Working with Metal
 

<TABLE width="100%" border=0 itxtvisited="1"><TBODY itxtvisited="1"><TR itxtvisited="1"><TD vAlign=top itxtvisited="1">After several postings under the heading "metal work", I thought it might be helpful to suggest a sticky on the subject. I suggested such to our moderator and it was met with acceptance.

Most importantly, this is intended as a BASIC overview for a beginner. There will be MANY variations on the themes here and more expereinced persons will have learned faster, maybe better, certainly different methods to do the same things. Please, add your expereinces and comments!

Damage repair:
You first task in panel repair is making the decision to repair vs. replace a damaged panel, taking into consideration how long it would take to replace a damaged panel and repair the surrounding panels, including cutting, removing, cleaning, fitting, welding, repairing welds and final panel beating, filling and paint prep. If it's faster to repair (a topic all it's own!), then let's move on.

The general thinking behind repairing panel damage is to "undo" the damage. By that I mean you need to work back from the impact - large to small. A good beginning is to gain access to the area to be repaired. Remove all trim and parts required to have full access to the front and back of he areas needed to be repaired. Don't think it'll be faster to work "around" something - it rarely is!
Generally, always begin with your larger surfaces (and tools) and work to the smaller. As described below, by bumping the large low-spots up from the back - and tapping the high-spots from the front, you can slowly move the metal from high to low to even out the panel.

Rust & panel replacement repair:
First thing to repairing heat-damaged (warped) metal is understanding what happened in the warpage. When you weld you add enough heat in a small area that causes a shrinking and a little heat in a large area that causes a bowing. The weld itself (mig) ends up quite a bit harder than the sheet metal. To work it out, you have to find the high and low spots, stretching out the areas that have shrunk due to the heat, shrinking areas that have expanded and often working the hardened MIG welds back inot the shape of the panel.

This is usually easy enough by running a flat hand (gloves are good!) over the metal and/or spraying a light coating of something from a spray can (flat black?) and running a long block sander over it quickly. Starting with hammer and dolly, bump the low spots up (at first gently) from behind (with the large, gentle parts of dolly first) while tapping down the high spots. This transfers the highs and lows to get the panel flatter - or rounder - depending on the end shape desired. Once you've worked the metal to get it as good as you can, repeat the (light) painting and block again. Once the high and low spots are quite small, use the progressively sharper parts of the dolly, with harder blows with the hammer. If you end up with any "oil can" areas, the metal is stretched and will need a shrink. Do this by getting the high spots hot with a torch (keep it small and do it quickly), quench with a wet rag, then working flat with your hammer & dolly. You should be able to work it until it's flat enough that any low areas would only require a thin skiff of filler. You can't get it "too good". The best bodymen use NO filler! But once you get it very close to the original shape (may take hours), you can grind it all clean and move on to the filler stages.

Again, there more variations than there are pople who do body work - if you have some experience, please share it and make this post even more helpful!
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Excellent idea and post.

Thank you. :)

ok i have never done any paint and body work really and i want to do all of it on my project truck. so i am trying to get all my tools i need first befour i start. there are a little bit of rusted out spots on my truck that will need to be replaced. my question here is will i be able to use a arc welder for it?

I believe the answer would be no as the heat is too high and would warp your panels even if stitched around. I watch an ex_Navy Seabee do welding work around the Hornet every weekend. He is a whiz with an arc welder and acetylene torch. Even with thicker steel than we have on our trucks there are somethings he welds spot by spot instead of a continuous bead. That tells me that an arc would be too hot for our gauge steel.

ok than i guess i wont use a arc welder.

Your best bet would be to purchase a Hobart, Lincoln, or Miller mig welder.

I have a Hobart Iron Man 120. I love the thing to death but it runs too hot to do bodywork unless your very carefull.

i have used a mini Lincoln that I really liked for bodywork. They can be purchased for around $400. They are nice little welders that you can even do some heavy welding with.

Basic Equipment to have:
Hammer and Dolly set (you can purchase from Eastwood or your local paint supply or even Harbour Freight)
MIG welder - what size and voltage is up to you, but most people I know have the 120volt welder (even professional shops)
Cut off wheel
Air saw (if you have air, these are nice to have and come in handy, but not a necessity)
Spot weld cutter or spotweld bits
4 1/2" grinder (HF sell a $20 that lasts a long time)
angle die grinder (many uses, use scotch pads to remove gaskets, light surface rust, use sanding discs to prep area for welding)
Good set of metal drill bits (Dewalt has complete set that Lowes sells for $60)
Good drill (cordless or corded or air, your choice)
Hand shears
Various vise grip pliers (style depends on what you are working on)
Some kind of straight edge, about 12" long (this is helpful in finding high and low spots)
Lots of masking tape and cardboard (cereal box type) for templates
Sharpie, paint pen or soap stone for marking

Optional Equipment:
Oxy/Acet Torch
Metal Brake (for bending metal)
Stud Gun (for pulling dents)
Electric or air metal shears
Air chisel
Flange bender (for making flanges for joining and welding metal)
Hole punch (For spot welding)
Special caulk gun for panel adhesives (and panel adhesives)

There is probably something I missed, but this will help those of you not familiar with metal work to get started.

Bead Roller is really handy for strengthening panels and conturing bends in flat stock as well. Didn't mean to hi-jack but I thought it might be helpful.
Tim:-drink

Lower fender repair
 

This fender isn't from a truck, but should show the process for repairing the rust that plagues all old vehicles.

