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Old 10-01-2022, 05:41 PM   #1
FAKKY
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How to fix this - after patch panel

Hey guys
I had bad rot in the doors and decided to cut them out and replace with teh lower weld in units.

https://www.classicindustries.com/pr...B&gclsrc=aw.ds

So when I patched these in ......... looks like I now have this issue. Basically the metal above the weld is kinda bowed out (almost like its too long). I know theres various ways to shrink metal and assuming I have some hammer/dolly work here ... but just not 100% best way to approach as never done before.

Up for thoughts.
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Old 10-01-2022, 05:52 PM   #2
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Re: How to fix this - after patch panel

another pic but hard to get a good one ......
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Old 10-01-2022, 09:56 PM   #3
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Re: How to fix this - after patch panel

the blue lines are new welds in the outer door skin, and it was during those welds the problem was made? And there was no hammering done on panel at all yet?
Welding shrinks metal, sometimes the results in a panel look like the panel has too much metal, but have faith in that simple fact, your welds shrank. The panel above may be bowed out, but because the shrunk section below is pulling the surface. like squeezing a balloon.

If the first two sentences are a correct assumption I'd start by grinding those weld beads down, then hammer on dolly to stretch the weld seam. It does not take much. lots of little taps are better that walloping it like your driving nails. Work your way inwards along the weld and watch how the metal responds. The corner you show in the weld bead is going to be the tricky bit, and it is probably why the warp extends up into the centre of the door skin uneaveny.
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Old 10-01-2022, 10:28 PM   #4
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Re: How to fix this - after patch panel

exactly what Lee said
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Old 10-01-2022, 10:30 PM   #5
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Re: How to fix this - after patch panel

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the blue lines are new welds in the outer door skin, and it was during those welds the problem was made? And there was no hammering done on panel at all yet?
Welding shrinks metal, sometimes the results in a panel look like the panel has too much metal, but have faith in that simple fact, your welds shrank. The panel above may be bowed out, but because the shrunk section below is pulling the surface. like squeezing a balloon.

If the first two sentences are a correct assumption I'd start by grinding those weld beads down, then hammer on dolly to stretch the weld seam. It does not take much. lots of little taps are better that walloping it like your driving nails. Work your way inwards along the weld and watch how the metal responds. The corner you show in the weld bead is going to be the tricky bit, and it is probably why the warp extends up into the centre of the door skin uneaveny.
HI leegreen
Yes sorry I have should have made that more clear in hindsight.
The blue lines represent the rough path of the welds/patches.
The red resembles the worst section of the "bow out".

Being my first time - when I was creating the patch with the lips for the door edges - I was just really focused on getting somewhat straight on the edges and wasnt really paying attention to much else ... then wherever the edge of the patch was in the main section of the door skin I just cut along that and welded it in.

No hammering or dolly work.

Do I need to heat the metal after I grind down ?
Also since the entire is sealed up assume I am going to have to cut the inside door to gain access to the rear for a dolly ...... but then when I weld that up - wont I have the same issue on the inside ? But I guess thats less noticeable/important than the outside ?

thanks !!
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Old 10-01-2022, 11:23 PM   #6
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Re: How to fix this - after patch panel

you want to try to grind without putting a lot of heat in, that would shrink it more. I'd use a new grinding stone/disk with a square edge and use that edge to carefully take off the bead. Your not trying to get it real smooth at this point just flat enough to hammer.

No reason to heat the seem after grinding. More heat = more shrink.

you need a dolly in behind to hammer on to stretch the seam. Gonna have to open up the back if there are no access holes. I'd consider making a permanent access hole with a screw on cover so you can get in there with a paint brush. All this welding will rust away in no time if not sealed up.

