How far do I need to cut to get to good metal to weld?

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JeffisOld

JeffisOld

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Hi folks, I repairing the area just below the tail light on a 69 Dart. I have a little rust out but I am not a body man so I need help knowing how much to cut out. I plan to weld in good steel and use epoxy primer outside and POR 15 inside the trunk and cabin area. Probably under the cabin area also up to the firewall. I will have it on a rotisserie for that in a few days or so.

area.jpg


This is from outside

outside.jpg


This is viewed from in the trunk

inside.jpg
 
Sorry, that was a pretty STUPID post.

My apologies, engage brain before fingers!!!
 
JeffisOld said:
Sorry, that was a pretty STUPID post.

My apologies, engage brain before fingers!!!
Click to expand...
Instead of removing rusted metal in chunks and small parts until you get to quality base metal, look over what is crap and see if your better option may be removing a larger section and fabricating replacement part. Drilling out factory spot welds with either sporweld remover or a drill bit isn't that terribly difficult. As a bonus those holes made by drilling spot welds out gives you weld attachment areas. Sometimes you may find good metal with a pin hole or a large gap requiring filling. If you use a piece of brass or copper as a backing piece while welding, it will help fill that gap/hole easier with less heat and distortion. The copper or brass isn't weldable so weld wire/stick will not "weld" to it. Additionally the cool metal will solidify the molten steel to help fill the gap quickly. Another trick is to use 7018 or 6010 1/16" welding rods with the flux removed (smack it with a hamner a few times and it strips off easily but do not remove the fine flux still adhering to the rod) as filler rod. While mig or stick welding use that as filler material utilizing your none stinger hand to feed it into the arc.
Probably way to much info but hopefully made your project easier.
 
I have used a filler while mig welding in the past. Never thought anybody else would consider it.
 
I had a guy teach me how to use some heavy wire as a filler when working on my frame connectors. That's an awesome trick and stuff like that is GREAT for a newbie like me. This is my first frame off (sorta) restoration and I appreciate the tricks from those more experienced.

Thank you! I need to get some copper or brass and try that.
 
The piece of bronze I use the most is 2"x3"x1/4" with two corners 90°. Another corner is rounded lightly about 1/4" and the other corner rounded about 1/2". Depending upon the job I'll use whichever corner works best or if I'm able to I'll use the piece behind the piece to be welded. This weekend I needed to fill a 1/4" x 20" gap on a 1967 El Camino quarter. I couldn't get behind the quarter so i lightly wedged the sharp 90° into the gap starting my arc on the bronze piece where it touched the base metal of the quarter then running the bead over to tack to the other side of the gap. Jumping around to avoid hot spots. Took about 15 min until each tack was about 1" away from the next...quarter panel maybe 100°F. Let it cool about 15 min then filled in between each tack until only 1/4" between tacks. Let cool again then filled in between every other gap. Cooled then welded. 100% seal welded with no distortion. You'll see after you screw around awhile. Don't overheat...warm to the touch. BTW gas is best for shielding but if you have to use flux core wire be sure to neutralize the acidic flux with TSP (Trisodium Phosphate). Buy a box of TSP at a hardware store and mix per instructions. A cup of liquid mix will go pretty far. Another F'n Old Guy trick.
 
Wristpin said:
The piece of bronze I use the most is 2"x3"x1/4" with two corners 90°. Another corner is rounded lightly about 1/4" and the other corner rounded about 1/2". Depending upon the job I'll use whichever corner works best or if I'm able to I'll use the piece behind the piece to be welded. This weekend I needed to fill a 1/4" x 20" gap on a 1967 El Camino quarter. I couldn't get behind the quarter so i lightly wedged the sharp 90° into the gap starting my arc on the bronze piece where it touched the base metal of the quarter then running the bead over to tack to the other side of the gap. Jumping around to avoid hot spots. Took about 15 min until each tack was about 1" away from the next...quarter panel maybe 100°F. Let it cool about 15 min then filled in between each tack until only 1/4" between tacks. Let cool again then filled in between every other gap. Cooled then welded. 100% seal welded with no distortion. You'll see after you screw around awhile. Don't overheat...warm to the touch. BTW gas is best for shielding but if you have to use flux core wire be sure to neutralize the acidic flux with TSP (Trisodium Phosphate). Buy a box of TSP at a hardware store and mix per instructions. A cup of liquid mix will go pretty far. Another F'n Old Guy trick.
Click to expand...
Excellent description, sir.
 
