Project Big Red

[Greg5OH]

hey that panel looks great! little bit of filler along the seam and it will look like factory.

I too never know exactly how to put in a patch panel. If you put a step in it so there is metal behind the seam, then that part behind the original skin is never attached to anythign nor does it have any corrosion protection.
doing a butt weld, well then you have ot be careful as there is nothign behind there.
I should take an autobody class one day..Save alot of headaches i think.

 

[IDIoit]

I should take an autobody class one day..Save alot of headaches i think.

unless you plan on doing autobody for a living, i would not waste the time and money.

as in everything, text book and the real world are two totally different monsters.

most of the learning curve in this department is equipment and prep.

another common mistake is not letting the metal cool.

all metal work on the exterior of a car will need filler, really no way of getting around it.
unless you are a bad@$$

if you want to learn more, i suggest you practice practice and practice some more.

this guy, makes it look easy. he has alot of time under his belt and did an excellent job!!!
http://www.oilburners.net/forums/showthread.php?71759-Tin-bashing&highlight=patch+panels

 

[Greg5OH]

i need to knwo the proper technique before p[racticing though.
I can perfect the craft of botched panels!

I assume, to do it properly, if you can get access to the back side of the panel you jsut welded in, you have to cut out the panel from the inside to get access to the outer skin, and weld that, and paint it. Then replace the panel you cut out, am I right?

heres a quick MSPaint drawing

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So we make a step slip to put up behind the original good outer skin. But then there is an open flap from the inside of the outer skin. Do we cut out the grey inner panel from inside the vehicle to seal up the lap joint we created?

 

[IDIoit]

as i never went to school for anything automotive,
i opted for OJT.
ive worked for a few different fab shops in the area.

i was taught that if you have a panel with a separate inner structure you use a rust inhibitor
on the interior to prevent rust.
then you but weld the replacement panel.
using a lip like you drew may help the welding process, but it does give moisture a place to rest and will rust quicker.

when welding thin metals such as 14 gauge or less, the weld will penetrate.
the major trick to but welding is prep work.
making your patch panel fit exactly to the metal youre trying to replace.
i am no professional, but i have done alot of patch panels.
i always but weld, i never use a lip.

 

[Greg5OH]

thanks good to know. Indeed, having a perfect butt joint will have a nice area to weld and no gaps to try to fill with weld.
My issue is also my 220v harbor freight welder is too hot for body work! Really need to get a tig for the upcoming stainless and aluminum welding I will be doing. And no doubt it will be a huige help with auto body work.
Tack it in with a mig then finish it with a tig. Or at least get a good mig welder with fluid current adjustment

 

[laserjock]

The problem with lap welding is you always end up with a lip that you can't do much with. I'm sure it would make it easier to weld but if you get the panel fit right with the correct gap, the butt welding is not really any harder than the lap weld. You can apply weld through primer in those areas but as for corrosion protection, you don't have many options if you cant get to it easily and even if you can get to it its lapped so you cant get anything to the actual weld spot and that is where it will rot out. This I know from experience. If you but weld at least you have a chance of getting something on it that's a little better than some weld through primer supposing you can get to it. Myself, I cut access holes from the inside so I would be able to get something in there. So really, to me corrosion resistance is the main reason to butt weld over lap weld. In the case of a floor pan, I think it's much less critical. I lap welded in the big pieces but I also seem welded on the outside not just spotting them to seal it up from the under side. The lip is on the inside and I will probably seam seal or shoot paint in that gap as best I can because I can get to it reasonably well.

Take that for what it's worth. I don't think there is a one size fits every situation here. You just have to decide based on your circumstances and ability what the best course of action is.

 

[IDIoit]

my 220 lincoln 180 HD works great on sheet metal, i have 5 heat settings.

TIG welding does take lots of hardcore practice,
The reason people TIG sheet metal is because it makes the metal workable.
the weld is mailable. unlike MIG where your weld is hard and brittle.

use one or the other! dont mix the two.

most of the time a mig is just fine, when chopping a roof a tig is the preferred method so that you can metal work the finish product.

how do you TIG the panel in while trying to hold the work, hold the torch, and hold the filler rod?

CLAMPS!!! ive also tached one side in and manipulated the small fusion weld to get it into place.
magnets work great too, but it does mess with the arc of the TIG if you get too close.

