924316
In response to echale3
I've got two videos: One for how to MIG weld auto sheet metal and one for trunk floor replacement. I can send them to a couple of you and then you can share with whomever else you'd like. Maybe "Cayne" and "echale" could PM me your address and I'll send 'em out.
Dave
Edited by c-towndave on 06-02-10 02:55 PM. Reason for edit: No reason given.
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59fins
"12th Year" Gold Supporting Member
Posts: 1880
Age: 52
Loc: Surprise Az USA
Reg: 04-07-00
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06-03-10 07:26 AM - Post#1924622
In response to RaysnCayne
Hey Bill (and any others who might be interested),
I sort of got the welding done on my patch this weekend. (Yes, still not to the bondo stage yet.) But in doing so it appears I shrunk the metal where the right side of the patch meets the old fender material. Now there's a pretty big valley there. While it could be filled with Bondo and smoothed out, I'm thinking seriously about taking Robert up on a very generous offer he made me offline to teach me how to do this right. It's not certain yet, but I may be rolling up his way this weekend to have him show me the hands-on right way to do this job.
I'll keep y'all posted.
Could stretched or shrunk, hammer and dolly and see if you can work it out, if stretched you may nee to shrink it with a torch and water, sounds harder than it is, is the metal real tight or like a tin can, hit it one way and the metal flops the other, then it's stretched,
I'm thinking seriously about taking Robert up on a very generous offer he made me offline to teach me how to do this right.
wouldn't have to pass that offer up if it were offered to me more than once, Zack go get a lessen , listen and ask questions, you have other spots you will be doing, you may as well learn from the best, then no bad habits are learned, don't think that your product will look like his, just get your basics and learn, not to many times an offer comes along like this. Good luck, any pictures you want to share?
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wheelman
Valued Contributor
Posts: 2610
Loc: Long Island--New York
Reg: 04-14-07
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06-03-10 09:32 AM - Post#1924672
In response to 59fins
Well if you need I have lots of parts you can practice on, fenders, quarters come on down, I won't even charge ya.
1968 Impala Sports Coupe
Old School
Save a Classic - Crush an Import
"King of the asphalt NOT Queen of the trailer."
My Impala |
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MPandC
"8th Year" Gold Supporting Member
Posts: 2993
Loc: Leonardtown, MD
Reg: 03-09-06
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06-03-10 09:41 AM - Post#1924675
In response to 59fins
Zach should be bringing his fender over this Saturday so we can look at what he has, learn from it, and then look at the best way to fix it into a more permanent repair (whatever that may be) using minimal bondo. While my shop is not the largest in the world, this does present opportunity for at least a few observers/participants.... If anyone else in the area would care to attend this "fender patch seminar", please send me a PT and be sure to include a cell phone number, just in case any plans change....
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MPandC
"8th Year" Gold Supporting Member
Posts: 2993
Loc: Leonardtown, MD
Reg: 03-09-06
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06-06-10 08:50 AM - Post#1925898
In response to MPandC
Zach showed up in the Biscayne, which really helped out to have a good pattern in the adjacent panels to work against. He was originally going to just bring the fender, but I think after all is said and done we can see that would not have worked as well.
Here is what we had to work with.
Where he had done a nice job of trimming his replacement prior to welding (especially for a first timer):
..........I think a lot of the problems he experienced was due to not testing the welder set up on some scrap pieces first and additionally some weld contamination from residual rust scale.
In trimming out repair panels for fenders, I have always tried to install a new flanged rear edge in order to minimize the vertical welds. The more welds, the more shrinkage, the more possibility of the panel moving. Where we could planish out the welds in an attempt to counter some of this shrinking effect, that is not possible behind the fender brace, so what he ended up with was this:
......where you can see the replacement patch has pulled in a couple different areas to noticeably widen and distort the door to fender gap. I point these out not to pick on his work, but to highlight the possible effects of installing the patch in this manner that perhaps another method should be considered.
Where the vertical weld seam on the right side was clear of the brace to allow for planishing the welds, this had not been done and serves as a good demonstration as to how the metal will shrink. If we were to look at the profile of the lower fender from the side, it appears much as an arc (to simplify things). Due to the heat from welding and the subsequent shrinking we always hear of, the effect in the case of an arc will be for it to lose some of its radius to more closely resemble a straight line. In this case, what we see is a valley down through the middle of the weld as that exact result occurred.
Prior to removing the fender, it was marked with a reference line to be able to duplicate the rear edge location once a new patch was fitted into place. Where the fenders rear edge had distorted, the mark was adjusted to provide for a consistent door gap.
The fender was removed and Zach mastered fairly quickly the fine art of spot weld removal using a cutoff wheel. You can plainly see as the outer layer gets hot (speed is required here to generate heat), especially pronounced when the layer begins to thin, it will turn blue in color. When you begin to see the silver color of bare metal right next to the blue, you are now into the second layer. Time to stop there, grind a bit more around the perimeter of blue, and gently pry to check if the panel will release.
Where the lower flange of the fender had some rust issues of its own, we had to duplicate the contour around the lower mounting bolt.
The lower flange was bent and the new weld seam was moved slightly to the right to remove some of the valley more easily and to also provide more room for planishing both the weld and the HAZ (heat affected zone) adjacent to it.
The fender was refitted (one of many times) to insure the distortion had been removed and we had a nice straight panel in alignment to the door...
Then the patch was aligned to the lower flange mounting hole, trimmed to fit, clamped inplace, and marked for the fender rear edge flange.
To show what is possible using "basic" tools, and since the bend is not prefectly straight, a short section of wedge "anvil" was clamped in the vice and a low crown hammer used to gradually form the bend. A shrinker and stretcher also came into play to duplicate the "arc" profile of the fender, and this was checked to the front edge fo the door....
Then the patch was welded to the fender. I normally use weld "dots" in Mig welding sheet metal, and the machine gets set a little hotter (full penetration welds) and wire feed speed a little faster (less chance of blowout). Then the weld dots will be planished out, ground down just above flush (gets them out of the way for planishing the next set) and then planish the HAZ next to the welds as required. The top right cut was done using a large radius, which helps to reduce the shrinking effects that get comnpounded when working in a tight 90 degree corner. Where the inside radius will still shrink a bit more than the outside, the radius does make it a bit more manageable. Usually the HAZ on the inside radius is just planish a little more than the outside radius.
Where we did wind up with a slight depression right over the brace (should have put a bit more crown in the panel) Once Zach gets it all painted up it should last him quite a few years to come. I think he has a much better appreciation for working with sheet metal now, and look forward to his progress photos in the future..
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 70BelAirHT
"9th Year" Silver Supporting Member
Posts: 538
Loc: Qc, next to Maine's Borde...
Reg: 06-09-03
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06-06-10 09:52 AM - Post#1925926
In response to MPandC
Wow, that's a neat job, awesome!
Mathieu Bélanger
Québec, Canada
1970 Bel Air HT 2 doors 350, in restoration since 2002
1970 Caprice HT 2 doors 454
2008 Nissan Quest SE |
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drtyler (4)