The real trick to this work is to keep the heat to a minimum. Weld a spot at a time keep moving around the panel and let it cool, some people use wet rags, some an air line. Both work. So does working outside in the winter
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Old 10-02-2022, 12:54 AM   #7
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Re: How to fix this - after patch panel

did you mig weld the panel? mig welding doesn't love to be hammer on dolly too much after it cools off, it tends to get hard and crack if too much work is done. there are softer wire alloys that can work a bit better than others
if cutting a hole on the inside you could tack some flaps onto the door and then screw the cut out piece to that. not much heat generated that way. if you wanna weld it back in then do small welds, one here one there but not close together so the welding heat will be more spread out. let the panel cool to room temp between welds if they start getting close together. like wait till you could put your tongue on it. I find having another job to do between welds is a good idea. wait now, or spend that time later doing body work.
weld, hammer on dolly when still hot, like red, that stretches the metal. it cools and shrinks back to a more normal size.
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Old 10-02-2022, 08:02 AM   #8
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Re: How to fix this - after patch panel

good tips thanks - yes I did go pretty much as quick as I could with the welding and yes mig - just enough time between tacks so it didnt blow through the metal.

Good tip on the access hole for paint as well as dolly too.

So just to be clear - this should still be fixable with hammer and dolly ? Just feels like a lot of extra metal that has to come out/level out ..... to get more level ...... This is absolutely not a show car (DD) and obviously can smooth stuff out with body filler just trying to not have to have 2" of body filler to get it done.
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Old 10-02-2022, 11:06 AM   #9
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Re: How to fix this - after patch panel

if you were to throw a straight edge across the low spot, how much variation is there?
I guess there is nothing to lose in trying, it will come out some or it won't. the bad is if you end up with a deep layer of bondo on a door. doors vibrate a lot when slammed shut so dondo will tend to crack or fall off after awhile.
hammer and dolly with hammer right on the dolly. this will stretch the weld as much as possible. try to grind it smooth on both sides first so you don't just hit the high lumps. I like to use a thick cut off wheel for this as it grinds with less heat. I also use a burr on a pencil grinder for the spots where an angle grinder or cut off tool doesn't fit in. I have used a course flap disc as well but you need to keep in mind the heat generated by whatever you use or it will make things worse. when hammering you should hear the dolly ping each time so you know you are hitting it. try not to vary off the weld so you stretch the steel in the area next to the weld. this is what they call the HAZ, heat affected zone.
I know you don't wanna hear it but next time start by getting the paint and rust etc cleaned off both sides of the steel. clean that with acetone or something like that to get super clean steel, then place your patch part-also cleaned the same way- and just do a whole bunch of tack welds, about 2 inches apart and allowing things to cool off between tacks, and then when you have the full length tacked together go back and put another tack in between each of those first tacks. same process. then go back and put a tack between those, same process. keep doing that till the tacks are close enough together to allow a short weld to connect the tacks. when you do this ensure each tack has been cleaned off so no contaminants are present. I simply use the cut off tool wheel. I usually have a few types on hand-thin ones for actually cutting, and thicker ones for grinding. I know somew guys will keep a wet rag closeby to quickly cool the welds or use compressed air. be careful with this as it can also make the weld area harder and that makes it tougher to work later.
just my thoughts
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Old 10-02-2022, 11:59 AM   #10
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Re: How to fix this - after patch panel

Thanks - yeah thats the part Im trying to decide. Cutting out the inside door for an access hole to dolly ..... or just ripping the entire patches out and making a bigger 1 piece patch I did that on the other side and was no where near as bad. I do remember having issues blowing through metal here ....... so had to build up a lot of areas with a lot of weld/heat.

more pics

brown painted door to keep rust off is the 1st one I did months back
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Old 10-02-2022, 12:06 PM   #11
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Re: How to fix this - after patch panel

the last pic with brown paint is my 1st door which still not perfect is much better with no large bowouts. I used a larger 2 piece of patch .... rather than 4 smaller parts .....

If I was to cut this all out and start over ........ do I follow the same appraoch just being more careful of heat. Meaning how I did it was.....

