The Stovebolt Site Forums The Shop Area Paint and Body Shop No rear access, patches

Not having any rear access to a repair, in thin metal, in a critical area, is challenging. Here are some areas with no access to back-up a blow thru. The tailgate edge was not possible for me to slide hammer. Too stiff in that area. The tailgate was extremely dented in a deep karate chop crease and associated long dent. 2 places. A "long" and a "short" section. You can see the 1" thick bondo chunk I took out. Sitting on the gate top, white/pink thing. I cut out the dented roll edge section in such a way as to be able to reach in and also straighten out the flat portion. Then work the removed crease/dent piece back to round. I also created an inner backing edge all around the opening. You can see the start of this in one pic (black paint not removed yet) and see the plug welds into this "inner skeleton backer" on the other tacked-on long patch. I can not afford to take a chance and blow thru when almost done, then chase a blow out. When you grind a blow out bridge it sometimes opens up again. Talk about going crazy!!! I'm just not going to fight that anymore on no-access panels. Now I will always add a plug welded backer plate. It's Bartamosity not to.

Maybe some of this will help someone who is frustrated like I was. It all worked very well. As you can see, the process of cutting out a badly creased area and use that piece as the patch, leaves some funky wide gaps. That's another good reason for a backer. You could make a whole new patch but it was easier to get the cutout pieces to fit. You should always consider fixing the dent by removing it and pounding it back to shape, It's faster, if you can believe it. It's already the right size Don't be temped to use a .040 thick angle grinder disc. It will shatter and hurt you. Tried that already. Use 1/16 and keep the cut as thin as possible with that. You can use a .045 3" die grinder disc. That's pretty safe. Less likely to break because less flex, less leverage. Nice thin cut for my reweld scenario.

None of the tailgate is finish welded yet. I'm outside in very high heat and can only work 2 hrs and rest inside. I use cold towels on my head when not welding. Drink lots of water. It is really hot. Unpainted metal in the shade is too hot to touch.

The door had a compound curve and a body line involved with another karate chop dent/crease. This did not have any access either. Just a small peek hole. Dent was again right on a hard to pull crease. I could not bring the removed dented section back to acceptable shape. The only patch available for 60-66 is a door skin. $180 shipped. I bought a donor "fender extension" locally for $12. Exact shape and thickness. Blew thru several times. No backing. You can watch all the videos you want and I've practiced a lot. You will blow thru. But you do learn to fix them. .047-.052 thick material is very hard to weld over and over. I settled on .025 wire with gas. Set on very high and fast. Lots of ideas about the settings and wire diameter. You can't use the chart. You may have voltage fluctuation in a neighborhood, extension cord length, welding cable sleeve wear, tip wear, wire quality, wind, how the metal shape and surrounding area takes the heat, whether backing or no backing, humidity, ground clamp effectiveness, metal cleanliness, your dexterity that day.......you just have to play with the flux capacitor speed and gigawatts supplied plutonium nuclear reactor knobs. Listen for GHUZZZZZZD..... GHUZZZZZZD SCHIZZLE SCHAZZZLE SPARKPOP kind of thing. For 1.06 seconds...and if it welded the thing or not is good too.

There was also a hole in the door (below my upper patch) with a bad patch. It was brazed, You can't MIG on a braze. Had to drill it out bigger. I just loved that. Anyway, no access AGAIN. I made a round patch bigger than the hole. Drilled a 1/16 hole in the middle of it. Fished a wire from outside to an opening far, far away inside the door. Put wire in the patch piece hole, bend it over and pulled the patch back into door and up tight. Plug welded while pulling out on the backer/plug/heat sink wire. Then broke wire off. Fill with weld, grind and filler and sand.

Whenever you are patching, try to cut out the section and have radius corners. Like drill four holes then cut. Like as big as you can stand. Then cut out the patch with matching radius. This eliminates weld bunching/globulation/overheat at square corners. You will do your spot-stack welds more "linear". Curvilinear.

These are not tips from an expert. Just my struggle to survive. It is fun and rewarding mostly.

Then you got your dreaded speaker hole.

The front upper shock mounts on 4X4 always break in two. So made a stronger one from square tubing.

Good work! You’ve been a busy bee.🛠

Wow bartamos you do some nice work. Wish I had your skills.

Anyone can do this. I am just dwelling on thin metal techniques I do. Thick metal is easy. I have a Miller stick and Miller Mig. I don't take pictures of my screw ups.
So to add some more: Don't use air or electric discs to deburr the edges. You can take off .010 on each side in the blink of an eye. Then the edge is down to .030 or less. Right where you are going to weld. Inviting a blow out. Use a hand file with light pressure or a hand edge deburr tool or leave it alone altogether. Hammering on edges will do the same thinning. If you are hammering on dolly, just light taps, just short of smashing .010 material but straightening whatever you are doing.

Thin metal, with no rear access, can not be planished either. So you try to cool each dot with air or wait a long time. Water cooling has it's alleged draw backs. Bottom line is: You will have some warpage. You can't stop it all. It will be way less on small areas, with bends and curves near by, than it is on big flat surfaces.

These guys you see on videos that "bounce around" when welding dots, one area and then another. It's BS. They are better than me but I do ONE at a time. You heat a LARGE area with a weld. If you keep going, albeit "far away", you are still adding heat to the panel before the other heat cools. We only have one truck and one panel to fix. We are not in a hurry and can not afford to warp it. If you warp, you are done, you are sad, you are in deep trouble with the whole project. You have a disaster. You don't want that. Don't pay any attention to someone showing to "move around as you go". Especially on small patches. It's BS!!!! Maybe it will be OK. Who knows? The risk is disaster that can't be fixed by us mortals.

Any thoughts on trapping moisture at the sheetmetal sandwich area?

Hi Mark. I was still typing about warpage above. Do you mean, by sandwich, the backing pieces I add with plug welds?

Yes.

That's probably a huge discussion I don't want to start. There is no moisture where I live. We never think about rain, humidity or salt here. That's why everybody buys vehicles from AZ and CA. Not much rust. "Trapping moisture" can be defined by different people in different ways. I really don't know the science behind or the different definitions of "trapping moisture".

As far as in general though, liquid water from leaks is one issue. Standing water is not good. Condensation is another source of water. Condensation can form anywhere. Most areas that can accumulate liquid water have a drain method built in. Drain holes. Condensation has to evaporate by breathing and by heat. Metal does not absorb water. So the water forms on the surface and starts to rust if it does not evaporate. I equate my particular backing pieces to the many pinch welds there are on my truck. The tailgate inside can breath and drain due to holes and openings. I don't really have a definite answer as to what will happen in time. I know as far as in AZ, it will not rust more than oxidize slightly. The truck came from Grass Valley, Ca. It has very little rust. It is 58 years old.

I think I started letting go of my worries when I replaced the drivers side cowl on my '51. The bottom was rotted out, but at the seam, where it is "sandwiched" and spot welded, I figured it would also be rusted and easy to take apart. Boy, was it a bear! My car was an AZ car but had the opportunity to have fine dust and dirt settle in those lower areas. Which then trapped moisture. So, lesson learned was to coat as much as I could with epoxy before welding together. Then, make it regular maintenance to keep the drain holes clean.

Good info Mark. In all honesty, it's hard for me to worry about moisture when you can fry an egg on the sidewalk.