Thank you Wristpin for taking the time to explain it.

At this rate I may learn enough by the time Dottie is done to teach someone else!

I am using a Miller 130 xp. From what I understand it's biggest liability is that it has only 4 available voltage settings.
 
I did some thin material welding with my old old mig (thats 2 migs ago) that only had switches for setting heat.
Learning the limits of the metal is key. Start low and work your way up. Wire feed will make up for some issues but not all.

Copper block for backing is your best bet,it draws heat the quickest.
Compressed air will aid in cooling the HAZ (heat affected zone) and will aid in the event of a flare up.
I usually blow the fires out,save the water if it gets out of hand.
Oh,a pail of water and a rag Should be handy when welding anything.

Practice before starting on your actual panel, finding a comfortable work position makes a huge difference in your welds too.
 
I'm glad it makes sense. Between the cartoons and **** running around in my head I'm shocked it's legible. Your xp is going to do 90% of what you desire. You may trip breaker on #4 power...a few 6" long penetrating welds on 1/4" thick steel and breaker will start tripping. For auto body you'll probably want power 2 with 30-35fpm wire speed. Start at 40fpm and decrease until wire isn't overfeeding. This will help prevent "blow through". It's time consuming but don't weld on the body more than 1/4" long bead at a time. On the area you're working there's probably alot of overlapping areas. Clean the areas between overlaps as GOOD as you can. Tight fitting overlaps will save your sanity. Get a box (25-50) of #6 screws and use a bit to make a hole that the screw can tighten fairly hard. I use multi stepped bits so the panel where i start my weld is larger than the other hole. Less welding and heat. If you have C-clamps or C-grips they make many jobs easier, cleaner, faster & professional. Anyway...once your piece is trimmed and fits well drill one hole then run the screw in and tighten it. Do several holes like that in different areas to hold your piece in to your liking. Now drill another hole 1/4"-1/2" away from each of those holes then tack those holes...mind the heat. Then pull one screw at a time and tack it shut. Ok...the short distance...1/4-1/2" is for intricate or smaller pieces. Say you're doing a quarter patch panel...those screw distances may be 12" apart (after the first 3 or 4 to align panel) then between each 12" span then between each 6" then 3" then outer panel hole then tack. If you'd like a few pics I can send or post them. I have exposed welds yet on this El Camino of different types. Damn I'm long winded today.
 
Another trick with fixed tap machines is to manipulate the arc with distance and orientation. For doing sheet metal though that's pretty much impossible as it's just a quick zap. As long as your distance and trigger time are consistent you'll be fine.
 
If you can get at both sides,these work well.
A834C8FF-3867-4B8F-95EB-5A4E78EB24AC.png
Made a few with scrap tubing and threaded rod.
 
You guys are awesome!

As an old man who's never done this before I really appropriate you folks taking the time to teach.

Since I have worked on helicopters and airplanes most of my life I am familiar with my metal guys repairing drama g e around the world. I am fortunate enough to have a few hundred Clekos and have come knowledge of how to use them.

I purchased eight of the clamps shown above by Tooljunkie from Eastwood. I am sure in other places they will be useful. The Brass idea is killer as I have a whole lot of trim holes to be filled.
 
Clekos are awesome. My friend’s father owned a few aircraft and spent many years rebuilding all kinds. Lots of equipment and a few skilled employees.
Steel is much more forgiving,so dont shoot for perfection. Thats what filler is for.
 
Since its behind the bumper the easy way is to cut all rust out and over lay your patch a 1/16 and burn away..
But weld is better but harder for a novice welder.
 
I have found a piece of brass approx 2" in diameter and hexagonal shaped. It's about 4" long and weighs approximately a pound. I've used it as a bucking bar for solid rivets but it is absolutely the cat's meow for sheet metal welding.

brass bar.jpg


Thanks for the help gents.

I still need a whole lot of practice though!
 
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