1 - cutout across the bottomn of the door where it felt thin/had holes.
2- starting from left to right I cut out the rectangle patches you see just a bit larger than required. I bent the door edges and fitted then onto door the pushed the top metal to the original door skin and tack welded in a few spaces.
3. I then cut along the edge of that panel and welded the gap as I went so a flush weld not a butt weld.
4. Continued for other 4 pieces.

1 issue I know is that the metal (patch) was mostly straight. So when I pushed it in to tack weld to the original skin it was under some light pressure meaning it naturally wanted to pull the door skin away. Im sure that added to the issue along with the heat.

I can try and bend a bit better over some 4" pipe or something but seems rally hard to get the original shape also.

.....

So kinda leaning to just cutting it all out .........
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Old 10-02-2022, 12:30 PM   #12
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Re: How to fix this - after patch panel

Also find this confusing - hes adding heat into the weld via shrinking disc

https://www.youtube.com/watch?v=rJLrVaa1o1w&t=100s
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Old 10-02-2022, 01:55 PM   #13
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Re: How to fix this - after patch panel

Welding sheet metal can be tricky. I typically have a bucket of water and a rag handy for cooling down welds. A rag stapled to the end of a paint stick keeps the welding gloves dry.
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Old 10-02-2022, 02:00 PM   #14
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Re: How to fix this - after patch panel

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Welding sheet metal can be tricky. I typically have a bucket of water and a rag handy for cooling down welds. A rag stapled to the end of a paint stick keeps the welding gloves dry.
Yeah learning that the hard way now
Going to cut it out but the only sheet metal I have on hand is 16 ga .... hmm
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Old 10-02-2022, 02:08 PM   #15
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Re: How to fix this - after patch panel

A shrinking disc does add heat..lots of it..when it heats the metal, it expands it, and you cool it fast, it shrinks it to less than before you started ..
A trick I learned when I was doing some large seams was to keep a air nozzle in you off hand when welding...as soon as you make the tack ,you hit it with air to col it off as fast as possible
And all you want to do it small tacks..move around and let cool before making another..
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Old 10-02-2022, 02:12 PM   #16
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Re: How to fix this - after patch panel

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A shrinking disc does add heat..lots of it..when it heats the metal, it expands it, and you cool it fast, it shrinks it to less than before you started ..
A trick I learned when I was doing some large seams was to keep a air nozzle in you off hand when welding...as soon as you make the tack ,you hit it with air to col it off as fast as possible
And all you want to do it small tacks..move around and let cool before making another..
Was just watching some videos on that from fitzee/bad chad.
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Old 10-02-2022, 04:20 PM   #17
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Re: How to fix this - after patch panel

If you're going to start over, you might think about using some ER70S-7 welding wire in your MIG. ESAB sells it as "Easy Grind" You should get a little flatter bead and be easier to grind.

As far as technique it is pretty tedious. I'll normally spend an hour or two with a die grinder and a hand file getting the fit-up as close to line-on-line as I can get it before I start welding. Start with tacks about 1.5-2" apart, and after each round of tacks grind the welds flush with the edge of a cutoff wheel in a die grinder and planish them with a hammer and dolly (hammer-on) to stretch the metal and bring it back into contour between welding rounds. Keep welding, grinding and planishing till you've connected all the dots. The dolly will always be inside the door cavity and you should be able to reach all of the weld through the regulator access panel. Take a strong light on the back of the panel and looks for spots you've missed - you'll have a few to fill.

