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Learning to fab

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Learning to fab

idrivejunk idrivejunk
Addict | Posts: 4987 | Joined: 12/09
Posted: 11/25/13
09:33 PM

Well guys my last picture post on rust fixing is a year old or so now. Today I'm working on something that applies to 68-72 A-bodies. This is a '68 el Camino with a rusted out windshield bed. Must have been a real gusher once the second layer rotted thru and was dumping everything in the floor. I planned to put in a couple small easy-make patches but once I started cutting it became obvious that the task was growing.

In this case, I siezed the opportunity for some personal growth. Stepped up and used some of the simpler metal fabrication tools that surround me at work to my advantage. It was very rewarding for me to make my first four foot piece so I thought I would share it because I was alarmed at how easy it was, plus its relevant to GTOs and Tempests. I am definitely feeling more confident about fixing things where no replacement metal is available, and am thankful that I was given this opportunity to grow my ability. Here, I'll show you:

I was thinking I would patch just where the spray paint is, two layers each-

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That shiny spot at the far end is where I was gonna start, but the rust just kept on going so here is where I ended up after trimming the badly pitted and gone areas of the upper layer, the dash-

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same spot with flash, YUCK!

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Now the bottom layer (firewall) is trimmed out and everything is cleaned up with a purple stripping wheel.

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Got all that cleaned out. Picked up a partial sheet (most of a 4x8') of 18 gauge steel and went to our "stomp shear" with it. Thats a four foot wide chopper offer for metal, air powered with a foot pedal. KBAM! Had me a 1-3/4" wide strip four feet long. Now I went to the "metal brake", a four foot wide sheetmetal bender. Thats this thing, its hand-operated. See my strip laying crooked in the tool? Man, watch your fingers.

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Chopped a little sample piece off my old metal and duplicated that angle with the bender on my new strip-

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Then I took the bent strip to another tool, the "shrinker / stretcher". Its also hand operated, see lever. One set of jaws crimps, the other pulls apart. On up to like a 1" deep flange, see slot on side of tool. Thats where the magic hit me. Wow, that thing is cool. Opens up the door to me knowing how to make lots more parts than I did. I would have pie-cut the strip prior to this, and welded after bending to fit. Thats sloppier but can be an acceptable repair. This was fast!

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Once I had that curve down, I screwed it in place and trimmed the edges. Wicked! Thats the dash repair panel laying on top now, my new piece is screwed on.

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So after that, there was some self etch primer, some rust encapsulator, and ha, Chevy engine orange. This whole thing will be sandblasted but they can't reach in there so this is all it will ever get. I put plenty-

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Prepped for welding here. I did the plug welds first then tapped the front edge down to fit so the gap was better than this might show, when I actually welded that seam.

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This is how it looks at the moment. I have grinding to do. If you'll notice, I'm not really a welder just a bodyman who joins metal with a MIG. Good penetration and lots of smoothing afterward are the idea here. On outer skins I weld one spot at a time but I went up to 3/4" beads on this area.

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Questions, comments, polite observations are welcome. I'll finish this area tomorrow and show the top layer too. Thats actually the dash itself and we have that repair panel thats just the front edge. So that will be an even longer weld and warpage avoidance will be number one in that area. Its all just standard patch work but I wanted to show that long curved piece I made. I'm looking at rusty junk in a different light now!

By the way- I finished the quarters on this already and that was some challenging fabrication work as well. If you want to see more, speak up. There was rust behind both quarters and its pretty similar to regular coupe panels back there behind the rear wheels.  

4zpeed 4zpeed
Enthusiast | Posts: 351 | Joined: 04/13
Posted: 11/26/13
12:21 AM

I just happened to wake up, the laptop was on so I hit the refresh button, wow, look at you dude, lol. Nice post, most people don't realize how much work goes into a repair of that nature. Have to look again in the morning, I can barely see right now, just wanted to express some appreciation, good night, er a, morning.

Nice work man!

Poncho huggen gear snatchen posi piro.

wayne712222 wayne712222
Moderator | Posts: 165 | Joined: 10/13
Posted: 11/26/13
02:54 AM

wow... nice work as usual..

just wondering.. the patch panel...  could a second one of those be carved up to create the lower section you formed to complete the repair??? for those of us who don't have a sheet metal brake..

CH26373 Lrg

and i took a look... wow... the whole section is available for some years..

CH27778 Lrg  

4zpeed 4zpeed
Enthusiast | Posts: 351 | Joined: 04/13
Posted: 11/26/13
02:19 PM

Hey Mat, I looked this over again and was surprised to see what all I missed last night/this morning. Fabrication is a very rewarding process and an ability acquired over time.

I've never used a "shrinker / stretcher". In the airframe shop we used a metal designated T-0 (T=tensile strength) to fabricate radius parts from forms or other means and then heat treated them via ovens to T-3 or T-6.  
Does the radius get sharper according to the amount of times sent through the "shrinker / stretcher", or how does that work.

If you documented the repair on the quarter sections I would be interested in seeing that as well, I'm sure others would be too. Once again, thanks for sharing.