Someone had spot welded a galvanized patch over the rust hole, which will be the first thing to remove.


http://i5.photobucket.com/albums/y16...Picture127.jpg


http://i5.photobucket.com/albums/y16...Picture128.jpg


The repair piece is started by bending the rear flange, and cutting the relief for the lower bend.


http://i5.photobucket.com/albums/y16...Picture129.jpg


The lower bend is made using a 1/4" radius die in the press brake, but can be done with incremental bends in a regular brake.


http://i5.photobucket.com/albums/y16...Picture138.jpg


http://i5.photobucket.com/albums/y16...Picture131.jpg


Some shrinking and stretching of the rear flange on the Lancasters will start to shape the rear edge.


http://i5.photobucket.com/albums/y16...Picture134.jpg


Followed by some "gentle" bends in the press brake again to match that contour across the piece.


http://i5.photobucket.com/albums/y16...Picture133.jpg


Test fit:


http://i5.photobucket.com/albums/y16...Picture135.jpg


http://i5.photobucket.com/albums/y16...Picture137.jpg


First we'll need to sandblast the inner stiffener to make sure it's solid and epoxy prime all the stuff that will be hidden. Once your paint has cured, then it's time to clamp the lower edge of the patch flush with the bottom, align the sides, and tack weld in place.


http://i5.photobucket.com/albums/y16...2/HPIM6336.jpg


It helps to planish out the weld tacks as you go, to offset the effects of the metal shrinking due to the heat from welding. While many people are of the firm belief that MIG welding is a much harder metal and is difficult to planish, I would suggest metal working the weld one dot at a time, just as we are welding. After planishing the welds, then grind them down to get rid of the bulk and remove any interference in planishing out subsequent weld dots. If you were to wait until the end of the welding process and try to planish out a continuous weld bead, well sure, I guess it would seem harder than the rest of the panel. It's thicker! You'll find it much more manageable to planish out the weld dots as you go.


http://i5.photobucket.com/albums/y16...2/HPIM6337.jpg


With any welding you are doing, check the back side to insure full penetration, or adjust your machine accordingly. If you need to weld it from both sides due to lack of weld penetration, you are increasing the effects of heat to the area, causing more shrinking and panel deformation. Normally I cut my repair panels tight, as you see in the top seam. The side shows a gap, which was due to me cutting too much off the patch as I was fabricating. Normally I would have this as a tight joint as well. You can see that with the gap also comes the increased chance of blowing holes in the metal. I have heard from several "online experts" that you should leave a gap between while welding, some say half the thickness of your welding wire, others use up to 2x that thickness. Anyone who has used the Eastwood type butt weld clamps can attest to the fact that the bigger the gap, the more shrinkage you induce. Ever had the panel lock down on a clamp as you tack on either side of it? In addition to the excessive shrinkage, you now also have increased the likelihood your panel is now moving from the position you clamped it in. These same folks tell me that MIG is a harder material that can not be planished, and yet they want to put more of that material in there by filling a gap. IMHO this theory of filling a gap that has been left open at the joint is due to improper heat settings to obtain full penetration welds, and people have found it easier to just fill in a gap. I think either method will work and provide good results, as long as you are aware up front of the possibility of excessive panel movement and can counter those effects with planishing. In retrospect, in performing the welds on this repair, the weld across the top with the tight joint had little if any panel deformation as compared to the vertical joint with the gap.


http://i5.photobucket.com/albums/y16...2/HPIM6339.jpg


Ground some welds off as I went, gets some of the excess out of the way for planishing the new welds.


http://i5.photobucket.com/albums/y16...2/HPIM6342.jpg


http://i5.photobucket.com/albums/y16...2/HPIM6345.jpg


http://i5.photobucket.com/albums/y16...2/HPIM6346.jpg


The inner fender brace is pulled in snug and plug welded to the lower fender. The rest of the welds are filled in, skipping around as usual to minimize heat buildup, and then ground smooth.


http://i5.photobucket.com/albums/y16...2/HPIM6348.jpg


Welds completed and finished off.


http://i5.photobucket.com/albums/y16...2/HPIM6350.jpg


http://i5.photobucket.com/albums/y16...2/HPIM6352.jpg

I haven't done much body work before, but I am an ironworker. I realize that there are some obvious differences between structural iron and body work, one suggestion that i would through out is that while your tack/ small weld is still hot, hold a hammer/ metal block against the back side and give the tack a few smacks with a hammer. It will take the high point and knock it down and save some work during the grinding/ sanding process. From what I've seen and read, there is a lot of good sound information in this forum.

Thanks for the class on metal work!
 

getting ready to repair a 1970 ford crewcab 4x4 upper corner. borrowing corner from another cab. Parts are getting hard to find for these old trucks. Haven't done this work in a long time but really like these old trucks. gonna modernize this old truck but keep the older look. thanks from wyoming.

MP&C, i have to ask, is that finder from a 55 chevy?

Great write up and info by the way!

Sure is Bill. Thanks, hope the write up will help someone out.

I thought so, my Dad had many a 55-57 cars and early 50's chevy trucks, kinda funny i'm into ford's:-X10

Hey MP&C. that was a great write up and pictures.

From what I have found on the net, planishing involves a hammer and dolly, and tapping or hammering the metal, in this case the weld down and smooth(er). Is this correct? What do you do if you can't get to the back side? I am doing some cab corners and rear fender arches on my '79 and neither place is exactly user friendly to get into.

From your pictures it looks like you did just a spot weld spaced along the seam, then filled in between the welds with more spot welds? I have read weld a little, cool a lot. Is this the method you use?

If you need more practice I have a good place for you do it!!