In my opinion, MIGing a patch panel is always a little dicey - you add a lot of heat to one spot that cools very quickly and hardens the metal, making it difficult to grind and planish. You end up with a mis-mash of hard and soft spots that's difficult to bring to contour - so you drag out the bondo and call it a day. This is especially true for long, low crown areas like the bottom of the doors

A better way is to get a near perfect fit-up so you can tack without filler with a gas or a TIG, planish the tacks so there's no steps in the butt joint, then TIG or gas weld it in one go. When you're done the metal is uniformly annealed and much easier to grind and dolly to contour.
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Old 10-02-2022, 06:31 PM   #18
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Re: How to fix this - after patch panel

It may be easier to cut off the bad patch, clean the area nicely on both sides of the metal so no contaminants get sucked into the weld, then fit up a new piece, one piece patch is better, then do the tack weld technique and take your time. Maybe less time spent and get a better result.
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Old 10-03-2022, 08:09 AM   #19
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Re: How to fix this - after patch panel

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It may be easier to cut off the bad patch, clean the area nicely on both sides of the metal so no contaminants get sucked into the weld, then fit up a new piece, one piece patch is better, then do the tack weld technique and take your time. Maybe less time spent and get a better result.
Cut it out yesterday and was conisering the 16ga when the welder blew. Sounds like an internal gas line .... will have to look and order a part or new welder.
So on hold.

I think this was the right move ....... Ill try and a cut and preform a piece that fits good prior and take a lot more time getting it into position correctly and hammer/dolly/cool as I go etc.

WIll psot an update but might be a while given ^^
thx all
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Old 10-03-2022, 09:38 AM   #20
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Re: How to fix this - after patch panel

16 gauge will be hard to shape and stiffer than the rest of the panel your joining it to. I'd give that a pass and get some 18, or even 20
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Old 10-03-2022, 09:45 AM   #21
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Re: How to fix this - after patch panel

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16 gauge will be hard to shape and stiffer than the rest of the panel your joining it to. I'd give that a pass and get some 18, or even 20
thx yeah bought some 18 since my welder is down.


quick side question ...... regarding painting of the inside panels ......
Generally speakin AFTER I had done bodywork and painting the exterior - I was thinking of getting a series of scrubbing brushes with flexible handles and using something like corrseal or even straight phosp acid to treat the inside panels with a mixture of spray bottle and brush.

Thoughts ?

I really dont want to introduce acid anywhere prior to the exterior paint as worried if not cleaned properly will impact paint.


eg spray using a pressurized sprayer ......... from, access holes .....
then scrub with a tube brush or similar parts I can access

https://www.justmanbrush.com/36-inch...IaAqF0EALw_wcB


thoughts ?
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Old 10-03-2022, 10:03 AM   #22
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Re: How to fix this - after patch panel

So the welder, I assume it's a mig with gas hooked up? If you shut off the gas bottle the noise stops? Or does It only make noise when you pull the trigger to weld? Can you tell if it is making the noise inside the welder's metal box or somewhere else?
From what I recall the tank supplies gas to a solenoid valve which only allows gas flow when you pull the weld trigger. Then gas flows from the solenoid out through the mig hose to the tip.
Anyway, hopefully you can fix it cheaper than buying a new one.
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Old 10-03-2022, 10:07 AM   #23
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Re: How to fix this - after patch panel

I'm with Lee Green on the gauge of metal. 18 ga would be easier to work or possibly even 20ga.
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Old 10-03-2022, 10:07 AM   #24
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Re: How to fix this - after patch panel

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So the welder, I assume it's a mig with gas hooked up? If you shut off the gas bottle the noise stops? Or does It only make noise when you pull the trigger to weld? Can you tell if it is making the noise inside the welder's metal box or somewhere else?
From what I recall the tank supplies gas to a solenoid valve which only allows gas flow when you pull the weld trigger. Then gas flows from the solenoid out through the mig hose to the tip.
Anyway, hopefully you can fix it cheaper than buying a new one.
Yeah was weldign an hear a loud pop from the bottle/machine area.
Turned eveything off then opened the valve thinking maybe a crack in hose - but the bottle to welder hgas line was fine.
Leak comming from inside.

Guessing something cracked or popped off a fitting inside joining the incoming gas line to the mig torch.
Will need to pull apart today and see.
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Old 10-03-2022, 10:12 AM   #25
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Re: How to fix this - after patch panel

Sounds like a hose came apart inside. At least it should be a cheap fix. Do you have a hydraulic hose shop anywhere close?
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