Poncho huggen gear snatchen posi piro.

idrivejunk idrivejunk
Addict | Posts: 4987 | Joined: 12/09
Posted: 11/26/13
08:04 PM

One day me and the english wheel are going to have a conversation!

Wayne, that dash section could probably be modified to work. The angle should be close but the long bend would be off. The shrinker / stretcher could help with that. The piece actually required modification for use in my case (you'll see) but the important curve and angle were spot-on so I was fairly pleased.

I did see the big cowl plenum piece but figured that was more than I needed although it was tempting. I would want that if I had rust under the wiper transmission area but I don't. The dash itself is the only really expensive piece if I recall correctly. Reproduction pieces are so sketchy fit-wise that I always opt to keep as much original steel in place as possible.

Frank, I don't know enough to learn nobody nothin about metal fab. But I did get a quick tutorial from Mike (its his tool) before first using the shrinky-stretchy. If you youtube lazzemetalshaping and can stand a heavy accent, that dude will show you "how to get the most out of your shrinker-stretcher".

How far into the jaws you place the work is critical. Less metal in the jaws means more curve. And you can curve it in two directions at once. Watch the video, you'll see. The first place I used it was on a section of the Camino quarter that I cut out and welded back in. Had to repair the skin section plus the wheelhouse behind it so I made a new wheel opening lip piece maybe a foot long and repaired the existing cutout section then reinstalled it.

OK that was kind of confusing. I may post pics of that later then since you want to see. I wouldn't want to be guilty of "content flooding" if this stuff is unwanted here. Patching the trunk drop and wheelhouses was an adventure though.

I didn't get the dash welded up today but it is ready. I did make another patch for a roof seam where I had to remove the lead. Tomorrow is weld up and grind day, then off for turkey day.

Heres how the grind went-

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Then paint-

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See those little bends next to the tab? They had to go, this car is flat and notched there instead of bent like that. I sliced and flattened them then welded up the slices.

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Screwed it down and trimmed it next. The gap ended up a little wide on the passenger side but it lines up nice and flush and should weld up just fine. Theres a little control over that once I start welding, the dash can be pushed down a tiny bit to meet the patch.

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Thats it for today, thanks for stopping by. Heres a peek at what I see if I look up from my work. 46 Caddy flathead and suicide-door 33 Dodge. I mostly just work on the muscle-era stuff but these things also make me smile.

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4zpeed 4zpeed
Enthusiast | Posts: 351 | Joined: 04/13
Posted: 11/26/13
09:42 PM

Mat, you must know enough to teach me,(us), something, at least now I,(we), know a shrinker-stretcher exists. I'll look that fella up on youtube. Anyone who does bodywork probably knows the value of that for fabing patches around wheel wells. I'd like to try my hand at that.
"I wouldn't want to be guilty of "content flooding" if this stuff is unwanted here."

If they don't want to look at it they don't have to right? There are some of us that can use all the help we can get.
I could watch 10 people make the same repair and hopefully learn something different from each one. Different techniques and methods are used in different situations and its always nice to get fresh viewpoints.

Remember when you said something about removing a panel to gain access to fix something, I think it was in your GTO thread. That's what I'm talking about, even though I don't want to replace the entire quarter, I want to remove it to reach the inaccessible areas. Appreciate the idea.

BTW, nice view for just poppin your head up, lucky dawg.

Poncho huggen gear snatchen posi piro.

wayne712222 wayne712222
Moderator | Posts: 165 | Joined: 10/13
Posted: 11/27/13
12:56 AM

turn on the flood matt..  everybody learns from your threads..  

Torqued400 Torqued400
Addict | Posts: 2479 | Joined: 10/08
Posted: 11/27/13
12:20 PM

Keep them coming Matt, Your posts are my favorite reading material (and pics).
I can't wait for HPP to do a story on you. Cool  Grin  T  
"We build Excitement"

idrivejunk idrivejunk
Addict | Posts: 4987 | Joined: 12/09
Posted: 11/27/13
08:37 PM

OK then, I'll try to round up the fancy pics from the quarter area patches. Might be the weekend though, theres a lot of pics to upload and resize. Thanks for the kind words, gents. Strap on the barf-bags for the weld pictures, they look like chewing gum but I guarantee the seam.

We knocked off an hour early so I didn't finish but almost. Got the welding done on the dash and half the grinding. The big Miller welder was busy first couple hours so I ended up nursing the little Clarke one to health, enough to do my plug welds. Used the big rig to do the seam. Both have .030 wire in them, but I think a snappy 110V welder with .024 wire would be preferrable for this. Our welders get passed around and ridden pretty hard.

I plug welded the bottom row first. Did not get a pic of the weld holes after final prep with a flat-face spot weld cutting bit, but all the paint is cleaned from each hole before welding. After those, I began tacking the dash to the patch-

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Thats how many tacks it took to get it flush all the way across. I use a butter knife to pry / hold the metal edges flush then tack it. Next comes several hours of slow smoky work, one spot weld at a time and watching for warpage like a hawk. There is a bead of foam-like factory sealant just above my cut, under the dash skin. That catches fire with each weld. The placement of my seam 1/4" down the bed kept me back from that, and its right where the windshield adhesive goes so some irregularities are acceptable as long as the dash stays fairly straight. Ends up like this, and looks are not terribly important.