 

[Dieselcrawler]

Or spot tig without filler for to hold then use filler rod to finish

 

[laserjock]

One last piece to go. Remember I had to cut this thing into 3 pieces and it still didn't fit. So I hunted for this piece for 45 minutes. Yes it was in the second or third place I looked after I had been all over the garage and came back there again. [emoji35]

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I then I ended up throwing it away anyway because it fit like crap. Completely the wrong shape. I cut the lip off the old piece cleaned it up and then hit it with some weld through primer.

While I was waiting for the primer to dry, I got down one of the OBS quarter windows. There's not a lot of documentation on swapping them and I'll do a full write up once I'm done but here is a preview. The OBS window looks like this.

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The big difference is that the old style glass is sandwiched between the outer metal frame and the cab. The OBS window is a single piece unit. You can see it has studs sticking out the back.

And here's what it looks like installed.

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Yep it drops right in the hole.

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The studs sit just inside the opening. The washer nuts grab the inner lip of the cab metal and will tighten down pretty good. The reality is that you probably wouldn't have to make any modification at all. Just apply sealant and snug the nuts up. I'm sure the sealant is doing most of the work holding it in. I'll probably weld a few tabs in to make me feel better. Like I said, I'll do a tech with lots of pics once I finish it off.

Back to the other project.

Got it all welded up and I should be able to put some stuff on the inside for corrosion protection through the holes I made. I didn't take a picture, but the inside seam doesn't look too bad. I also filled a bunch of pin holes. I'll work it all down again and move to the other side.

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So progress is happening. Hood shipped today so I now have all the body metal. Rock auto had a capa certified part and I used the 5% off which wasn't much but better than nothing.

 

[junk]

Looking good man. Good plan using that lip off the old panel. Always amazing how good and bad replacement panels can fit.

-Jeremy

 

[TahoeTom]

To grind down welds use a cutting disk on edge on your die grinder. You can concentrate on the high areas until it is just proud of the surrounding metal before switching to a sanding disk. You can see what you are doing as the work isn't hidden by the disk and you can avoid excessive thinning of the surrounding metal.

 

[laserjock]

That's a good idea. Esepecially on the big globby sections. Switching to 2" roloc disks helps quite a bit with the control aspects. The flap wheel on the grinder is good for working a lot of weld down fast but like you said, if you aren't careful you can dig a hole pretty quick. It's more forgiving than an abrasive disk but still really aggressive.

 

[sjwelds]

To grind down welds use a cutting disk on edge on your die grinder. You can concentrate on the high areas until it is just proud of the surrounding metal before switching to a sanding disk. You can see what you are doing as the work isn't hidden by the disk and you can avoid excessive thinning of the surrounding metal.

This is a good idea. A couple of things I would watch for tho:

Do not get too heavy-handed when grinding with a cutting wheel. Too much side load and the wheel flies apart. Most die grinders will spin at ~20,000 rpm. That means pieces flying everywhere should a wheel explode.

Also, don't get too close to the base metal. The "round" of the wheel will leave a "valley" right in the middle of where you've ground. Make sure that valley isn't so deep as to cause problems later.

 

[IDIoit]

FWIW, every time i do patch panel replacement, i buy 3 new flapper wheels.

40 grit
80 grit
120 grit.

i use the edge of the 40 grit to knock down big stuff, and then hit it with 120.
sometimes use the 80.

a worn wheel has no edge, but a new wheel does!

a cut off wheel works too, but ive seen these things do alot of damage, i dont need one imbedded in my face.

just becarefull!
shes looking great!
you should be driving her "tomorrow"

 

[laserjock]

FWIW, every time i do patch panel replacement, i buy 3 new flapper wheels.

40 grit
80 grit
120 grit.

i use the edge of the 40 grit to knock down big stuff, and then hit it with 120.
sometimes use the 80.

a worn wheel has no edge, but a new wheel does!

a cut off wheel works too, but ive seen these things do alot of damage, i dont need one imbedded in my face.

just becarefull!
shes looking great!
you should be driving her "tomorrow"

You're funny.

I switched to a full face shield after getting steel in my eye a year and some ago while grinding with good safety glasses on. Wheel to the face is fairly unlikely but just as unpleasant sticking in the arm or leg. . I have had a couple come apart.