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Once that was all done, I ground welds the rest of the day. Loud and sparky and with precise aim. Looks like its gonna turn out just fine. Sure will be an improvement, it cost a week's work and a hundred dollar part.

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Of course once I get all that smooth, I'll re-check it for holes and weld as needed. Then I'll hammer work the dash to minimize any warpage that occurred and it will be done. No bondo there is best because the glass mounts there, but it will get primed a couple good times and that should work.

Heres another peek from an adjoining stall, surgery on a 40 Ford cab. I'll feed in the other pics when time allows.
Thanks guys.  Cool

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4zpeed 4zpeed
Enthusiast | Posts: 351 | Joined: 04/13
Posted: 11/28/13
09:38 AM

Sweet lookin product in the end bud, that's a fine grinding job, looks great. Takes patience to produce quality work. One would be hard pressed to find that repair and seems structural integrity was restored as well.

I like those adjustable legs/wheels on that home made work table, they look handy.

Poncho huggen gear snatchen posi piro.

66beaumont 66beaumont
User | Posts: 138 | Joined: 03/12
Posted: 11/28/13
08:59 PM

Well done Matt. I think we have the same skill level for welding, I also spend lots of timing grinding after welding but the important part is the end result Smile .I have most patch work done on my 69,hopefully can hang quarters soon.             btw Beaumont is for sale  anyone want a rare Canadian Pontiac?  
alley find 69goat #'s match 400ys,th400,3:55,249000 miles / 66 beaumont,454,tko500,3:73 auburn ls

idrivejunk idrivejunk
Addict | Posts: 4987 | Joined: 12/09
Posted: 11/30/13
06:32 PM

Thanks, guys. Yeah I should really know better than to show welds on the internet.  Crazy

As promised, here is another chapter in the repair story currently unfolding. This is the part where I cut off a chunk of quarter panel and then weld it back in, so I can make a repair behind it.

She came in looking pretty shaggy. I didn't think it was worth slapping some crummy quarter panel on so I just got a patch panel for that stuff behind the wheel. Thats a whole 'nother chapter there, four layers deep.

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After poking around with a pick, this is where I chose to cut the quarter-

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Cleaned all that up and decided where to cut the wheelhouse-

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Made my piece-

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Welded and smoothed that patch-

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Found a suitable strip of scrap that had been trimmed from another panel's edge then made cuts in it and formed it to the fragile existing steel. I cleaned the old panel in a blast cabinet.

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Then I welded up those cuts and gave the wheelhouse a shot of paint-

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Clamped that new lip to the old wheelhouse and verified the contour from all the angles-

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Sat the old piece up there-

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Trimmed only the bottom edge to fit it back in there, then tacked the two halves together just right-

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Then I welded up the tough seam and took the whole piece back off to grind and paint the backside of all that. This is after I did all that and tacked it back in place-

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Very carefully, I welded it in for good. Plug welds at the wheelhouse were replaced at the original locations. As Frank observed, this type of repair is harder to spot than entire panel replacements. It also restores collision safety and corrosion resistance when no new steel is overlapped and everything is butt welded. Sure, there will be body filler needed. But a brand new quarter would need it too and this one is the original with all it's crisp and properly-fitting edges.

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4zpeed 4zpeed
Enthusiast | Posts: 351 | Joined: 04/13
Posted: 12/01/13
05:49 PM

About the only thing you didn't do was smelt the metal from iron ore. That was fabrication to the utmost. I have to hand it to you, outstanding job, thanks for posting that.

Poncho huggen gear snatchen posi piro.

wayne712222 wayne712222
Moderator | Posts: 165 | Joined: 10/13
Posted: 12/01/13
08:16 PM

to go with the wheel well section.. a friend needed a little more wheel well clearance..

i know this is jacked.. but it worked perfectly..

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idrivejunk idrivejunk
Addict | Posts: 4987 | Joined: 12/09
Posted: 12/01/13
09:14 PM

Frank, I've watched some backyard smelting stuff that looks pretty cool. My place isn't sufficiently rural for that, probably a good thing there. I wish I had discovered the shrinker / stretcher before I made that lip but it still came out fine. Its a lot of fun to fix this stuff, most cars I see just have little hotspots of corrosion and can be fixed this way if preferred.

Wayne, that part where the jack is ... that sure is where they mostly rub. Its a strong spot in the wheelwell. Sometimes you can flatten that lip all day and it still rubs where that jack is, above the flange. I made sure to keep my fixed flange as tight as the original was in that area. Its solid enough to be "massaged" if need be for tire clearance. Normally, replacement wheelhouses and quarters don't fit each other let alone the car so the snip-snip is my favorite approach. At the bottom rear of that wheelhouse was another adventure that I have pics of for a rainy or snowy day. Again, this construction is shared among all GM A-bodies of this generation.  

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